Programme and Book of Manuscripts

First International Conference for Students and Young Scientists on Materials Processing Science

Tbilisi, 10-13 October 2010

Georgian Ceramic Society Organized on behalf of the European Ceramic Society and JECS TRUST

First International Conference for Students and Young Scientists on Materials Processing Science

Programme and Book of Manuscripts

Tbilisi, 10-13 October 2010

Georgian Technical University TABLE OF CONTENTS

Welcome ...... 4

Schedule at a Glance ...... 5

Opening Ceremony ...... 7

Plenary Speakers ...... 8

Award Lecture ...... 9

Committees ...... 10

International Advisory Committee ...... 10

General Information ...... 13

Participant Scientists and Organizations ...... 15

Symposiums ...... 16

Conference Schedule ...... 17

Contents ...... 20

Manuscripts ...... 22

3 WELCOME

Ladies and gentlemen, dear colleagues,

Georgian Technical University and Ceramists’ Association of Georgia is honored to organize and welcome you to I International Conference for Students and Young Scientists on Materials Processing Science The study and understanding of mechanical, thermal, chemical and functional properties of ceramic materials controlled by their structure and microstructure on atomic level is the main driving force for optimization and development of ceramic technology. The aim of the Conference is to bring together experts, young scientists and production workers from the field of traditional materials, contemporary advanced materials and materials in general, and experimental technology. This is the top ambition of this meeting for scientists in order to convey their experience and achievements in this field. The Conference is divided into three symposia which comprise almost all directions of ceramic materials, such as: nanomaterials and nanotechnologies; experimental high technologies; bioceramics and microbiology; innovations in functional and construction materials and technologies; ceramic and polymer composites; glass, covers and enamel; binding materials and technologies; contemporary problems of studying and expansion of mineral material bases; silicate ceramics and traditional materials; electro-magneto-optical materials and photonics; super conducting ceramics and environment protection; engineering ceramics and environment protection; material science; ceramics in moving bodies and transport. The importance of Conference is broadened as, not only students and doctoral candidates are taking part in it, but also young scientists from the countries of Ceramists International Federation and European Ceramists Association. The young scientists will have the possibility to demonstrate their works and get skills and habits in mastering in this very interesting and sophisticated profession. At the ceremony of opening, besides greeting speeches, you will hear interesting reports. In the work of Conference will participate: Prof. Louis Winnubst - "Ceramic membranes: fabrication, microstructure and transport properties". Prof. Ramaz Katsarava "New Biodegradable Polymers Composed of Naturally Occurring Amino Acids and Materials Based on Them". 114 scientist from seven European countries, 12 scientific-educational institutions are participating in the work of Conference. 37 reports are presented at the Conference. The papers will be published in GECERA journal “Ceramics”. It should be noted that articles in journal “Ceramics” are published in Georgian, English, German and Russian languages. We want to express our special gratitude to European Ceramic Society and JECS TRUST for assistance and support. We wish you pleasant and productive meetings in conference days for your industrious personal, as well as, joint activity enhancement.

Prof. Archil Prangishvili, Prof. Zviad Kovziridze, Rector of Georgian Technical University, President of the Conference, Corresponding member of National Academy Member of the Councils of ICF and ECERS of Sciences of Georgia, President of Engineering Academy of Georgia

4 SCHEDULE AT A GLANCE

Sunday, October 10, 2010

Ragistration 17:00 – 18:30 Best Lecture Award Commission Meeting 18:30 -19:00 Welcome Reception 19:00 –20:30

Monday, October 11, 2010

Speakers Ready Room 09:30 – 18:00 Opening Ceremony 10:00 – 11:00 Symposiums 11:40 – 18:00 Conference Banquet 20:00 – 23:00

Tuesday, October 12, 2010

Speakers Ready Room 09:00 – 18:00 Symposiums 09:00 – 17:00 Excursion 16:30 – 20:00

5 SCHEDULE AT A GLANCE

Wednesday, October 13, 2010

Speakers Ready Room 09:30 – 11:00 Symposiums 10:00 – 11:00 Best Lecture Award Closing Ceremony 12:00

6 OPENING CEREMONY

Monday, October 11, 2010 10:00 Welcome and Introduction Zviad Kovziridze Conference Chairman

Archil Prangishvili Rector of Georgian Technical University.

Plenary speakers 10.30 Louis Winnubst - "Ceramic membranes: fabrication, microstructure and transport properties". University of Twente, Netherlands.

10.45 Ramaz Katsarava - "New biodegradable polymers composed of naturally occurring amino acids and materials based on them". Georgian Technical University, Tbilisi, Georgia.

7 PLENARY SPEAKERS

Dr. Louis Winnubst ([email protected]) Louis Winnubst is a staff member of the Membrane Technology Group of the University of Twente, The Netherlands (http://mtg.tnw.utwente.nl). In 1984 he obtained his doctor’s degree at the same university on the PhD thesis entitled: "Electrical and Interface Properties of Pure and Modified Yttria Stabilized Zirconia". The promotor was Prof. dr. ir. A.J. Burggraaf. At the moment his research activities are in the field of ceramic processing for the development of new inorganic membranes. The objective can be summarized as to achieve technical innovation by understanding the complexity in processing of ceramic materials. He has authored and co- authored more then 120 scientific papers. See further his website: http://mtg.tnw.utwente.nl/people/im/winnubst/ Since 2004 Louis Winnubst is a visiting professor at the School of Chemistry and Materials Science of the University of Science and Technology of China Louis Winnubst (USTC), Hefei (prof. C.S. Chen). He is a member of the Permanent Executive Committee of the European Ceramic Society (www.ecers.org)

Professor Ramaz Katsarava is a full professor and the head of the Center for Medical Polymers and Biomaterials of Technical University of Georgia teaching graduate and post-graduate courses in chemistry, technology and biomedical applications of polymers. At the same time Ramaz Katsarava is Director of the Institute of Medical Polymers & Materials of I.Javakhishvili Tbilisi state University. Ramaz Katsarava is the founder of several new polycondensation methods of polymer synthesis that have been developing since 70-ies of the last century. He and his team pioneered the synthesis of several new families of highly biocompatible and biodegradable non-conventional polymers composed of naturally occurring α -amino acids and other nontoxic building blocks like fatty dicarboxylic acids and diols. These polymers show a widest range of mechanical, physical-chemical and biochemical properties, and have a high potential for practical applications. Some of them are being applied in Ramaz Katsarava industry in the USA, Netherlands and Georgia. Ramaz Katsarava is the World recognized expert in the field of biomedical polymers, a member of several National and International professional organizations. He has more than 270 publications including papers in leading International journal, possesses various Georgian and US patents, 34 grants from National and International Science Foundations. In 2007 Ramaz Katsarava was awarded the World Intellectual Property Organization (WIPO) Gold Medal as an Outstanding Inventor.

8 AWARD LECTURE

Ceramic Membranes: Fabrication, Microstructure and Transport Properties

Louis Winnubst

University of Twente, Netherlands

Research on inorganic membranes at the University of Twente encompasses the fabrication and study of ceramic membranes and their transport properties. This concerns porous membranes with pore sizes down to a few Ångstroms as well as dense, oxygen ion conducting, membranes. Knowledge and control of the microstructure during fabrication is the only way to obtain ceramic materials and devices with special, unique and reproducible properties. It is the aim to develop new, tuneable materials for several technological applications, which requires flexible routes. Some examples will be given in the presentation. Several colloidal techniques and sol-gel methods will be described, resulting in well defined membrane structures, meaning a/o uniform pore sizes. Examples will be given of Hydrothermal stable silica membranes e.g. used for on dewatering of alcohol/water mixtures. These membranes show a good long-term stability under extreme conditions. With regard to dense oxygen conducting membranes several mixed oxygen-ion/electron conducting single phase ceramic oxides with the perovskite structure are investigated. For example the material with composition Ba0.5Sr0.55Co0.8Fe0.2O3-Î´ (BSCF) shows a very good oxygen transport. However these single-phase perovskites are vulnerable to a strong decrease in permeation under CO2-atmosphere. Another disadvantage of perovskite materials is the strong creep beheviour under operating conditions in e.g. membrane reactors. For BSCF a relative high creep rate was found of 1.6% per day at 905°C and a load of 10MPa. Recently studies have started on dual-phase oxygen-selective membranes, consisting of the oxygen-ion conducting stabilized CeO2 and an electron conducting perovskite. Preliminary experiments on a Ce0.8Sm0.2O1.9-La0.8Sr0.2CrO3-Î´ composite membrane show promising oxygen fluxes, while mechanical strength and aging resistance in a CO atmosphere was improved compared to single-phase perovskite membranes. Further information on the Membrane Technology Group of the University of Twente can be found on the following websites http://mtg.tnw.utwente.nl/ http://mtg.tnw.utwente.nl/research/im/

"New Biodegradable Polymers Composed of Naturally Occurring Amino Acids and Materials Based on Them".

Ramaz Katsarava

Center for Medical Polymers and Biomaterials of Georgian Technical University e-mail: [email protected]

The most promising among synthetic biodegradable polymers as materials for various biomedical applications are those entirely composed of naturally occurring and nontoxic (“physiological”) building blocks. α-amino acids are considered as one of the most appropriate naturally occurring candidates for constructing biocompatible macro-chains. Various Amino Acid Based Biodegradable Polymers (AABBPs) - poly(ester amide)s, poly(ester urethane)s, and poly(ester urea)s were originally developed in our labs using new polycondensation methods of polymer synthesis. The polymers obtained are of two types - either regular, containing no lateral functional groups or functional with various active functions like double bonds, carboxylic, hydroxyl, amino and epoxy groups. Both types of AABBPs are promising to be applied as resorbable surgical materials/devices and drug eluting/delivering systems.

9 COMMITTEES INTERNATIONAL ADVISORY COMMITTEE

Conference Chairman Belgium V. Huart, O. van der Biest, F Cambier Zviad Kovziridze Czech Rep. K. Lang, W. Pabst Georgian Ceramists’ Association Denmark K. A. Nielsen 77. Kostava Str. Finland T. Kronberg, T.Mäntylä 0175 Tbilisi, Georgia France A. Leriche, J.F. Baumard, T. Chartier E-mail: [email protected] Georgia Z. Kovziridze Tel. mobile: +00995 99 15 19 57 Germany R. Telle, M Blumenberg Tel: +00995 32 33 53 48

Greece C.Stoumares, V.Dimitropoulos Vice Chairman Hungary J. Szepvolgyi, K. Kovacs Giorgi Donadze Italy P. Zannini, A. Bellosi Georgian Ceramists’ Association Latvia L.Berzina-Cimdina, D.Bajare 77. Kostava Str. Netherlands S. Sinnema, L. Winnubst 0175 Tbilisi, Georgia Norway G.Abrahamsen, S. Pedersen E-mail: [email protected] Poland K. Haberko, Z. Pedzich Tel. mobile: +00995 93 98 66 35 Portugal J. M. Ferreira Tel: +00995 32 33 53 48 Romania M. Preda, A Volceanov

Russia V. Schevchenko, V. Zabrehev Secretary Manana Kekelidze Serbia B. Majevic, S. Boskovic Georgian Ceramists’ Association Slovak Rep. P. Sajgalik, Z. Lences 77. Kostava Str. Slovenia S. Pejavnik, D.Suvorov 0175 Tbilisi, Georgia Spain J. Bakali, C. Baudin E-mail: [email protected] Sweden L. Bergstrom Tel. mobile: +00995 93 36 30 76 Turkey T. Vural, H. Mandal Tel: +00995 32 33 53 48 United Kingdon R. Brook, D. Thompson

10 GECERA Officers

President: Zviad Kovziridze

Vice Presidents: Ramaz Mamaladze, Guram Gaphrindashvili, Archil Sarukhanishvili

Committees:

Zviad Kovziridze, Ramaz Mamaladze, Guram Gaphrindashvili, Archil Sarukhanishvili, Temur Cheishvili, Giorgi Donadze, Manana Kekelidze, Irina Berdzenishvili, Natalia Kiknadze, Amiran Eliozashvili, Zviad Mestvirishvili, Maia Balakhashvili, Nino Darakhvelidze, Nino Zeikidze. Executive Committee:

Conference Chairman: Zviad Kovzirid

Vice-Chairman: Secretary: Giorgi Donadze Manana Kekelidze

Ceramists Association of Georgia was founded in1998. About sixty natural and four juridical persons are united there. In 2004 and 2009 the Association has organized and held two International Conferences where over 300 scientists were present. Since 1999 the Association is regularly publishing referenced journal "Ceramics" where the articles are published in four languages: Georgian, English, German and Rsussian. In October 10-13, 2010, the Ceramists Association of Georgia is holding the 1-St International Conference for Students and Young Scientists on Materials Processing Science on the basis of Georgian Technical University. The conference is held under the protection of ECERS and JECS TRUST.

THE SCIENTIST OF FUTURE NIKOLOZ

12 GENERAL INFORMATION

Organizing Office Georgian Ceramists’ Association Organization Committee works at the address: GTU, 69, Kostava str., building II, ground floor, Direction of the technology of composite materials and articles. 0175 Tbilisi. Tel. mobile: +00995 99 15 19 57 Tel: +00995 32 33 53 48

E-mail: [email protected]

Registration desk Conference registration desk will be located in meeting room on the 3rd floor in administration building. The desk will operate during the following hours: Monday October 11, 2010 9.30 – 18:00 Tuesday October 12, 2010 9.00 – 16:30 Wednesday October 13, 2010 9.00 – 11:00

Identity Badges Badges should be worn during the sessions and social events.

Speakers station The speakers station will be located in meeting room – 3rd floor in administration building. Speakers are kindly requested to hand in all materials of their presentation (USB-kay, CD-ROM ) At least one hour before their scheduled presentation time they will be registered in the meeting room. If a presentation is scheduled early in the morning, speakers are kindly requested to check their presentation at the Speakers Ready Room the day before.

Mobile Phones Mobile phones should be switched off during all sessions.

13 Cloakroom The cloakroom is located on 3rd floor in administration building.

Lunch and Coffee breaks Complimentary tea/coffee and lunch will be served on special areas level 1 in accordance with the time in the programme.

Internet Participants can use the internet on the second floor, Department of International Relations.

Smoking Policy This Conference operates a strict non-smoking policy.

Inside communication Telephone service is in the meeting room.

114 SCIENTISTS FROM SEVEN EUROPEAN COUNTRIES 13 SCIENTIFIC‐EDUCATIONAL INSTITUTIONS ARE PARTICIPATING IN THE WORK OF CONFERENCE

# INSTITUTION 1 Technical University of Clausthal, Clausthal‐Zellerfeld, Germany 2 University of Twente, Netherland 3 Technical University of Braunschwaig, Braunschwaig, Germany 4 “Jožef Stefan” Institute, Jamova 39, 1000 Ljubljana, Slovenia 5 Department of Material Science and Engineering, Anadolu University, Eskisehir, Turkey; Ceramic Research Centre, Eskisehir, Turkey 6 Department of Glass and Ceramics, Institute of Chemical Technology, Prague, Czech Republic 7 Riga Technical University, Riga Biomaterials innovation and development centre, Riga, Latvia 8 Tbilisi State University. Tbilisi, Georgia 9 Andronikashvili Institute of Physics. Tbilisi, Georgia 10 Dvali Institute of Machines Mechanics. Tbilisi, Georgia 11 Caucasian Alexander Tvalchrelidze Institute of Mineral Resources, Tbilisi, Georgia 12 Institute of Hydrometeorology, Department of natural environment pollution monitoring and forecast. Tbilisi, Georgia 13 Georgian Technical University. Tbilisi, Georgia

15 Symposiums

Symposium 1 1. Nanomaterials and nanotechnologies; 2. Experimental high technologies; 3. Bioceramics, microbiology and biomolecular chemistry; 4. Innovations in functional and construction materials and technologies; 5. Contemporary problems of studying and expansion of mineral material bases.

Symposium 2 1. Electro‐magneto‐optical materials and photonics; 2. Engineering ceramics and environmental safety; 3. Materials science; 4. Super conduction ceramics and materials; 5. Materials processing science with lasers as energy sources.

Symposium 3 1. Geopolimers; 2. Glass, covers and enamels; 3. Ceramic and polimer composites; 4. Silicate ceramics and traditional materials; 5. Binding materials and technologies; 6. Ceramics in moving bodies and transport.

16 CONFERENCE SCHEDULE

Tentative Conference Timetable

AM PM EV

Oct.10 Welcome

(Sun) reception Oct.11 Registration, opening Oral presentations Banquet (Mon) ceremony Oct.12 Oral presentations Oral presentations Excursion (Tue) Oct.13 Oral presentations, closing Oral Presentations (Wed) ceremony

Organizers of Symposium October 11: David Jincharadze, Mariam Khomasuridze

Organizers of Symposium October 12: Natalia Kiknadze, Irine Berdzenishvili

Organizers of Symposium October 13: Irine Berdzenishvili, Mariam Khomasuridze

Irine Berdzenishvili David Jincharadze

Mariam Khomasuridze Natalia Kiknadze

17 CONFERENCE SCHEDULE SYMPOSIA WILL BE HELD IN ADMINISTRATION BUILDING OF THE GEORGIAN TECHNICAL UNIVERSITY, III STORY, SMALL CONFERENCE HALL AND MEETING ROOM 11 OCTOBER 2010, MONDAY, MEETING ROOM, III STORY PLENARY SESSION, 10.00 11.00 Coffee break SMALL CONFERENCE HALL SYMPOSIUM I A. Eliozashvili, N. Nizharadze, V. Kinkladze, E. Ukleba, N. Shekriladze, M. Mchedlishvili. Z. Kovziridze. PROCESSING THE TECHNOLOGY OF 11.40 15.40 HIGH REFRACTORY COMPOSITES ON THE DRESSING OF COPPER-GOLD ORE BASIS OF SILICON CARBIDE D. Nozadze, P. Ejibia, R. Khomasuridze. N. Kiknadze, J.G. Hainrich, R. Goerke, GLASS FIBER REINFORCED CONCRETE (GFRC) 12.00 16.00 G.Tabatadze, Z. Kovziridze. NEW COMPOSITE MATERIAL IN CIVIL STRUCTURAL RESEARCH OF AL2O3-TIIC SYS- ENGINEERING TEM NANOCERAMIC COMPOSITE MATERIAL J. Locs, V. Zalite, D. Loca, L. Berzina-Cimdina, D. Vempere. DEVELOPMENT OF POROUS M. Gudiasvili, T. Jishkariani. 12.20 BIOCERAMIC BONE GRAFTS VIA HIGHLY 16.20 ENERGY MANAGEMENT ISSUES VISCOUS MASS FOAMING G. Donadze, G. Mamniashvili, A. Akhalkatsi, V. Totibadze, J. Kakulia, Sh. Malashkhia, D. Daraselia, D. Japharidze, O. Romelashvili, N. Lomidze, L. Kartvelishvili, N. Chubinidze, A. Shengelaia, C. Gavasheli, J.G. Heinrich, T. Guruli. 12.40 Z. Kovziridze 16.40 CONSIDERATION ON THE UTILIZATION OF THE RECEIVING AND STUDY OF HEMATITE CHORDI BARITE-BEARING WASTE NANOPARTICLES FOR HYPERTHERMIA S. Andguladze, V. Gaprindashvili, D. Eristavi, Lunch 13.00 T. Kvinikadze. N. Kobaladze, N. Bibiluri, L. Kristesashvili, 17.00 DETERMINATION OF KEY FACTORS AFFEC- 14.00 N. Chkhubianishvili. TING THE DEGREE OF REDUCTION OF BARITE COLLOIDAL GOLD AND ITS USE IN MEDICINE CONCETRATE OF THE MADNEULI DEPOSIT E. Shapakidze, V. Maisuradze, M. Nadirashvili, N. Gegia, N. Shekriladze, A. Kikabidze, O. Melkadze, S. Kavtaradze, M. Tkemaladze. I. Narozauli, O. Kavtelashvili. 14.20 INVESTIGATION OF THE POSSIBILITY OF BA- 17.20 PEGMATITES OF THE SAZANO DEPOZIT AS RIUM CONTAINING CLINKER PRODUCTION THE SOURCE FOR OBTAINING OF HIGH- USING VOLCANIC ROCKS POTASSIUM FELDSPAR CONCENTRATES Z. Mestvirishvili, J.G. Heinrich, M. Chikovani, А. Аkhalkatsi, T. Gavasheli, Z. Kovziridze. D. Daraselia, D. Japaridze, А. Shengelaia, 14.40 IMPROVEMENT OF BORON CARBIDE MECHA- G. Маmniashvili, T. Gеgechkori, М. Оkrosashvili, NICAL PROPERTIES IN B-C-TI SYSTEM 17.40 E. Kutelia, А. Peikrishvili. MAGNETOMETRY AND NMR STUDY OF NA- 15.00 Coffee break NOSIZED COBALT POWDERS SYNTHESIZED WITH ELECTRON-BEAM TECHNOLOGY 12 OCTOBER 2010, THUESDAY, MEETING ROOM, III STORY

SYMPOSIUM II M. Tabatadze, N. Buachidze, L. Intskirveli, D. Macharadze, D. Nozadze, M. Okrosashvili, R. Kediashvili, G. Kuchava, N. Beglarishvili. T. Namicheishvili, Ya. Tavartkiladze, S. Bohm. 09.00 ECOLOGICAL MONITORING OF THE RIVER 10.00 COMBINED METHOD OF ELECTRIC CONTACT LIAKHVI AND EVALUATION OF THE HEATING AND DIFFUSION CONNECTION OF CURRENT SITUATION STEEL-ALUMINUM A. Berechikidze, M. Gogadze, M. Kurdghelia, 10.20 Coffee breack L. Kotiashvili. M. Gugeshidze. 09.20 FATIGUE STRENGTH OF STEEL SAMPLES PRINCIPLES OF IN-LINE EVALUATION OF BEFORE AND AFTER THEIR RECOVERY WITH 11.00 SOLID WASTES IN GEORGIA ON EXAMPLE OF ELECTRIC CONTACT WELDING-ON OF A TAPE THE RUSTAVI METALLURGICAL WORKS A. Sulamanidze, A. Neverov, A. Metreveli. Sh. Nemsadze, M. Giuashvili. 09.40 PROBLEMS AND PERSPECTIVES 11.20 ON DIAGNOSTICS OF PIEZOCERAMIC MEA- CONNECTION MATERIALS SURING TRANSDUCER

SYMPOSIUM III D. Loca, J. Locs, K. Salma, L. Berzina-Cimdina. M. Tsintsadze, Kh. Tsikarishvili, R. Chagunava. BIODEGRADABLE POLYMER COATINGS ON SIMPLIFIED METHOD OF OLD KVEVRI (WINE 11.40 CALCIUM PHOSPHATE POROUS BONE 14.20 VESSEL) DIGGING OUT FROM THE GROUND SCAFFOLDS FOR DRUG DELIVERY N. Inanashvili. G. Basilaia, J. Aneli, L. Nadareishvili. CHARACTERISTICS OF LITHOLOGIC- 14.40 GRADIENTLY ANISOTROPIC CONDUCTING PETROGRAPHIC-MINERALOGICAL POLYMER COMPOSITES 12.00 COMPOSITION OF ARCHAELOGICAL CERAMIC WARE REVEALED ON THE 15.00 Coffee break TERRITORY OF GEORGIA N. Kamushadze, L. Gabunia, E. Shapakidze, U. Došler, M.M. Kržmanc, D. Suvorov. I. Gejadze, R. Kvatashidze, M. Khutsianidze. 12.20 NUCLEATION AND CRYSTALLIZATION OF 15.40 STUDY OF ACID MAGMATIC ROCKS OF THE MGO-B2O3-SIO2 GLASS SOUTH-EAST GEORGIA FOR THE PURPUZE OF USE IN GLASS AND CERAMICS PRODUCTION J. Hostaša, W. Pabst. N. Zeikidze, I. Berdzenishvili. ANALYTICAL AND NUMERICAL CALCULATI- INVESTIGATION AND DEVELOPMENT OF ONE- 12.40 ONS OF THE THERMAL CONDUCTIVITY OF 16.00 COAT GLASS ENAMELS WITH BEST AL2O3-ZRO2 COMPOSITE CERAMICS ADHERENCE PROPERTIES 13.00 Lunch M. Shavlakadze, T. Cheishvili. Ö. Cengiz, A. Kara. SYNTHESIS OF SPECIAL MATERIALS ON THE 16.20 EFFECT OF PYROPHILLITE ON FIRING BEHA- 14.00 BASIS OF MANGANESE BEARING RAW MA- VIOUR OF MONOPOROSA WALL TILE BODIES TERIAL AND INVESTIGATION OF SOME THEIR PROPERTIES

13 OCTOBER 2010, WEDNESDAY, MEETING ROOM, III STORY

SYMPOSIUM III D. Jincharadze, N. Bokuchava. DEVELOPMENT OF COSMETIC COMPOSITIONS 9.40 CONTAINING KAOLINE, BENTONITE AND L. Gventsadze. PELOID DEVELOPMENT OF HIGH-TEMPERATURE M.Balakhashvili, N. Nizharadze, D. Gventsadze, 10.40 ECOLOGICALLY CLEAN FRICTION M. Mshvildadze, Z. Kovziridze. MATERIALS OF NEW GENERATION AND 10.00 STUDY OF DOLOMITE FROM THE SKURI STUDY OF THEIR WEAR PROPERTIES DEPOSIT FOR RECEIVING HIGH REFRAC- TORY COMPOSITE М. Chikovani, А. Akhalkatsi, T. Gavasheli, G. S. Sanadze, G. Gaprindashvili. Mamniashvili, Т. Gegechkori, D. Gventsadze. 11.00 PECULIARITIES OF SYNTHESIS OF SELENIUM- INDUCTIVE EXCITATION OF MAGNETOELEC- CADMIUM RED ENAMELS 10.20 TRIC RESPONSES IN LAYERED MAGNETO ELECTRIC COMPOSITE MATERIALS USING 11.20 Coffee break MAGNETIC VIDEO-PULSE EXCITATION

BEST LECTURE AWARD 12.00 CLOSING CEREMONY

19 CONTENTS

E. Ukleba, N. Shekriladze, M. Mchedlishvili. PROCESSING OF THE TECHNOLOGY OF DRESSING OF COPPER-GOLD ORE ...... 22 D. Nozadze, P. Ejibia, R. Khomasuridze. GLASS FIBER REINFORCED CONCRETE (GFRC) NEW COMPOSITE MATERIAL IN CIVIL ENGINEERING ...... 27 D. Loca, J. Locs, K. Salma, L. Berzina-Cimdina, V. Zalite, D. Vempere. DEVELOPMENT OF POROUS CALCIUM PHOSPHATE BONE SCAFFOLDS FOR DRUG DELIVERY ...... 33 G. Donadze, G. Mamniashvili, A. Akhalkatsi, D. Daraselia, D. Japharidze, O. Romelashvili, A. Shengelaia, C. Gavasheli, J.G. Heinrich, Z. Kovziridze. THE RECEIVING AND STUDY OF HEMATITE NANOPARTICLES FOR HYPERTHERMIA ...... 37 N. Kobaladze, N. Bibiluri, L. Kristesashvili, N. Chkhubianishvili. COLLOIDAL GOLD AND ITS USE IN MEDICINE ...... 46 E. Shapakidze, V. Maisuradze, M. Nadirashvili, O. Melkadze, S. Kavtaradze, M. Tkemaladze. INVESTIGATION OF THE POSSIBILITY OF BARIUM CONTAINING CLINKER PRODUCTION USING VOLCANIC ROCKS ...... 49 Z. Mestvirishvili, J.G. Heinrich, Z. Kovziridze. IMPROVEMENT OF BORON CARBIDE MECHANICAL PROPERTIES IN B-C-TI SYSTEM ...... 55 A. Eliozashvili, N. Nizharadze, V. Kinkladze, Z. Kovziridze. HIGH REFRACTORY COMPOSITES ON THE BASIS OF SILICON CARBIDE ...... 60

N. Kiknadze, J.G. Hainrich, R. Goerke, G.Tabatadze, Z. Kovziridze. STRUCTURAL RESEARCH OF AL2O3-TiC SYSTEM NANOCERAMIC COMPOSITE MATERIAL ...... 66 M. Gudiasvili, T. Jishkariani. ENERGY MANAGEMENT ISSUES ...... 72 V. Totibadze, J. Kakulia, Sh. Malashkhia, N. Lomidze, L. Kartvelishvili, N. Chubinidze, T. Guruli. CONSIDERATION ON THE UTILIZATION OF CHORDI BARITE-BEARING WASTE ...... 76 S. Andguladze, V. Gaprindashvili, D. Eristavi, T. Kvinikadze. DETERMINATION OF KEY FACTORS AFFECTING THE DEGREE OF REDUCTION OF BARITE CONCETRATE OF THE MADNEULI DEPOSIT ...... 80 N. Gegia, N. Shekriladze, A. Kikabidze, I. Narozauli, O. Kavtelashvili. PEGMATITES OF THE SAZANO DEPOZIT AS THE SOURCE FOR OBTAINING OF HIGH-POTASSIUM FELDSPAR CONCENTRATES ...... 83 M. Chikovani, А. Аkhalkatsi, T. Gavasheli, D. Daraselia, D. Japaridze, А. Shengelaia, G. Маmniashvili, T. Gеgechkori, М. Оkrosashvili, E. Kutelia, А. Peikrishvili. MAGNETOMETRY AND NMR STUDY OF NANOSIZED COBALT POWDERS SYNTHESIZED WITH ELECTRON-BEAM TECHNOLOGY ...... 88

M. Tabatadze, N. Buachidze, L. Intskirveli, R. Kediashvili, G. Kuchava, N. Beglarishvili. ECOLOGICAL MONITORING OF THE RIVER LIAKHVI AND EVALUATION OF THE CURRENT SITUATION ...... 95 A. Berechikidze, M. Gogadze, M. Kurdghelia, L. Kotiashvili. FATIGUE STRENGTH OF STEEL SAMPLES BEFORE AND AFTER THEIR RECOVERY WITH ELECTRIC CONTACT WELDING‐ON OF A ...... 100

20 A. Sulamanidze, A. Neverov, A. Metreveli. PROBLEMS AND PERSPECTIVES CONNECTION MATERIALS ...... 104 D. Macharadze, D. Nozadze, M. Okrosashvili, T. Namicheishvili, Ya. Tavartkiladze, S. Bohm. COMBINED METHOD OF ELECTRIC CONTACT HEATING AND DIFFUSION CONNECTION OF STEEL-ALUMINUM ...... 108 M. Gugeshidze. PRINCIPLES OF IN-LINE EVALUATION OF SOLID WASTES IN GEORGIA ON EXAMPLE OF THE RUSTAVI METALLURGICAL WORKS ...... 114 Sh. Nemsadze, M. Giuashvili. ON DIAGNOSTICS OF PIEZOCERAMIC MEASURING TRANSDUCER ...... 119

N. Inanashvili. CHARACTERISTICS OF LITHOLOGIC-PETROGRAPHIC-MINERALOGICAL COMPOSITION OF ARCHAELOGICAL CERAMIC WARE REVEALED ON THE TERRITORY OF GEORGIA ...... 121 U. Došler, M.M. Kržmanc, D. Suvorov. NUCLEATION AND CRYSTALLIZATION OF MGO-B2O3-SIO2 GLASS ...... 126 J. Hostaša, W. Pabst. ANALYTICAL AND NUMERICAL CALCULATIONS OF THE THERMAL CONDUCTIVITY

OF AL2O3-ZRO2 COMPOSITE CERAMICS ...... 131 M. Shavlakadze, T. Cheishvili. SYNTHESIS OF SPECIAL MATERIALS ON THE BASIS OF MANGANESE BEARING RAW MATERIAL AND INVESTIGATION OF SOME THEIR PROPERTIES ...... 138 M. Tsintsadze, Kh. Tsikarishvili, R. Chagunava. SIMPLIFIED METHOD OF OLD KVEVRI (WINE VESSEL) DIGGING OUT FROM THE GROUND ...... 142 G. Basilaia, J. Aneli, L. Nadareishvili. GRADIENTLY ANISOTROPIC CONDUCTING POLYMER COMPOSITES ...... 145 N. Kamushadze, L. Gabunia, E. Shapakidze, I. Gejadze, R. Kvatashidze, M. Khutsianidze. STUDY OF ACID MAGMATIC ROCKS OF THE SOUTH-EAST GEORGIA FOR THE PURPUSE OF USE IN GLASS AND CERAMICS PRODUCTION ...... 148 N. Zeikidze, I. Berdzenishvili. INVESTIGATION AND DEVELOPMENT OF ONE-COAT GLASS ENAMELS WITH BEST ADHERENCE PROPERTIES ...... 151 Ö. Cengiz, A. Kara. EFFECT OF PYROPHILLITE ON FIRING BEHAVIOUR OF MONOPOROSA WALL TILE BODIES ...... 155 D. Jincharadze, N. Bokuchava. DEVELOPMENT OF COSMETIC COMPOSITIONS CONTAINING KAOLINE, BENTONITE AND PELOID ...... 156 M. Balakhashvili, N. Nizharadze, D. Gventsadze, M. Mshvildadze, Z. Kovziridze. STUDY OF DOLOMITE FROM THE SKURI DEPOSIT FOR RECEIVING HIGH REFRACTORY COMPOSITE ...... 162 М. Chikovani, А. Akhalkatsi, T. Gavasheli, G. Mamniashvili, Т. Gegechkori, D. Gventsadze. INDUCTIVE EXCITATION OF MAGNETOELECTRIC RESPONSES IN LAYERED MAGNETO ELECTRIC COMPOSITE MATERIALS USING MAGNETIC VIDEO-PULSE EXCITATION ...... 169 L. Gventsadze. DEVELOPMENT OF HIGH-TEMPERATURE ECOLOGICALLY CLEAN FRICTION MATERIALS OF NEW GENERATION AND STUDY OF THEIR WEAR PROPERTIES ...... 173 S. Sanadze, G. Gaprindashvili. PECULIARITIES OF SYNTHESIS OF SELENIUM-CADMIUM RED ENAMELS ...... 178

MANUSCRIPTS

UDC 662.772÷662.765.061.24 PROCESSING OF THE TECHNOLOGY OF DRESSING OF COPPER‐GOLD ORE E. Ukleba*, N. Shekriladze*, N.Gegia*, M. Mchedlishvili** *LEPL Caucasian Alexander Tvalchrelidze Institute of Mineral Resources, 85, Paliashvili str. Tbilisi 1079, Georgia; **Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava str. Tbilisi, 0175, Georgia.

E‐mail: [email protected] are various: the underground, i.e. local leaching, dense Resume: The results of the technology of dressing of and vat leaching. Chemical mechanisms of all these copper‐gold ore are presented. As a result of researches it processes, of copper ores leaching, are identical. is stated that only 24% of copper (floats only the malachite) Latest achievements in the technology of extraction ‐ has flotation ability and copper which is connected with sili‐ electrolysis and the low capital and operational expendi‐ cate phase remains in the tail. Therefore, it is not appropri‐ tures make the methods of leaching gradually taking a ate to use flotation method for dressing of this ore. In large leading place in copper manufacture. quantities the ore contains copper minerals (98‐99%), The purpose of the presented work was the investiga‐ which are well dissolved in sulfuric acid. Therefore, for ore tion of the technology of the primary processing of oxidized processing the method of hydrometallurgy was selected, in copper‐gold ores using the method of chemical dressing. this case sulfuric acid was applied as a solvent. 2. THE BODY OF THE ARTICLE For studying the technological properties of ore the Key words: copper; gold; ore; flotation; sulfuric ac‐ test was carried out on the solubility in sulfuric acid. id; leaching. Only 53% of copper has passed from ore to the solu‐ tion of sodium cyanide. This indicates that insoluble 1. INTRODUCTION copper is connected with aluminosilicate and silicate Depending on the content of the oxidized minerals and phase. The minerals of such types float with difficulty or forms of sulfides, copper ores are divided into the oxida‐ not at all, that is why extraction of copper is 3‐4% lower tion, the mixed and the primary chalcopyrite‐bornite. De‐ than extraction into cyanic drawing. pending on the type of ore the methods of processing can The ability of natural flotation of ore has been studied be flotation, hydrometallurgy or their combination. in order to state fitness of flotation method for its enrich‐ To the present days flotation remains the dominant ment. The results of the experiment are presented in Ta‐ method of dressing of copper ores and is irreplaceable ble 1. for processing of complex sulfide ores. For oxidized and Only 24% of copper has the ability of natural flotation mixed ores, the hydrometallurgical, i.e. chemical method (Table 1). Visually only malachite floats and copper con‐ of dressing or its combination with flotation is success‐ nected with silicate phase remains in tails, from where fully used. Technical ways which solve these processes

76% are extracted. Copper contents in tails is 0,5%, while for ore processing the method of hydrometallurgy was initial ore contains 0,6‐0,62%. selected, in this case sulfuric acid is applied as a solvent. In the concentrates 37% of gold is extracted, while The experiments were carried out on the samples of 63% remains in tails. Therefore, the natural flotation of 1 kg mass in open and closed mixers. copper‐gold ores is low and ore dressing by this method The factors acting on the process of copper dissolu‐ is not advisable. tion: expenditure and concentration of solvent, time of Ore contains copper minerals in large quantities (98‐ leaching, coarseness of material, s : l relationship, tem‐ 99%) which are dissolved well in sulfuric acid. Therefore, perature were studied.

Table 1 The experimental results of natural flotation of ore

Yield, Content of the components Extraction of the components, % Product designation % Cu, % Au, g/t Cu Au I fraction 2.0 2.2 18.5 6.9 25.8 II fraction 1.9 2.4 5.4 7.3 7.2 III fraction 1.3 3.8 2.8 7.4 2.4 IV fraction 0.8 2.0 3.2 2.6 1.9 I‐II fractions 5.8 0.5 9.0 24.2 37.3 Tails 94.2 0.5 0.9 75.8 62.7 On the balance 100.0 0.62 1.4 100.0 100.0 According to the 0.6 1.2 chemical analysis

Concentration and expenditure of sulfuric acid de‐ extraction of copper from ore must be taken as 10%. pends on mineral composition of ore. For example, ma‐ During one hour more than 80% of copper is lixiviated, lachite, azurite, bornite and atacamite are readily so‐ the concentration of solution is 2.5 g/l of copper. In the luble. Copper connected with silicates, phosphates, etc. process of circulation of this solution the concentration lixiviate slowly and incompletely. of the dissolved copper increases and this, in its part, The dependence of sulfuric acid concentrations on simplifies the extraction – electrolysis or extraction‐ copper extractions in the solution is given in Fig. 1. Op‐ electrolysis ‐ of copper from the solution. timum concentration of sulfuric acid for the maximum

he extraction of he extraction copper, % 74

72 0246810121416 the concentrations of sulfuric acid, %

Fig. 1. The dependence of copper extraction in the solution on sulfuric acid concentrations

92 90 88 (2) (3) 86 84 the extraction of cooper, % the extraction 82 (1) 80 78 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 the period of the leaching, hr

Fig. 2. The dependence of copper extraction on the period of leaching: 1) Sulfuric acid concentrations – 5% (50g/l), 2) Sulfuric acid concentrations – 10% (100g/l), 3) Sulfuric acid concentrations– 150% (150g/l)

100

85 (2)

the extraction of copper, % the extraction (1) 75

70 0123456

the concentrations of sulfuric acid , %

Fig. 3. The dependence of different coarseness ore lixiviation on solvent concentrations: 1) Material coarseness ‐3 + 0 mm, 2) Material coarseness ‐1 + 0 mm

99 98.5 98 97.5 97 96.5

the extraction of copper, % the extraction 96 95.5 95 02468101214 the concentrations of sulfuric acid , %

Fig. 4. Relation of copper extraction and sulfuric acid concentrations

The duration of lixiviation process depends on the This indicates that at usual temperature the same variety of copper minerals and concentrations of acid. value can be achieved after increasing the time of The higher the concentration of acid, the sooner it is leaching. spent. In this case not only copper, but also the minerals Furthermore, the results of experiments conducted of other elements are dissolved, all this increases the ex‐ in the open and closed mixers were compared. In open penditure of acid. mixer 83.3% of copper has passed to solution of 5% sul‐ Proceeding from the above mentioned, for the estab‐ furic acid, during one hour, on 28‐300C temperature, lishment of time of leaching the experiments with use of while in closed mixer, in the same conditions, only ‐ 80%. 5, 10 and 15% (i.e., 50 g/l, 100 g/l and 150 g/l) sulfuric The same occurs with high concentration solutions. For acid were carried out. The results are given in Fig. 2. example, the solution of 10% sulfuric acid, for one hour, As it is seen from Fig. 2, the speed of leaching with in open mixer dissolves 85%, and in the closed ‐ 83% use of 10% and 15% solvent are close and during 4 hours copper. 90 % of copper passes from ore into solution. As to the action of coarseness on the process of 3. CONCLUSION leaching, because of limited choice of samples, the expe‐ Thus, as the results have proved, the primary riments were carried out on ‐3 + 0 mm and ‐1 + 0 mm processing of copper-gold ores using hydrometallurgical dimension of material. The reaction rate and the quality method allows to extract more than 90% copper from of copper extraction is almost 10% more in the case of copper-gold ores. coarseness of ‐1 + 0 mm than of coarseness of ‐3 + 0 mm (Fig.3). References Temperature is an important parameter for the 1. S. I. Mitrofanov. Combined methods of processing the oxidized and mixed copper ores. Publishing house process of leaching (Fig.4.). If we compare the experi‐ “NEDRA”, Moscow, 1970. mental results carried out, using 10% of sulfuric acid and 2. S.I. Polkin, E.B.Adams. Enrichment of colored and 0 3 hour leaching, on different temperatures (25‐28 C and rare metal ores. Publishing house "NEDRA", Moscow, 0 35‐38 C), we will see that copper extraction into solution 1975. exceeds 98%, which actually equals even theoretical re‐ 3. S.I.Polkin, E.B.Adams. Enrichment of nonferrous met‐ sults, i.e., results obtained by chemical‐phase analysis. al ores. Publishing house "NEDRA", Moscow, 1983.

uak 662.772÷662.765.061.24 spilenZ-oqros madnis gamdidrebis teqnologiis damuSaveba e. ukleba*, n. SeyrilaZe*, n. gegia*, m. mWedliSvili** *ssip al. TvalWreliZis mineraluri nedleulis instituti, Tbilisi, 0179, faliaSvilis 85, saqarTvelo; **saqarTvelos teqnikuri universiteti, qimiuri da biologiuri teqnologiebis departamenti, Tbilisi, 0175, kostavas 69, saqarTvelo.

reziume: warmodgenilia spilenZ-oqros madnis gamdidrebis teqnologiis kvlevis Sede- gebi. dadasturebulia, rom flotaciis bunebrivi unari spilenZis mxolod 24% aqvs. flo- tirebs mxolod malaqiti, xolo silikatur fazasTan dakavSirebuli spilenZi kudSi rCe- ba. amotom flotaciiT maTi gamdidreba mizanSewonili ar aris. gogirdmJavaSi xsnadi spilenZis mineralebis Semcveloba madanSi maRalia _ 98-99%, amitom SerCeulia misi gada- muSavebis hidrometalurgiuli meTodi, gamxsnelad gogirdmJavas gamoyenebiT.

sakvanZo sityvebi: madani; spilenZi; oqro; gogirdmJava; gamotutva.

UDC 691 GLASS FIBER REINFORCED CONCRETE (GFRC), NEW COMPOSITE MATERIAL IN CIVIL ENGINEERING D. Nozadze, P. Ejibia, R. Khomasuridze Department of Metallurgy and Materials Science. Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia E‐mail: [email protected] The most common form of glass fibers, E‐glass, is Resume: Glass fiber reinforced concrete (GFRC) is used as a reinforcing material in resin composites re‐ essentially Portland cement‐based composite with short ferred to as FRP. However, when E‐glass fibers are ex‐ glass fibers that are normally randomly distributed posed to Portland cement based mixtures, such as mor‐ throughout the material. The resulting composite offers tars, or regular concrete, the alkaline nature of the ce‐ a unique balance of properties such as strength, tough‐ mentitious mixtures rapidly deteriorates the glass fiber. ness, dimensional stability, environmental durability, Because of this, alkali resistant AR glass fibers were de‐ moisture resistance, freeze resistance, fire resistance, veloped by intrinsically modifying chemical composition aesthetics and ease of handling and installation. of glass fibers such that they are inherently more chemi‐ The paper explains the fundamental principles of cally resistant to the alkaline nature of cementitious ma‐ GFRC and gives examples of some of their uses on Geor‐ trix. gian market. These applications range from high quality architectural wall panels and decorative elements to low 2. THE BODY OF THE ARTICLE cost manhole covers. New developments and techniques In order to make glass fibers resistant to the lime will also be touched upon. generated during the setting of Portland cement, zirco‐ nium is added to glass mixture composition prior to Key words: AR glass fibers; AR meshes; AR mats; melting and fiberising the raw materials. The added zir‐ engineering properties; manufacturing methods; wall conium becomes part of glass fiber molecular structure panels; durability, decorative elements; fiber concrete; on the manufacturing process i.e. it is not just a protec‐ fiber reinforcement. tive coating. The minimum zirconium content in the composition for good durability is about 16% by weight.

1. INTRODUCTION The glass fibers with zirconium modification are usually Fiber reinforced composite materials consist of high referred to as alkali‐resistant glass fibers, or AR glass fi‐ strength fiber embedded in matrix. In this form, both fi‐ bers. AR glass fibers are chemically stable resisting both ber and matrix retain their physical and chemical identi‐ alkali and acid conditions. Chemical composition of AR ties, yet they produce a combination of properties that glass fibers is shown in Table 1 and physical and mechan‐ cannot be achieved with either components acting ical properties are given in Table 2. alone. In general fibers are principal load‐carrying mem‐ AR‐glass fibers for use in concrete are available in bers, while the surrounding matrix keeps them in desired these basic forms – discrete chopped strand [CS], conti‐ locations and orientation, acting as a load transfer me‐ nuous roving, mesh and mat. dium between them, and protects them from environ‐ 1 AR‐glass fiber discrete chopped strands – are used mental damage. In fact, the fibers provide reinforcement primarily in premix glass fiber reinforced concrete (high for the matrix and other useful functions in fiber‐ dose rate) and in crack control of concrete (low dose reinforced composite materials. rate). Typically, AR‐glass CS are available in two types, Cement based materials have inherent defects such integral and water dispersible. Glass fiber CS are made as flaws in the matrix, due to shrinkage and debonding up of bundles of individual filaments with the diameter at interfaces. Glass fibers in this brittle cementitious of 12‐20 microns. materials help to enhance the composite toughness 2 Integral chopped strands – are designed to stay as and tensile strength by synergistically interacting with bundles of filaments through mixing and placing, with as the micro cracks that develop when composite is little breakdown of the bundle as possible.The number loaded. The glass fibers restrain crack opening and of filaments per bundle is usually referred as strand crack growth by effectively bridging across the micro geometry. The diameter of the individual filaments, the cracks.

number of filaments that are bundled together, and the Table 2 integrity of the bundle are the key factors that deter‐ Physical and mechanical properties of mine performance characteristics of the strand. The typ‐ AR‐glass fibers, percent by weight (PCI MNL‐128‐01) ical length of discrete AR‐glass fiber strands used in thin‐ reinforced products ranges between 6 to 40 mm. The Property Value strand geometry, strand length, and glass fiber content, Specific gravity 2.70-2.74 all contribute to the processing characteristics of the Tensile strength, MPa 1700 composite and its final properties. Modulus of elasticity, GPa 72 3. Water dispersible chopped strands – are designed to disperse quickly into individual strands on contact Strain at break, % 2.0 with water or an aqueous cementitious mixture. These fibers are used in composites where a fine dispersion of individual mono‐filaments is desired rather than intact fiber bundles. In particular, water dispersible AR‐glass is commonly used to reduce cracking in concrete, mor‐ tars and stucco application and in manufacturing process that involve cementitious slurries with initial high water content such as modified Hatschek process or for calcium and sodium silicate applications fre‐ quently using fiber‐press processes. Typical length of Fig.1a water dispersible AR‐glass fiber strands used in thin‐ reinforced cement product ranges from 6 to 25 mm. 4. Continuous AR‐glass fibers – are available in the (Fig.1a) form of roving (Fig 1b).

Table 1 Chemical composition of AR‐glass fibers, percent by weight (PCI MNL‐128‐01)

Component Percentage (%) 61.0-62.0 SiO 2

Na2 O 14.8-15.0 CaO - Fig. 1b MgO - A roving is an assemblage of several continuous AR‐ K O 0.0-0.2 2 glass fiber mono‐filaments. The manner in which the

Al 2 O3 0.0-0.8 mono‐filaments are assembled varies and differentiates one roving type from another. Fundamentally, the con‐ Fe O - 2 3 struction of an AR‐glass fiber roving is as follows: z Several continuous alkali‐resistant glass fiber B2O 3 - mono‐filaments are gathered together to form a ZrO2 16.7-20.0 continuous strand. The typical diameter of the individual alkali‐resistant glass fiber mono‐filaments ranges from TiO 2 0.0-0.1 10 to 20 microns. Typically, the number of mono‐ Li 2O 0.0-1.0 filaments that are gathered together to form a continuous strand ranges from 50 to 400.

z Several continuous strands as explained above with chopped fibers in a mix. This method requires less are assembled together to form a continuous roving. expertise than the hand spray‐up method and results in Typically, the number of continuous strands that are higher strengths than with vibration casting. Cost of assembled to form a continuous roving ranges from 20 GFRC as a material, however, is much more expensive to 100. than conventional concrete on weight‐for‐weight basis. 5. Glass fiber meshes and mats – are woven or dip‐ But since the cross sections can be so much thinner, the ped, non‐woven products form assembled glass fiber cost is overcome in most decorative elements. With rovings or strands whilst mats are chopped fibers GFRC, concrete can be cast in thinner sections and is bonded together with polymeric coating. Traditionally therefore 75% lighter than similar pieces cast with tradi‐ they were woven products of heavily coated E‐glass fiber tional concrete. yarn used mainly in the production of cement boards. The mechanical properties of GFRC composites de‐ As an alternative, an alkali‐resistant (AR) glass fiber mesh pend upon fiber content, water/cement ratio, density, has recently been used in a new system for seismic im‐ sand content, fiber orientation, fiber length and admix‐ provement of masonry walls. ture content. Typical properties for traditional premix sprayed GFRC containing 5% by weight of glass fibers are show in Table 3 (PCI MNL‐128‐01). As the Table shows, GFRC composites have significant load and strain capaci‐ ty. Whilst some of these properties reduce a little with time for standard GFRC their real time performance is well documented and all accepted design procedures al‐ low for establishing design values. PCI Publication MNL‐ 128‐01, “Recommendations for Glass Fiber Reinforced Concrete Panels” details the most widely accepted de‐ sign procedure in the industry.

Table 3

Fig. 1c Typical range of premix sprayed GFRC properties (PCI MNL‐128‐01) AR GFRC is well known for its high mechanical prop‐ Value after erties, compared to plain concrete or even steel rein‐ Property forced concrete, but additional reinforcement of con‐ 28 days crete with AR‐glass fiber mesh allows us to increase not Dry density, t/cu.m. 1.8-2.0 only the tensile and impact strengths, but also drastically Compressive strength MPa 40-60 improve materials bending properties. Flexural strength: MPa Traditional spray‐up GFRC is a low water‐cement ra‐ Yield (FY) 58-80 tio mix. Sand and cement are typically used at a ratio of Ultimate strength (FU) 10-14 about 1 to 1, the fibers are added to the mix at about 2% Modulus of elasticity GPa 7-20 to 3% for premixed GFRC or 4% to 6% by weight for spray‐up mixes. We also use admixtures of silica fume Direct tension: MPa Yield (TY) and high range water reducer superplasticizer to this 4-6 Ultimate tension (TU) mix. This reduces the permeability of concrete, making it 4-7 Strain to failure % 0.1-2 more water resistant and also reduces the alkalinity of concrete, which means it doesn't affect the glass – both Shear :MPa of these factors mean increased concrete durability. In-plane 4-7 The traditional, and perhaps still the best, way to −6 Coef. Of thermal expansion /C 10-20 x 10 manufacture precast GFRC elements is by hand spraying 0 the GFRC into a mold. This is how most precast GFRC Thermal conductivity W/ m C 0.5-1.0 architectural cladding panels are made and also most ornamental precast GFRC. We sprayed premixed GFRC,

Most of the other methods to improve durability of ices and column covers. Fig. 2 shows a photograph of the GFRC rely on either the use of pozzolanic admixtures shopping center Karvasla in Tbilisi in which 2600 square such as metakaolin or fly ash [1,2] or use of special ce‐ meters of building exterior was clad with GFRC architec‐ ments such as, calcium sulphoaluminate cements that do tural facade panels. The panel size varied but the aver‐ not produce calcium hydroxide as a hydration product. age was approx. 1,0 m x 2,0 m. The panel skin consisted GFRC in Georgia is used as: of 12.5 mm thick GFRC. The intricate architectural details GFRC architectural facade panels – can be manufac‐ on these panels were created by forming the panels over tured as window units, spandrels, soft‐fit and fascia pa‐ rubber liner molds (Fig. 2). nels, mansard roof elements, as well as, mullions, com‐

Fig. 2

GFRC decorative elements – are capable of closely deteriorated original carvings. GFRC architectural ele‐ imitating natural materials, which tend to be expensive ments are relatively light in weight and require low and in short supply. Thin complex shapes with excellent maintenance. These attributes make GFRC architectural surface finish and surface details can be easily formed elements a sensible choice for both new and refurbished using AR‐glass fiber reinforced cementitious materials. buildings. Figure 3a and 3b show some applications. Molds to form these shapes are frequently taken from

Fig.3a Fig.3b

Manhole and drainage channel covers – for drainage and transporting liquids represent another application for GFRC. Fig. 4a and Fig.4b show a rain‐water drainage channel covers and manhole covers. These products are designed for optimum flow capacity and are available for different EN 124 loads. Further, these products are lightweight, low cost and easy to install.

Fig. 4b

3. CONCLUSION GFRC (glass fiber reinforced concrete) can be used as wall panels, window surrounds, spandrels, column cov‐ ers, soft‐fits, brackets, quoins, railings, pilasters, copings, domes, manhole and drainage channel covers. The basic flexibility of use makes this an ideal use for many landscaping jobs. Uses in landscape as well as hard‐ scrape include site furnishings, planters, bollards, urns, tables, fountains, marine structures, pools, rock founda‐ tions, besides, GFRC can be used in historical restora‐ tions and renovations, for the replication of building or‐ naments, carved stone and even wood.

References 1. S. Marikunte, C. Aldea, S.D. Shah. Durability of glass fiber reinforced cement composites, Journal of Ame‐ rican Ceramic Society 80, 1997, p.2326‐2332. Fig. 4a 2. P. Soukatchoff, P. Ridd. High durability GRC using a

modified cementitious matrix. International Congress

of GRCA, Maastricht 89, 1991.

uak 691 minaboWkoTi daarmaturebuli betoni – axali kompoziciuri masala samoqalaqo mSeneblobaSi d. nozaZe, p. ejibia, r. xomasuriZe saqarTvelos teqnikuri universiteti, metalurgiisa da masalaTmcodneobis departamenti, Tbilisi, 0175, kostavas 69, saqarTvelo

reziume: minaboWkoTi daarmaturebuli betoni aris betonis kompoziciuri masala masSi Tanabrad ganawilebuli mokle minaboWkoTi. Sedegad, kompoziti gamoirCeva unikaluri TvisebebiT, rogoricaa simtkice, garemosadmi gamZleoba, nestisadmi mdgradoba, yinva-

gamZleoba, cecxlmedegoba. aseve minaboWkoTi daarmaturebuli betoni gamoirCeva simsu- buqiT da montaJis simartiviT. moyvanilia minaboWkoTi daarmaturebuli kompoziciuri masalis warmoebis da gamoyenebis ZiriTadi principebi, ganxilulia misi gamoyenebis sfero saqarTvelos bazarze. minaboWkoTi daarmaturebuli betonis gamoyenebis sfero moicavs rogorc dekoratiul, arqiteqturul elementebs, fasadis panelebs, aseve sakanalizacio xufebs da sadrenaJo sistemebs. aseve, ganxilulia axali kvlevebi da teqnologiebi mocemul kompoziciur masalasTan dakavSirebiT.

sakvanZo sityvebi: tutemedegi minaboWko; tutemedegi qsovilebi; meqanikuri Tvisebebi; warmoebis meTodebi; fasadis panelebi; dekoratiuli elementebi; boWko-betoni; boWkoTi daarmatureba.

DEVELOPMENT OF POROUS CALCIUM PHOSPHATE BONE SCAFFOLDS FOR DRUG DELIVERY D. Loca, J. Locs, K. Salma, L. Berzina‐Cimdina, V. Zalite, D. Vempere Riga Technical University, Riga Biomaterials Innovation and Development Centre, Pulka street 3/3, LV‐1007, Riga, Latvia

E‐mail: [email protected] have been developed for the preparation of calcium Resume: Synthetic calcium phosphates (CaP) are phosphate powders, which have to present desirable widely used as bone scaffolds due to their biocompatibil‐ characteristics, such as, crystallinity, stoichiometry, mor‐ ity and osteoconductive properties. To be used as drug phology, surface area particle size for specific applica‐ delivery systems, the pore structure of the scaffolds tions [7, 8]. All these properties are dependent on syn‐ needs to be controlled in terms of porosity, pore size and thesis method and its conditions. Physico‐chemical char‐ pore interconnectivity. acteristics of synthesized CaP have significant effect on In this research hydroxyapatite/β‐tricalcium phos‐ the final material quality (phase composition, density, phate biphasic mixture was synthesized by wet precipi‐ thermal stability, microstructure, mechanical properties, tation reaction. Porous bioceramics was obtained using dissolution behaviour and cellular response in living highly viscous/plastic mass foaming, where polyol was body) after thermal treatment. used as a liquid phase for the mass preparation and Mostly the CaP porous forms have been used as bone grafts to mimic the porous architecture of bone and to H4NHCO3 was used as a pore forming agent. Porous ce‐ ramics obtained had the total porosity in range from 30 provide appropriate space for bone ingrowths, pro‐ to 70 %. Gentamicin in porous bioceramic scaffolds was moted by interconnectivity of pores [9, 10]. Up to know incorporated using vacuum infiltration. Results ob‐ several methods for porous CaP bioceramics produc‐ tained demonstrated pore sizes in range from 60µm to tion have been developed: pyrolysis of organic par‐ 300µm in diameter, interconnectivity of pores, relative‐ ticles, foam sintering, gel‐casting, polymeric sponge ly dense pore walls and drug release within more than technique, coextrusion process, leaching, hydrothermal 6 hours. exchange, for instance using corals, marine inverte‐ brates, bicontinuous microemulsion technique, rapid prototyping techniques, freeze‐gel casing, foam‐gel Key words: bioceramics; bone scaffolds; drug deli‐ technique, sacrificial template method, direct foaming very systems; calcium phosphate ceramics. methods [11 ‐ 13]. Selection of the processing route for the production of porous ceramics depends primarily 1. INTRODUCTION on the final properties and application. To obtain por‐ The main driving force behind the use of CaP as bone ous structure, not only synthetic CaP, but also biogenic substitute materials throughout the body, covering all materials like bovine bone, corals and even wood are areas of the skeleton, is their chemical similarity to the used for bone graft production [14]. mineral component of mammalian bones and teeth [1, Bone replacement surgery usually is followed by high 2]. CaP is known to be osteoconductive and support os‐ systemic doses of antibiotic drug substances for pro‐ teoblast adhesion and proliferation, however, the brit‐ longed periods of time [15, 16]. This treatment is poorly tleness and low strength limit the CaP bioceramic wider selective, so that damage can occurs to the healthy tis‐ applications in hard tissue implants [3, 4]. sues and organs, different from the intended target [17, The development of biphasic calcium phosphate 18]. In addition, high drug doses is required to achieve (BCP) bioactive ceramics for bone implants involves con‐ the desired effect, thus implantable delivery tools, able trol of the process of biomaterial resorption and struc‐ to release the active substance in a controlled way and ture. The concept of this kind of bioceramics is based on local area are of clinical importance an optimum balance between more stable phase – hy‐ In the current research an approach to the fabrica‐ droxyapatite (HAp) and more soluble phase – β‐ tion of porous bone graft, exhibiting bone regeneration tricalcium phosphate (TCP) [5, 6]. Various synthesis function as well as the local drug delivery was made. routes, including wet chemical synthesis (such as precipi‐ tation, hydrothermal, hydrolysis and sol‐gel techniques)

2. THE BODY OF THE ARTICLE amounts of H4NHCO3 were added to the plastic mass as Materials and methods pore forming agent. Prepared mass was placed in cylindri‐ CaP powder used for bone graft preparation was cal moulds and then heated increasing temperature from prepared by a precipitation reaction between calcium 40 to 110 oC for proceeding the foaming process and par‐ hydroxide suspension (CaO, Riedel‐de Haën®, Germany) ticular release of organic additive from the sample. Sam‐ o and orthophosphoric acid solution (H3PO4, 85%, Sigma‐ ples were sintered at 1150 C for two hours. Ceramic Aldrich, Germany). Calcium oxide was suspended in dis‐ samples were investigated using X‐ray diffractometry tilled water and milled at rotation speed of 300 rpm with (XRD) and scanning electron microscopy (SEM). a Pulversette 5 planetary mill (Fritsch, Idar‐Oberstein Gentamicin sulphate (Sigma‐Aldrich) was used as a Germany) to obtain homogenous calcium hydroxide sus‐ model drug for drug delivery system (DDS) preparation. pension. The precipitation reaction took place in a 2 l re‐ Vacuum impregnation was applied for drug incorp‐ actor, equipped with stirrer, electrical heater with ther‐ oration in porous bioceramics. Release of gentamicin mostat, combined pH electrode and Titronic® system for was determined via thin layer chromatography method. acid solution addition. Acid solution was added to the calcium hydroxide suspension with slow addition rate Results and discussions ~0.75 ml/min under vigorous stirring. CaP were synthe‐ The effect of synthesis temperature and final pH on sized using appropriate synthesis conditions – pH of syn‐ the end product was examined by XRD. HAp/β‐TCP ratio thesis medium (pH 7,7) and temperature (45°C) The sus‐ in BCP ceramics was calculated using semi‐quantitative pension was aged for 20 hours at room temperature. Af‐ XRD analysis according to the intensities of the most in‐ ter aging the suspension was filtrated in a Buchner fun‐ tense diffraction peaks of HAp and TCP at 2θ=31.71° and nel and dried at 105°C. 31.03° respectively (see Fig. 1 a). SEM was used to evalu‐ The dried precipitate was milled to obtain a fine ate the microstructure of BCP bioceramics sintered at powder. To attain a highly viscous/plastic mixture, pow‐ 1100°C for 1h (see Fig. 1 b). der was mixed with liquid phase ‐ polyol. Different

Figure 1. BCP bioceramics (HAp/β‐TCP : 90/10): a) XRD patterns; b) SEM micrographs

The results showed that obtained BCP ceramic com‐ ranges from 28 to 70 %, while the open porosity is in prise of HAp/β‐TCP mixture in ratio 90/10 and forms range from 25 to 50%. Increasing amount of pore forming homogenous fine‐grained microstructure. agent, it was observed that the total porosity increased For the production of porous bone grafts, dry powder more rapid than the open one. As it is seen in SEM micro‐ after precipitation reaction was used. It was established photograph (see Fig. 2.b) porous bioceramic pore sizes are that by varying amount of pore forming agent in the plas‐ in range from 60µm to 300µm in diameter, pores are in‐ tic mass, it is possible to achieve different porosities after terconnected and pore walls are relatively dense. Pore sintering. The total and open porosity of porous bioceram‐ sizes and interconnectivity are sufficient for the porous ics obtained was determined using Archimedes method. bioceramics to be used as bone grafts. As seen in Fig. 2.a), the total porosity of bioceramics

Figure 2. Porous bioceramics: a) porosity dependence on amount of pore forming agent after sintering (total porosity – dashed line, open porosity – solid line); b) SEM microphotograph of fracture surface

To prepare local sustained release drug delivery sys‐ 0.5oC. Gentamicin was gradually released from bioceramic tem, the porous bioceramic scaffolds were impregnated scaffolds and after 1h of dissolution, 40% of active sub‐ with gentamicin water solution. Three impregnation stance was already transferred into the dissolution media. cycles were applied to obtain drug/BCP composite con‐ During the next five hours 70% of drug was released, but taining 9mg of gentamicin. In vitro drug release profile the maximum amount of gentamicin released in dissolu‐ was studied for 48h in simulated body fluid at 37oC ± tion media was reached within 30min (see Fig. 3).

Figure 3. Gentamicin release from CaP scaffolds

3. CONCLUSION arch in Biomaterials Technology of New Scientist Group”, The use of wet precipitation method for synthesis of No.2009/0199/1DP/1.1.1.2.0/09/APIA/VIAA/090. BCP at reported conditions leads to the formation of HAp/β‐TCP mixture in ratio of 90/10. References Highly viscous/plastic mass foaming is a perspective 1. S.V. Dorozhkin. Calcium Orthophosphates in Nature, method for the preparation of porous CaP ceramics. Obta‐ Biology and Medicine. Materials, 2(2009) 399–498. ined ceramics met the preconditions for the preparation 2. M. Vallet‐Regi. Ceramics for medical applications. J. of scaffolds for bone regeneration and local drug delivery. Chem. Soc., Dalton Trans. (2001) 97‐108. Gentamicin was gradually released from the bioce‐ 3. K. Ansalme. Osteoblast adhesion on biomaterials. ramic scaffolds and the drug release was sustainedfor Biomaterials, 21 (2000) 667‐681. more than 6 hours 70% of drug was released. 4. L.L. Hench, J. Wilson. An introduction to bioceramics. World Scientific, Singapore 1993. Acknowledgements 5. R. Z. LeGeros, S. Lin, R. Rohanizadeh, D. Mijares, J. P. This work has been partly supported by the European Le Geros. Biphasic calcium phosphate bioceramics: Social Fund within the project “Multidisciplinary Rese‐

preparation, properties and applications. J. Mater. Sci. 13. T.Y. Yang, J.M. Lee, S.Y. Yoon, H.Ch. Park. Hydroxya‐ ‐ Mater. Med., 14 (2003) 195‐200. patite scaffolds processed using a TBA‐based freeze‐ 6. T. Kokubo. Bioceramics and Their Clinical Applications. gel casting/polymer sponge technique. J. Mater. Sci: CRC Press, England, 2008. Mater. Med., doi 10.1007/s10856‐010‐4000‐1. 7. A. Bianco, I. Cacciotti, M. Lombardi, L. Montanaro. 14. A. R. Studart, U.T. Gonzenbach, E. Tervoort, L.J. Gau‐ Thermal stability and sintering behavior of hydroxya‐ ckler. Processing Routes to Macroporous Ceramic: A patite nanopowders. J. Therm. Anal. Cal., 88 [1] Review. J. Am. Ceram. Soc., 89 (6), (2006) 1771‐1789. (2007) 237–243. 15. J. Schniedersa, U.Gbureckb, R.Thullb, T. Kissela. Con‐ 8. M. Vallet‐Regí, J.M. Gonzáles‐Calbet. Calcium phos‐ trolled release of gentamicin from calcium phosphate‐ phates as substitution of bone tissues. Prog. Solid poly(lactic acid‐co‐glycolic acid) composite bone ce‐ State Chem., 32 (2004) 1–31. ment. Biomaterials, 27, (2006) 4239–4249. 9. W.J.E.M. Habraken, J.G.C. Wolke and J.A. Jansen. 16. I. Soriano, C.Evora. Formulation of calcium phos‐ Ceramic composites as matrices and scaffolds for drug phates /poly (d,l‐lactide) blends containing gentami‐ delivery in tissue engineering. Adv. Drug. Deliv. Rev. cin for bone implantation. Journal of Controlled Re‐ 59 (4‐5), (2007), p. 234‐248. lease, 68, (2000) 121–134. 10. H. Yoshikawa, N. Tamai, T. Murase and A. Myoui. 17. P.Balakumara, A.Rohillab, A. Thangathirupathia. Gen‐ Interconnected porous hydroxyapatite ceramics for tamicin‐induced nephrotoxicity. Do we have a promis‐ bone tissue engineering. J. R. Soc. Interface. 6 (2009), ing therapeutic approach to blunt it? Pharmacological p. S341‐S348. Research, 62, (2010) 179–186 . 11. D.M. Yunos, O. Bretcanu, A.R. Boccaccini. Polymer‐ 18. F.Galbusera, L.Bertolazzi, R.Balossino, G.Dubini. bioceramic composites for tissue engineering scaf‐ Combined computational study of mechanical beha‐ folds. J. Mater. Sci., 43, (2008) 4433‐4442. viour and drug delivery from a porous, hydroxyapa‐ 12. D.Shi. Introduction to Biomaterials. Tsinghua Univer‐ tite‐based bone graft. Biomech Model Mechanobiol. sity Press and World Scientific Publishing Co. Pte. Ltd, 8, (2009) 209–216. 2006, 13‐28.

forovani kalciumis fosfatis Zvlovani struqturis ganviTareba wamlis miwodebis mizniT d. loka, j. loksi, k. salma, l. berzina-cimdina, v. zalite, d. vempere rigis biomasalebis inovaciis da ganviTarebis centri, rigis teqnikuri universiteti. pulkas q. 3/3. LV_1007, riga latvia.

reziume: sinTetikuri kalciumis fosfatebi (CaP) farTod gamoiyeneba ZvalTan bioSeTavse- badobis da osteogamtarobis gamo. wamlis Sesayvan sistemad gamoyenebisas xdeba ConCxis forovani sistemis kontrolireba forianobis, forebis zomebis da urTierTkavSiris mixedviT. mocemul gamokvlevaSi hidroqsiapatiti β - trikalcium fosfatis orfaziani xsnari sinTezirebuliaAsveli daleqvis reaqciiT. forovani biokeramika miiReba zeblanti plas- tikuri masis aqafebiT, sadac polkoli gamoiyeneba, rogorc Txevadi faza masis mosamzadeblad da H4NHCO3 gamoiyeneba, rogorc forebis warmomqmneli reagenti. miRebuli forovani keramikis sruli forianoba 30-70% farglebSia. gentamicini forovan biokeramikul ConCxSi SeyavT vakumuri infiltraciis meTodiT. miRebulma Sedegebma gviCvena: forebis sidide 60_300 nm-mde diametriT, forebis urTierTkavSiri, SedarebiT mWidro forovani ke- deli da wamlis gamoyofa 6 saaTze meti xnis ganmavlobaSi.

sakvanZo sityvebi: biokeramika; Zvlis struqtura; wamlis Seyvanis sistema; kalcik fosfatis keramika.

UDC 669:621:762 THE RECEIVING AND STUDY OF HEMATITE NANOPARTICLES FOR HYPERTHERMIA G. Donadze*, G. Mamniashvili***, A. Akhalkatsi****, D. Daraselia****, D. Japaridze****, O. Romelashvili****, A. Shengelaia****, C. Gavasheli**** J.G. Heinrich**, Z. Kovziridze* *Department of Chemical and Biological Technologies, Technical University of Georgia, 77, Kostava str, Tbilisi, 0175, Georgia; ** Clausthal University of Technology, Institute of Nonmetallic Materials, Claustal – Zellerfeld, 38678, Zehntnerstrasse 2a, Germany; *** E. Andronikashvili Institute of Physics, Tamarashvili str. 6, Tbilisi 0162, Georgia; ****Exact and Natural Science Faculty, State University of Georgia, I. Chavchavadze Ave. 3, Tbilisi 0179, Georgia.

E‐mail: [email protected] ic field. The heat dissipated is consequence of the con‐ Resume: Microstructure of super nanoceramic par‐ version of the magnetic energy through different relaxa‐ ticles received in zeta potential equipment is studied by tion mechanisms, which depends on the physical proper‐ electronic microscopy and roentgenostructural analysis. ties of the magnetic particles. Particularly, in the case of Also, powder homogeneity, particle redistribution by size magnetic nanoparticles, the magnetic energy is converted and, respectively, stability and magnetic susceptibility to heat energy either by the resistive response of the rota‐ are studied by magnetometric method. tion of the magnetic particles (Brownian relaxation) or the Main technological parameters of α‐Fe2O3 receipt rotation of the magnetic moment within the particles are stated. Average sizes of particles are 30‐100 nm. The (Néel relaxation) to the alternating magnetic field. powder is homogeneous and in the process of analysis When the particles are in the nanometer size range, revealed good stability. Research object is super‐ the magnetic vectors in these particles vibrate and will paramagnetic. Relative value of its magnetic susceptibili‐ not stay static in the metastable state. Furthermore, ty is 1.00037. when these particles are dispersed in a low viscous sol‐ Sample magnetization measurements are done in vent, in addition to the spin rotation, the reversal of the cooling condition in zero magnetic field (ZFC) and cooling magnetic vector through particle rotation also has to be condition in nonzero field (FC), also magnetic hysteresis considered. However, even in free reversal through spin curves are measured at low and high temperatures com‐ rotation system, if the magnetic field alteration is rea‐ pared to the supposed blocking temperature (Tr) for lized at relatively very shorter times, the magnetic vector measured samples. is unable to respond quickly enough and consequently The existence of appreciable superparamagnetic con‐ the magnetic energy is dissipated as heat. And also, in tribution into magnetization against the background of vo‐ higher viscous liquids, particles could dissipate heat lumetric contribution connected with the existence of rel‐ through forced rotation due to magnetic torque under atively coarse micron particles such as residual magnetiza‐ strong magnetic fields. tion at cooling in zero field and magnetization jumps at Magnetic hyperthermia is a technique that proposes switching in of polarizing field in ZFC condition is estab‐ the annihilation of cancer cells through the elevation of lished. cell temperature above 316K by utilizing the heat dissi‐ From the state of maximum on curve ZFC it can be de‐ pated by magnetic particles exposed to an alternating duced that temperature of blocking in the given superpa‐ magnetic field.[1,2,3] The magnetic heating phenomenon ramagnetic subsystem of particles makes is a consequence of the response of magnetic particles

TB ~ 60 K. exposed to an alternating current (AC) magnetic field that converts the magnetic energy into heat energy. For exam‐ Key words: zeta potential, electronic microscopy, ple, when a magnetic field of strength larger than the roentgenostructural analysis, super paramagnetic, na‐ coercive force of a particle is applied in the direction op‐ nometer, agglomerate, stability, single‐domain, magnet‐ posite to the magnetic moment within the particle, the ic susceptibility. forced reversal of the magnetic moment occurs and Zee‐ man energy will be dissipated to the surroundings. 1. INTRODUCTION Nano particle that dissipates heat through Néel re‐ Magnetic fluid hyperthermia is a cancer treatment laxation is ideal for magnetic hyperthermia for two spe‐ technique that utilizes the heat dissipated by magnetic cific reasons. Firstly, there will not be any discrepancies nanoparticles exposed to an alternating current magnet‐ in heat dissipation characteristics of magnetite disper‐

37 sion between in vitro and in vivo analysis. Secondly, the conventional coprecipitation of divalent and trivalent magnetite particle that dissipates heat through Néel re‐ iron ions in alkaline media and thermal decomposition of laxation is small enough to be brought into dispersion organometallic compounds, and particles above 30nm and could be used for targeted delivery, which is an ad‐ through oxidation methods [8‐11] neither the synthesis ditional advantage of magnetic fluid hyperthermia. nor the heating characteristics of magnetite particles in The task is to receive single‐domain particles. In the the intermediate size range has been investigated in de‐ received particles domain structure disappears and they tail. represent single‐domain particles. The particles are of The idea of invention is that super nanoceramic par‐ such super high dispersivity that all elementary magnets ticles are received in zeta potential equipment. In this of all atoms there are arranged evenly, in parallel to each case iron chloride is used as electrolyte. Its 5% aqueous other and do not act against each other. The evident suspension is prepared and placed in 500 ml tank in phenomenon of the principle of “quantity to quality which a rotating cathode with polished surface – a round transition” is substantial change of magnetic properties iron plate is lowered from one side, and an iron plate – of particles at intense reduction of their sizes. It is known anode of the same area as the cathode is lowered from that at variation of magnetization domain boundaries another side. On the upper side of electrolyte an organic are changed. The direction of spontaneous magnetiza‐ 3 layer – toluene (density = 0.87 g/cm ) C6H5CH3 with less tion under the effect of variable magnetic field or do‐ specific weight is located which does not solve or mix in main vector and vector of external magnetic field is regu‐ water. 0.6‐0.7% monobasic oleic acid CH3(CH2)7CH= lated by us and causes the growth of domain sizes. It is 3 =CH(CH2)7COOH with density 0.825 g/cm is added to to‐ known that domain wall movement is hampered with: luene. This acid in upper organic layer promotes the ori‐ particle walls, inclusions, dislocations and other defects gination of adsorbed film on cathode and hampers crys‐ of lattice. This enables to move ceramic super particles tal particles growth on cathode. This film is characterized by means of variable magnetic field and certain stress of with high chemical stability and is determined with the field to the target or diseased cell which by receptors presence of reactive capacity carboxyl group. traps these ceramics. In a certain time, a certain amount The lower half of rotating cathode is submerged in of these super paramagnetics which are heated to 45 electrolyte while upper half is covered with toluene. This degree kills the cell. For the purpose of chemical selec‐ is necessary in order that iron ions extracted on the area tion, in order to make priority concentration of ceramic in cathode electrolyte at rotating be delivered to toluene super particles in tumor cell and not to damage healthy layer where as a result of cathode rotation there hap‐ cell, the modification of super nanoceramic particles sur‐ pens automatic removal of these ions with toluene, re‐ face is done by silanes, aminogroups, glucose‐like mat‐ sulting in toluene layer darkening which indicates ter, etc. [4‐7]. These particles do not damage healthy process finish. Voltage on the equipment is 25‐30 V, cur‐ cells but their protection is all the same needed. Healthy rent density + 0.5 A/dm2. As a result of current passing, cells endure comparatively high temperature. iron ions are emitted from anode. The difference of po‐

2. THE BODY OF THE ARTICLE tentials generated between the surface of the emitted The technical result of the work is the receipt of su‐ particle and dispersion area displaces the emitted par‐ per high dispersivity bio‐nanoceramic super paramagnet‐ ticles to cathode as iron ions are positively charged. The ics for creation of controlled local hyperthermia and particles are superposed on cathode. As a result of its ro‐ their purposeful transportation in living organism for ma‐ tation particles are brought up to toluene layer and re‐ lignant tumors treatment. moved with toluene. The extensive growth in activities associated with the After toluene layer is poured away and dried the par‐ potential use of magnetic nanoparticles in general and ticles are thermally treated above Curie temperature 0 0 magnetite particles in specific biomedical applications (769 C) at 770‐900 C in order that happen, on the one has triggered research on synthetics routes for particles hand, iron ions transition into paramagnetic state and, with well defined physical properties. It is well known on the other hand, oxidation and alpha iron oxide receiv‐ 0 that the size influences the specific absorption rates of ing. The mode of thermal treatment is 4‐5 C/min. magnetite and particles with sizes ranging between 40 The aim is to introduce these superceramic particles, received by us, into cells and their hyperthermia to 450 C (mono‐ to multi‐domain transition) and 10nm have been which is attained in following conditions: considered for magnetic hyperthermia. Although nano‐ particles below 10 nm could be synthesized through

1. The received superparamagnetics with formula α‐ as, by external factors – temperature, variable magnetic

Fe2O3 are dielectrics but they react on magnetic field and field – synergic effect on diseased cell. This phenomenon are heated to 43‐450C. Their average size is 30‐80 nano‐ is more effective with its action on diseased cell. meters. This is much less that the size of a cell (7‐10 µm) X‐ray analysis has been done on DRON‐3. On the first which allows to place their definite amount in the cell X‐ray interplanar spacings belong to α‐Fe2O3 (hematite); and to kill the cell. dhkl 3.690; 2.695; 2.520; 2.208; 1.837; 1.693; 1.625; 2. The introduction of such particles into a cell is faci‐ 1.505; 1.407 Å, while 3.20; 2.818; 2.288; 2.075 Å belong litated with magnetic field and diseased cell receptor – to chlorides. The second X‐ray of powder carried out folates which attract these particles and which are not with magnet where diffraction maximums of the sample present in healthy cells. belong only to hematite.

3. Particles are received on the basis of Fe2O3 and in At the Institute of Non‐Metal Materials of Technical compositions with its other type ceramics, such as mate‐ University of Clausthal, Germany, powder structure at rials with high concentration free electrons the spinal different magnification has been studied on SEM Cam magnetic moments of which contribute to paramagnet‐ Scan electron microscope. ism. Such compositions cause, by composition, as well

Distence to particles=8.0 mm; Signal A=SE1; Date: 12 Nov. 2009; Distence to particles=11.5 mm; Signal A=SE1; Date: 12 Nov. 2009; Expansion=100.00 KX; Voltage =20.00 kV. Expansion=50.00 KX; Voltage =20.00 kV.

Distence to particles=11.5 mm; Signal A=SE1; Date: 12 Nov. 2009; Expansion=20.00 KX; Voltage =20.00 kV.

Fig.1. Scanning electron‐microscopy representation of hematite agglomerates Fig.1 shows that hematite particles are mainly united which presumably were grown in the process of thermal into agglomerates. Several coarse particles are noticed treatment of powder above Curie temperature (8000 C).

Also, other particles are partially grown in the process of light scattering the characteristic values of particles dis‐ thermal treatment, as well as, in the process when iron tribution intensity was determined which is given in Ta‐ ions received in zeta potential equipment after being in ble 1. oxidizing medium of furnace transform into iron oxide. For example in the Table X50[nm] means that 50% of In order to characterize the intensity of particles dis‐ the total mass is particles in size less than 188.40 nm. tribution by size in powder the analysis was carried out The Table shows that three main factors of dispersivity at Powder House of Clausthal on “NANOPHOX” device. degree were determined: between 10‐60 nm, between Powder sample was introduced into 15 ml distilled water 100‐300 nm and over 600 nm. Almost 100% of powder is and for better dispersion during 15 min was treated with in size less than 2.434 µm. That means that at treating ultrasound. For the analysis of the material three iden‐ on zeta potential device built up by us and afterwards at tical dispersed samples were taken and measured. Then, treating on Curie temperature the particles of less size with the method of Photon Cross Correlation Spectros‐ are received which afterwards enables their introduction copy (PCCS) and based on dynamic physical principle of into cells and performing of hyperthermia.

Table 1 Important factors of distribution intensity

Sample x10[nm] x16[nm] x50[nm] x84[nm] x90[nm] x99[nm]

Hematite 140,14 149,17 188,40 1251,88 1529,92 2433,81 Fine part From ca. 10nm to 60nm Mode 1 Agglomerate 1 From ca. 100nm to 300nm Mode 2 Coarse Over ca. 600nm Mode 3

Qint/%

distribution,

Total

Particle Size, nm

Fig. 2. Accumulation curve of hematite particles distribution

Qint

distribution

size

Grain

Particle Size, nm

Fig. 3. Hematite particles distribution

These particles are of single domain. Magnetic suscep‐ Gauss distribution (Fig. 3) was determined. The Figures tibility of the received single‐domain α‐Fe2O3 has been show that in powder the particles of size less than 100 studied with vibrating magnetometric method in 10 kE nm is about 5% while that of 100‐300 nm ‐ 62‐63% which voltage magnetostatic field. Magnetic field is created on mainly coincides with the data of Table 1. FL‐2 type magnet. The researched object is shown to be Complex curves have been constructed for all three paramagnetic. Relative magnitude of magnetic susceptibil‐ parts of the existing powder (Fig. 4). The Figures show ity of these superparamagnetics is 1.00037. that complex curves of all three samples are almost With NANOPHOX device accumulation curve of par‐ identical. The third sample shows a slight difference. ticle distribution (Fig. 2) and particle density – normal

/ Qint(x)

Qint(x)

distribution,

size

distribution,

Grain Total

Particle Size, nm

/ Qint(x)

Qint(x)

distribution,

size

distribution,

Grain Total

Particle Size, nm

Qint(x)

distribution,

size

distribution,

Grain Total

Particle Size, nm

Fig. 4. Complex curves of particle distribution by size for all three samples of powder

relation / % r Co

Fig. 5. Diagram of powder correlation

Fig. 5 shows graphical representation of powder sta‐ From the state of maximum on curve ZFC it can be de‐ bility analysis. In the process of analysis powder showed duced that temperature of blocking in the given superpa‐ homogeneity, uniform distribution by size and, respec‐ ramagnetic subsystem of particles makes TB ~ 60 K tively, good stability. FC curve is characteristic for the corresponding super‐ Magnetic measurements were done on the samples of paramagnetic powders at strong interaction between par‐ powdery hematite placed in standard plastic capsules of ~ 5 ticles. mm size. Measuring was done on vibrating magnetometer This solution is confirmed also by the result of analysis Cryogen Free Mini VSM (Cryogenic limited) within tempera‐ of hysteresis curves measured before (a) and after block‐ ture range 2‐293 К and in magnetic fields up to 2T. ing temperature Тв (T=3 К and T=160 K), respectively. Sample magnetization measurements are done in At higher temperatures coercive force is substantially cooling condition in zero magnetic field (ZFC) and cooling lower than in the first case, but it is not zero as is in case condition in nonzero field (FC), also magnetic hysteresis for superparamegnetic systems. curves are measured at low and high temperatures com‐ pared to the supposed blocking temperature (Tr) for measured samples. The results of measuring of magnetization are pre‐ sented in Fig. 6‐7. XFC condition in field H=30 Oe FC condition in field H=30 Oe. The comparison of the results of analogous measuring made on nano particle powdery samples of hematite [12] with average size of nanoparticles 0~ 3 nm allow to make a solution about the existence of appreciable superpara‐ magnetic contribution into magnetization against the background of volumetric contribution connected with the existence of relatively coarse micron particles (see Fig.3) showing grain size distribution, such as residual magnetization at cooling in zero field and magnetization jumps at switching in of polarizing field in ZFC condition.

Fig. 7. Hysteresis curves of hematite (Fe2O3) sample at a) T=3 K and b) T=160 K temperatures

3. CONCLUSION After further treatment of iron ions received in zeta potential equipment at higher (8000C) than Curie tem‐ perature (7690C) with the regime 4‐50C/min hematite particles of 30‐100 nm size were obtained in oxidizing medium. Electron microscope analysis proved that these articles are agglomerated. NANOPHOX device registered agglomerated whole particle which increased average size of grains in powder and determined it at the average of 195 nm. Fig. 6. Temperature dependence of magnetization of hematite Sample magnetization measurements are done in (Fe2O3) powder: a) field‐cooled (FC) at 30 G; cooling condition in zero magnetic field (ZFC) and cooling b) zero‐filed‐cooled (ZFC) at 30 G; c) cooled at zero field condition in nonzero field (FC), also magnetic hysteresis

43 curves are measured at low and high temperatures com‐ 4. M. Kawashita, Z.Li, N.Araki, M.Mitsumori, M. Hiraoka, pared to the supposed blocking temperature (Tr) for “Fe3O4‐containing SiO2 mikrospheres for Hiperther‐ measured samples. mia of Cancer”, 34rd International Conference and The existence of appreciable superparamagnetic con‐ Exposition on Advanced Ceramics and Composites, tribution into magnetization against the background of vo‐ January 23‐27, 2010, Daytona Beach, Florida, USA. lumetric contribution connected with the existence of rel‐ 5. M. Kawashita, M. Tanaka, T. Kokubo, T. Yao, S. Ha‐ atively coarse micron particles (see Fig. 3) such as residual magnetization at cooling in zero field and magnetization mada and T. Shinjo, "Preparation of magnetite micro‐ jumps at switching in of polarizing field in ZFC condition is spheres for hyperthermia of cancer," Key Eng. Ma‐ astablished. ter., 218‐220, 645‐648 (2002). From the state of maximum on curve ZFC it can be de‐ 6. Z. Li, M. Kawashita, N. Araki, M. Mitsumori, M. Hirao‐ duced that temperature of blocking in the given superpa‐ ka and M. Doi, "Preparation of magnetic iron oxide ramagnetic subsystem of particles makes nanoparticles for hyperthermia of cancer in a FeCl2‐ TB ~ 60 K NaNO3‐NaOH aqueous system", J. Biomater. Appl., in press. ACKNOWLEDGEMENTS 7. M. Kawashita, R. Araki and G. H. Takaoka, "Induction We thank Powder House (Pulver Hous) of Clausthal, of bioactivity on silicone elastomer by simultaneous Germany, for performed interesting research and assis‐ tance. Also we thank Tbilisi Medical Center of Oncology irradiation of oxygen cluster and monomer ion for material submitted. beams," Acta Biomater., 5, 621‐627 (2009). 8. T. Sato, IEEE Trans. Magn., 6, 795799 (1970). References 9. S. Sun and H. Zeng, J. Am. Chem. Soc., 124, 1. P. Wust, B. Hildebrandt, G. Sreenivasa, B. Rau, J. Gel‐ 82048205 (2002). 10. T. Sugimoto and E. Matijević, J. Colloid Interface lermann, H. Riess, R. Felix and P. M. Schlag, Lancet Sci., 74, 227243 (1980). Oncol., 3, 487489 (2002). 11. M. Tada, S. Hatanaka, H. Sanbonsugi, N. Matsushita 2. P. Moroz, S. K. Jones and B. N. Gray, J. Surg. Oncol., 77, and M. Abe, J. Appl. Phys., 93, 75667568 (2003). 259269 (2001). 12. JMMM 244 (2001) 5‐11, 37‐44 3. B. Jeyadevan. Present status and prospects of magne‐ tite nanoparticles‐based hyperthermia. Journal of the Ceramic Society of Japan 118[6] 391‐401, 2010.

uak 669:621:762 hematitis nanonawilakebis miReba da kvleva hiperTermiisaTvis g. donaZe*, g. mamniaSvili***, a. axalkaci****, d. daraselia****, d. jafariZe****, o. romelaSvili****, a. Sengelaia****, c. gavaSeli****, i. hainrixi**, z. kovziriZe* *qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi 0175, kostavas 69, saqarTvelo; **klausthalis teqnikuri universiteti, klaustal-cellerfeldi, celtnerStrase 2a, germania; ***andronikaSvilis fizikis instituti; TamaraSvilis 6, Tbilisi 0162, saqarTvelo; ****zust da sabunebismetyvelo mecnierebaTa fakulteti, saqarTvelos saxelmwifo universiteti, WavWavaZis 3, Tbilisi 0179, saqarTvelo.

reziume: Seswavlilia Zeta potencialis xelsawyoSi miRebuli superparamagnetikuri nawilakebis mikrostruqtura, eleqtronuli mikroskopiTa da rentgenostruqturuli anali-

44 ziT. aseve, Seswavlilia fxvnilis homogenuroba, zomebis mixedviT nawilakebis gadanawi- leba, Sesabamisi stabiluroba da vibraciuli magnitometruli meTodiT magnituri amTvi- sebloba. dadgenilia α-Fe2O3-is miRebis ZiriTadi teqnologiuri parametrebi. nawilakebis saSualo zomebi 30_100 nm-ia. fxvnili homogenuria da analizis procesSi kargi stabiluroba aCvena. kvlevis obieqti superparamagnetikia. misi magnituri amTviseblobis fardobiTi sidide 1,00037 Seadgens. nimuSebis damagnitebis gazomvebi Seswavlilia gacivebis reJimSi nulovan magnitur velSi (ZFC) da gacivebisas nulisagan gansxvavebul magnitur velSi (FC), agreTve gazomi- lia magnituri histerezisis mrudebi dabali da maRali temperaturebis dros nimuSebis gasazom SemoTavazebul blokirebis temperaturasTan (ТВ) SedarebiT. dadgenilia, damagnitebaSi ufro msxvili nawilakebis moculobiTi wvlilis fonTan SedarebiT, mniSvnelovani superparmagnituri wvlilis arseboba - rogoricaa narCeni da- magniteba nulovan velSi gacivebis dros da damagnitebis naxtomi mapolarizebeli velis CarTvisas ZFC reJimSi. ZFC mrudze maqsimumis adgilis mixedviT SesaZlebelia daskvnis gamotana, rom blokirebis temperatura mocemul superparamagnitur qvesistemaSi Seadgens ТВ ~ 60 K.

sakvanZo sityvebi: Zeta potenciali; eleqtronuli mikroskopia; rentgenostruqturuli analizi; superparamagnetiki; nanometri; aglomerati; stabiluroba; erTdomeniani; magnituri amTvisebloba.

UDC 539; 541.1 COLLOIDAL GOLD AND ITS USE IN MEDICINE N. Kobaladze**, N. Bibiluri*, L. Kristesashvili*, N. Chkhubianishvili** *Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava Str, Tbilisi 0175, Georgia; **L. Samkharauli National Bureau of Legal Expertise 84, Chavchavadze Av., Tbilisi 0162, Georgia

E‐mail: [email protected] tive effect of colloidal gold is noted at blood circulation Resume: Colloidal gold is gold nano particles col‐ system dysfunction. loidal solution in demineralized water. It has no odor and taste. Gold particles have similar charges and are in sus‐ Key words: colloidal gold; nano particle; alcohol; cell. pended state. From the ancient times gold was used with the pur‐ pose of health improvement. Different from colloidal sil‐ 1. INTRODUCTION ver, colloidal gold has no bactericidal properties but it Gold positively acts on thermoregulation mechanism, stabilizes nervous system, helps normal activity of mind, particularly, in cases of chill, malaria, profuse sweating restores internal harmony in persons with unstable when sleeping. It is noted that use of colloidal gold de‐ psyche (mainly, depression state, suicidal attempt). Posi‐ creases alcoholic dependence and suppresses the hun‐ ger for alcoholic drinks.

2. THE BODY OF THE ARTICLE

Scheme of preparation of colloidal gold solution

Table Preparation of colloidal gold solution

# Preparation stages Amount Dissolution of gold I 1. Au /999.9/ purity 0.05g 2. HCl – conc. 3 ml

3. HNO3 – conc. 1 ml

Evaporation to wet waste

II 1. H2O – dist. 5 ml. 2. HCl – conc. drop – by ‐ drop

Preparation of 0.01% HAuCl4 solution

III 1. H2O – dist. 500ml

1% citric acid sodium sult solution (Na3C6H5O7)

IV 1. Na3C6H5O7 1g

2. H2O – dist. 99 ml

Preparation of colloidal gold solution

V 1. 0.01% ‐ HAuCl4 20 ml

2. 1% ‐ Na3C6H5O7 2 ml 3. 1% ‐ NaCl solution /2‐3/ dr. drop – by ‐ drop

The method of preparing of colloidal gold. with the help of colloidal gold and prolongation of life of In order to prepare 0.5 l colloidal gold, first is pre‐ such patients. The searches in this sphere are in pared 0.01% HAuCl4 solution. We take 0.05 g 999.9 puri‐ progress. ty gold, dissolve it in acid mixture: 1) conc. HCl ‐3 ml, 2) The mechanism of colloidal gold action is not yet conc. HNO3 ‐1 ml. After solving ∼ 5 ml distilled water is stated, similar to all other spheres where it is used in added and placed on water bath for evaporation. In the medical purposes. process of evaporation we add conc. HCl in drops up to In old Egypt pharaohs took gold into organism to removal of nitrogen oxide. The mixture is evaporated to heighten tonus. While in Middle Ages Paracelsus used wet residual which is solved in 500 ml distilled water. gold and silver for preparation of drugs. For the first time The prepared solution is stored in green glass vessel. colloidal gold in pure form was received by M.Faraday. Separately is prepared 1% citric acid sodium salt solu‐ While in 1890 doctor R.Koch discovered that tubercles tion (Na3C6H5O7). bacilli (Koch bacillus) lost their viability in the presence of

For receiving colloidal god 20 ml 0.01 % HAuCl4 solu‐ gold. From the end of XIX century in the USA colloidal tion is put into 50 ml volume Erlenmeyer flask and added gold was used as the main antialcoholic means. From the

2 ml 1% Na3C6H5O7 solution, boil ~5‐15 min. For protec‐ same time it was used for medication of arthritis, skin tion of Clˉ –ions in the process of boiling add 2‐3 drops ulcers, burns and other diseases. of 1% NaCl solution. Boil until receiving dark red color. Colloidal gold increases life tonus, stimulates organ‐ (nano particles size: 5‐50 nm). After cooling it is used in ism’s restoring function, increases the resistance to dif‐ medical purposes. This is a daily standard. The course of ferent diseases and can be used in the following cases: treatment with this solution is 25 days. ‐ Depression (fear, despair, prostration, suicidal at‐ Simultaneous taking of colloidal gold and colloidal sil‐ tempt, etc.); ver strengthens organism capacity to oppose diseases, ‐ Blood circulation system dysfunction; helps rejuvenation and preservation of life tonus. There ‐ Digestive system dysfunction; is information about suppression of cancer cells growth ‐ Alcohol dependence;

‐ After chill diseases; system inflammatory diseases. It improves the func‐ ‐ Skin ulcers; tion of suprarenal glands, increases immune status of ‐ Arthritis; organism. ‐ Burns. The urgency and interest to the theme makes the Besides, colloidal gold strengthens cells regeneration scientists to continue researches in the mentioned direc‐ process and purifies organism from residues. tion and to see to the problem of foundation of the re‐ As an agent for external use it is used as analgesic, spective base in Georgia. helps to quick healing of wounds and other skin inju‐ ries. In order to get double effect it can be used to‐ References gether with colloidal silver. There are no contraindica‐ 1. http://probio.io/ru/catalogue/mag2/250. Golden‐ tions revealed. max, Colloidal gold. 2. http://www biotest.ru/ru/technology. 3. http://www, chemport.ru/guest 2/viewtopic.phpf= 3. CONCLUSION 108¢=19368. Colloidal gold in the form of biologically active ad‐ 4. http://rapidshare.com/files/96924603/2 rar.html. dition (BAA) helps the normalization of urogenital sys‐ 5. http:/www,lifepac,narod.ru/zoloto.htm. tem functioning. It is recommended in case urogenital

uak 539; 541.1 koloiduri oqro da misi gamoyeneba medicinaSi n. kobalaZe**, n. bibiluri*, l. qristesaSvili*, n. CxubianiSvili* *qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, kostavas 69, Tbilisi, 0175, saqarTvelo; **l. samxaraulis sasamarTlo eqspertizis erovnuli biuro, i. WavWavaZis gamziri. 84, Tbilisi 0162, saqarTvelo.

reziume: koloiduri oqro warmoadgens nanonawilakebis koloidur xsnars deminerali- zebul wyalSi. ar aqvs suni da gemo. Ooqros nawilakebi atarebs erTsaxelian muxts da im- yofeba Sewonil mdgomareobaSi. uZvelesi droidan oqros gajansaRebis mizniT iyenebdnen. koloiduri vercxlisagan gansxvavebiT, koloidur oqros ar aqvs baqtericiduli Tvisebebi, magram astabilizebs nervuli sistemis mdgomareobas, xels uwyobs normalur gonebriv saqmianobas, aRadgens Sinagan harmonias aramdgradi fsiqikis mqone adamianebSi (ZiriTadad, depresiuli mdgoma- reoba, suicidis mcdeloba). koloiduri oqros dadebiTi zegavlena aRiniSneba sisxlis mi- moqcevis sistemis funqciis moSlis dros.

sakvanZo sityvebi: koloiduri oqro; nanonawilaki; alkoholi; ujredi.

UDC 666.95 INVESTIGATION OF THE POSSIBILITY OF BARIUM CONTAINING CLINKER PRODUCTION USING VOLCANIC ROCKS E. Shapakidze, V. Maisuradze, M. Nadirashvili, O. Melkadze, S. Kavtaradze, M. Tkemaladze Caucasian Alexander Tvalchrelidze Institite of Mineral Resources, 85, Paliashvili st., Tbilisi, 0162, Georgia.

E‐mail: [email protected] +2 process of high temperature burning is known [1,2]. Ba +2 Resume: One of the major tendencies of cement ions characterized with high activity expel Ca from production and building industry development is the de‐ clinker minerals crystalline lattice, which, in its part, is crease of energy consumption. As 80% of total power used for saturation of two‐calcium silicate (bellite) to tri‐ consumption comes on clinker burning, the main effort calcium silicate (allite). Therefore, in barium containing should be directed on power economy. cements the increased amount of tricalcium silicate is One of the means to achieve this objective is using of fixed compared to theoretical one. Allite is distinguished small additives, the so‐called mineralizers, modifying and with higher hydraulic activity than bellite. alloying additives. When studying barium containing clinkers the deficit Volcanic rocks which provide the receipt of barium material – viterite or barium ore with high barium con‐ containing clinkers was used as an additive. tent was, in most cases, used as mineralizer and alloying additive, which is economically ineffective. At the same time the works have been carried out [3] Key words: barium containing clinker; mineralizer; when for receiving barium containing clinkers the wastes modifying agent; alloying additive; volcanic rocks. of the Kutaisi lithopone works have been used where BaSO content achieves to about 60%. In authors’ opi‐ 1. INTRODUCTION 4 nion, in 0.3‐0.5% BaO clinker, this is the amount when The analysis of contemporary tendencies of cement the maximum of burning temperature decrease and production development proved that parallel to power clinker activity increase is achieved. consumption decrease the elaboration of technologies of At present the mentioned works is not operating and receiving of highly active cements is of priority. consequently, there are no wastes. One of the means to achieve this objective is usage of In this respect our interest was attracted by quartz‐ small additives of the so called mineralizers, modifying adular metasomatites (QAM), the overlapping rocks of and alloying additives which can effect on clinker forma‐ barite ore in David Gareji, South‐East Georgia, which in tion processes and cement structure creation. previous years became the subject of serious investiga‐

tion of Caucasian Institute of Mineral Resources as the 2. THE BODY OF THE ARTICLE raw material source for bottle glass production [4]. As a rule, P2O5, Cr2O3, SO3, Na2O, K2O, BaO, SrO, CdO, Geological researches showed that overlapping rocks MnO, TiO2, FeO, MgO and other oxides are considered as of the David Gareji barite ore are presented with volcan‐ mineralizers, modifying and alloying additives to cement ic rhyolite composition fragmentary tuffs. Metasomati‐ charge small amounts of which are present in clinker cally transformed tuffs are built of effusion, pumice, or‐ composition and the mechanism and character of their thoclase (common potash feldspar) and plagioclase action often stay unknown. At the same time, simulta‐ fragments. Effusion fragments are presented with biotite neous coexistence of several elements effects on the and hornblende‐biotite rhyolites the main mass of which level of efficiency of each of them and makes more com‐ is substituted with fine aggregate quartz. plicated the problem of investigation of the effect of mi‐ The overlapping rocks are enveloping barium ore re‐ cro additives. sulting in all around distribution of various intensity bari‐ Different researchers note positive effect of BaO on tization process in these rocks. Barium sulfate content the growth of clinker strength which proves that barium changes in average from 5 to 20% which corresponds to is an effective “activator” of clinker hydration activity 3‐12% of BaO and 1.6‐7% of SO which, in its part, ap‐ and mechanical strength. The role of BaO, as that of ce‐ 3 pears as mineralizing agent. In the content of other ment clinker minerals alloying and modifying oxide in the

oxides these rocks in their chemical composition (Table For charge composition limestone from Dedoplis‐ 1) are close to the composition of clayey component Tskaro, clay and iron cinders from Rustavi were used used in cement industry. Because of this their usage in (Table 2). For comparison a control charge No 1 was this direction is quite logical [5]. At the same time, in vol‐ composed which was prepared on the basis of tradition‐ canic rocks SiO2 content is higher than in clay which is al raw material, only (Table 3). the guarantee of the increase of clinker silicate module and cement physical‐mechanical indices. Table 1 Chemical compositions of barium containing QAM

QAM The content of oxides, mas %

No L.O.I. SiO2 Al2O3 Fe2O3 CaO MgO SO3 BaO R2O 1 0.21 79.00 7.93 0.56 0.13 1.32 1.92 3.28 5.36

2 0.48 76.80 6.80 0.43 0.22 1.02 3.42 5.69 5.11

3 0.15 72.80 8.32 0.56 0.15 0.54 4.05 7.75 5.41

4 0.11 71.52 7.22 0.49 0.17 1.21 5.11 9.79 4.33

5 0 68.06 7.12 0.46 0.22 0.31 6.31 12.09 5.42

Table 2 Chemical compositions of raw components

The content of oxides, mas % The name of components L.O.I. SiO2 Al2O3 Fe2O3 CaO MgO SO3 R2O

Limestone 42.03 0.36 0.33 0.10 55.12 1.24 0.12 0.20

Clay 14.10 42.38 13.37 5.01 15.43 1.54 0.10 2.01

Iron cinders 0 14.81 5.45 74.49 2.27 1.53 0.56 0.00

Table 3 Matter compositions of charges

The content of raw components, mas %

Charge No Limestone Clay Iron cinders QAM

1 68.70 28.84 2.45 _

2 70.97 22.41 2.29 4.34

3 70.73 22.78 2.26 4.23

4 70.88 21.79 2.31 5.02

5 70.64 22.29 2.28 4.79

6 70.51 22.10 2.28 5.11

Clinkers were burned in laboratory high temperature furnace. The quality of burning process end was checked ac‐ cording the content of free CaO (Fig. 1).

Fig.1. Kinetics of free CaO binding according to BaO content in clinkers and burning temperature

The experiments proved that for control charge No 1 complication of sintering and increase of burning tem‐ optimum temperature of burning is 14000C while at in‐ perature but due to the effect of BaO and presumably of troduction of QAM into charge (which ensures definite SO3 the burning of the mentioned charges happens at content of BaO, see Table 4) there happens the decrease lower than reference temperature. of maximum burning temperature by 30‐700C. Optimum The increase of relative share of silicates provides use of free CaO happens in charges No 3, No 4 and No 5 high mechanical strength of the cements prepared from which corresponds to 0.36, 0.58 and 0.7 % BaO in clink‐ these clinkers. Besides, as it was mentioned above, with ers. When BaO content grows to 0.92%, charge becomes substitution of Ba+2 for Ca+2 ions in clinker silicate crystal‐ high‐sintered though compared to additive‐less (No 1) line lattice the growth of tricalcium silicate amount com‐ charges its burning temperature is lower by 300C. pared to theoretical one is achieved, which is one more Chemical compositions of test charges and clinkers additional reserve of improvement of physical‐mecha‐ prepared from them are given in Table 4. nical properties of cement. Theoretical mineralogical composition of control The action mechanism of BaO as modifying agent is clinker No 1 is: that it forms solid solutions with clinker minerals which

C3S = 54 %; C2S = 18%; C3A =9 %; C4AF = 16 %. are proved with the curves of clinkers X‐ray phase analy‐ That of clinkers received with QAM addition: sis (Fig.2) where it is clearly seen that main peaks are

C3S = 56 %; C2S = 19%; C3A =8 %; C4AF = 14 %. displaced in barium containing clinkers, besides, the As it is obvious the introduction of QAM into clinker peaks acquire diffusion character. In this case there hap‐ material charge composition causes the growth of cal‐ pens stabilization of allite high temperature (triclinic) cium silicates amount which is conditioned with high modification which is distinguished with high activity content of silicates in KAM compared to clay. The in‐ compared to low temperature (monoclinic) modification crease of silicate module in charge should have caused (Fig.3).

Table 4 Chemical compositions of charges/clinkers, mas%

No L.O.I. SiO2 Al2O3 Fe2O3 CaO MgO SO3 BaO R2O KH n p 33.35 13.63 4.47 3.45 42.85 1.37 0.13 ‐ 0.76 1 0.9 1.7 1.29 – 20.45 6.70 5.18 64.30 2.05 0.19 – 1.13 33.35 14.14 3.90 3.01 43.05 1.34 0.21 0.14 0.86 2 0.9 2.05 1.29 – 21.22 5.84 4.51 64.60 2.02 0.31 0.21 1.28 33.32 14.12 3.89 3.00 42.98 1.33 0.27 0.24 0.85 3 0.9 2.05 1.29 – 21.18 5.83 4.51 64.46 2.00 0.40 0.36 1.27 33.22 14.10 3.88 3.00 42.90 1.30 0.33 0.39 0.88 4 0.9 2.05 1.29 – 21.11 5.81 4.49 64.25 1.95 0.49 0.58 1.32 33.19 14.08 3.88 3.00 42.86 1.34 0.37 0.47 0.83 5 0.9 2.05 1.29 – 21.07 5.80 4.48 64.15 2.00 0.55 0.70 1.24 33.10 14.05 3.87 2.99 42.75 1.29 0.44 0.62 0.89 6 0.9 2.05 1.29 – 20.99 5.78 4.47 63.90 1.93 0.66 0.92 1.33

Thus, several theoretical factors stipulate high me‐ 2700‐3000 cm2/g specific surface. The paste of normal chanical strength of cements received with QAM addi‐ consistency was prepared from the received cements tion which was proved with further tests. and molded into 2x2x2x cm blocks which were hardened Clinkers were powders in laboratory ball mill with in water and testes on laboratory hydraulic pressure. The addition of 5% natural gypsum up to achievement of results are presented in Table 5.

Fig. 2. X‐ray patterns of clinkers burned at optimum temperature

Fig.3. Diagnostic reflexes of allite in clinkers according to burning temperatures

Table 5 The results of physical‐mechanical tests of cements

Quantity of the add‐ Hardening times, Hour‐ Minute Compressing strength, Mpa No ed water, % Start Finish 3 days 7 days 28 days

1 28 2 ‐ 20 3 ‐ 45 56 61 95

2 28 2 ‐ 20 3 ‐ 30 55 69 98

3 28 2 ‐ 30 3 ‐ 55 62 78 110

4 27.5 2 ‐ 15 4 ‐ 05 68 83 112

5 27.5 2 ‐ 25 3 ‐ 55 65 80 109

6 28 2 ‐ 20 3 ‐ 50 57 67 99

As is seen from tests, cements No 3, 4 and 5 (0.36, which evidently should cause high strength of cement 0.58 and 0.7% BaO composition, respectively,) are cha‐ No 1 at early period of hardening (3 days). Though the racterized with higher mechanical indices on all stages of results of physical‐mechanical tests prove the opposite – hardening compared to control cement (No 1). Cements barium containing clinkers are characterized with higher No 2 and No 6 (0.21 and 0.92% of BaO content, respec‐ mechanical strength at all stages which is explained with tively) in indices, little but nevertheless exceed that of modifying and alloying action of BaO. control one which presumably is conditioned with high silicate module of clinker and respectively, with increase 3. CONCLUSION of silicate mineral share. Thus, QAM addition to clinker charge composition

In control clinkers sum of C3A+C4AF minerals is 25 % ensures the decrease of clinker burning temperature by while in clinkers received with addition of QAM – 22% 50‐700C and increase of early (3 days), as well as, brand

(28 days) strength of cements compared to clinkers pre‐ of Cement. Moscow, StroiIzdat, 1976, p.132‐153 (in pared on traditional raw materials. Under the received Russian). results the existence of 0.3‐0.7% BaO in clinker may be 3. K.B.Tandilova, M.M.Sichov, V.N.Minkina. Barium con‐ considered optimum. It should be noted that receiving of taining wastes ‐ mineralizing additive in clinker pro‐ barium containing clinkers is possible using local not duction. Cement, 1982, No 3 (in Russian). scarce volcanic rocks. 4. L. Gabunia, G. Nadareishvili, I. Gejadze, E. Shapakidze, O. Machavariani, M. Tkemaladze, S. Kavtaradze. Over‐ References burden rocks of David Gareji‐Mushevani deposit as 1. I.I. Kholin, Z.B. Entin, YU.C. Malinin. On interaction of the raw material for glass industry in Georgia. Ma‐ βC2S and C3S with barium oxide. Scientific works of terials of II Intenational Conference of Ceramists’ As‐ NIIcement, Moscow, Gosplanizdat, 1961, No 10(41), sociation of Georgia, Tbilisi, 2009, p.151‐154 (in Rus‐ p.24‐29 (in Russian). sian). 2. Yu. M.Butt, V.V. Timashev, A.P. Osokin. Mechanism of 5. E.Shapakidze, G.Nadareishvili, V.Maisuradze, M. Na‐ clinker formation processes and modification of its dirashvili, M.Tkemaladze. Perspectives of using of ba‐ structure. In: VI International Congress in Chemistry rite ore overburden rocks of David Gareji deposit. LELP CIMR collection. Tbilisi, 2009, p. 412‐415.

uak 666.95 bariumSemcveli klinkerebis miRebis SesaZleblobebis kvleva vulkanuri qanebis gamoyenebiT e. SafaqiZe, v. maisuraZe, m. nadiraSvili, o. melqaZe, s. qavTaraZe, m. tyemalaZe kavkasiis aleqsandre TvalWreliZis mineraluri nedleulis instituti, faliaSvilis q. 85, Tbilisi, 0162, saqarTvelo.

reziume: cementis warmoebis da samSeneblo industriis ganviTarebis erT-erTi mTavari tendencia energodanaxarjebis Semcirebaa. vinaidan saerTo energetikuli danaxarjebidan 80% modis klinkeris gamowvaze, mTavari Zalisxmeva mimarTuli unda iyos energiis ekono- miaze. am miznis misaRwevad erT-erTi mTavari saSualebaa mcire danamatebis e.w. minerali- zatorebis, modificirebuli da malegirebeli danamatebis gamoyeneba. aseT danamatad mocemul naSromSi gamoyenebulia vulkanuri qanebi, romlebic uzrunvelyofen bariumSemcveli klinkerebis miRebas.

sakvanZo sityvebi: bariumSemcveli klinkeri; mineralizatori; modifikatori; malegirebeli danamati; vulkanuri qanebi.

UDC 669:621:762 IMPROVEMENT OF BORON CARBIDE MECHANICAL PROPERTIES IN B‐C‐Ti SYSTEM A Z. Mestvirishvili*, J.Heinrich**, Z.Kovziridze* *Department of Chemical and Biological Technology, Georgian Technical University, 69 Kostava str., Tbilisi 0175 Georgia; **Technical University of Clausthal, Institute of Nonmetalic Materials, Clausthal-Zellerfeld, Zehntnerstrasse 2a, Germany.

E‐mail: [email protected]

Resume: Experimental works have been conducted the objective of which was to improve mechanical proper‐ ties of boron carbide by introduction of doping element in‐ to the system. Titanium was selected as a doping element, which was introduced into the system in the form of TiB2. Four types of boron carbide ‐ titanium mixture with various titanium diboride content were used in experiments. Op‐ timal process parameters, as well as doping element con‐ centration, necessary to provide required high mechanical parameters in the composite were defined.

Key words: boron carbide; titanium diboride; hard‐ Fig. 1. Crystal structure of boron carbide ness; fragility; impact elasticity; hot pressing; composite; doping. 2. THE BODY OF THE ARTICLE Samples of pure boron carbide and boron carbide 1. INTRODUCTION containing titanium diboride were prepared. The mix‐ Due to outstanding features of its basic component, tures were prepared from boron carbide and titanium boron, boron carbide (B4C) finds wide application in vari‐ diboride powders produced by H.C.Starck GmbH (Ger‐ ous fields, in particular, due to its unique nuclear fea‐ many). Boron carbide powder specifications are pre‐ tures it is widely used in control rods of nuclear power sented in Table 1. plants as neutron absorbing material, as hard material Quantities of powder forming mixtures were selected (9.35 by Moos scale) it finds application in abrasive and in such a way that titanium weight portion in the compo‐ finishing materials, in nozzles of sand‐blasting and gas‐ site made 1; 3 and 5 % (which was equivalent to 1.45; jet facilities. Boron carbide preserves hardness at high 4.35 and 7.25 wt.% of titanium diboride). Fine‐grained temperatures, which ensures its using as indentor at graphite, type APB was used for mould making, the inner 0 temperatures up to 2000 C [2]. surface of which was covered with graphite foil “Sigraf‐ However, despite its outstanding features, consi‐ lex”. Powders were pressed by method of hot pressing in dered above, boron carbide, due to its fragility cannot be vacuum in 2150 – 2200 0C temperature range and at 20‐ used as a constructive material. This is explained by the 25 MPa pressure. Pressing duration was 5 – 8 min. structure of its crystal lattice (rhombohedral, comprising Cylinder items of all four mixtures with dimensions three B4C molecules, or hexagonal, comprising nine B4C Φ70X5.7 mm were pressed to determine individual qual‐ molecules [3‐4]) (Fig. 1), by hardness and direction of co‐ ities of the obtained material. From the above cylinders valent bonds in the crystal lattice [1‐2]. Besides, low im‐ the samples of various dimensions were cut for further pact elasticity boron carbide shows low mechanical measurements of the obtained materials: 5X10X15 mm bending strength. samples were cut to measure water absorption, open One of the ways to increase impact elasticity is to dope porosity, impact elasticity and compressive resistance. boron carbide with metal elements, which provides growth 5X5X50 mm samples were cut to measure thermal ex‐ of free electron fraction in boron carbide [1]. In this work pansion coefficient, while 5X5X45 mm samples – for impact elasticity increase was achieved by titanium diboride bending strength determination. Samples sides were introduction as a doping material into B‐C system. processed with fine grain diamond grinding wheel.

Table 1 Boron carbide powder specifications Boron carbide Grade HP B:C Ratio 4.0 Boron content, wt.% 77.1 C, wt.% 21.7 N, wt.% 0.1 O, wt.% 0.9 Fe, wt.% 0.04 Si, wt.% 0.11 Al, wt.% 0.02

Other 0.3 Specific Surface, m2/gg 10 a) Green Density, g/cm3 1.5 PSD 90%, μm 6.2 PSD 50%, μm 2.9 PSD 10%, μm 0.9

Density of the samples made 92 – 96 % of theoretical value. X‐ray‐structural analyses was made using DRON‐3 Diffractometer. Diffraction pattern clearly shows boron carbide and titanium diboride sharply drawn peaks, as well as SiO2 impurities, which presumably were intro‐ duced during samples crushing in agate mortar. Fig.2 presents diffraction patterns of boron carbide and tita‐ nium diboride, while Fig. 3 – diffraction pattern of boron b) carbide doped with titanium.

c) a) Fig.3. Diffraction patterns of boron carbide doped with titanium diboride: a) 1 % Ti; b) 3 % Ti; c) 5 % Ti.

The samples were studied under electron micro‐ scope. Fig.4 shows electron microscope patterns of bo‐ ron carbide containing 1 and 3 wt% titanium, while Fig.5 shows boron carbide containing 5 wt% titanium. It is obvious from the figures that the material con‐ sists only of two phases: boron carbide (basic phase) and titanium diboride. The latter is located as small inclu‐ sions both at the boundaries and inside boron carbide b) grains. The patterns clearly show distinct phase bounda‐ Fig.2. Diffraction patterns of boron carbide (a) ries and pores decrease is observed around titanium di‐ and titanium diboride (b) boride grains.

.a) b) Fig.4 –Electron microscope patterns; 2000‐fold magnification: a) B‐C‐Ti, Ti – 1 wt.%; b) B‐C‐Ti, Ti – 3 wt.%

.a) b)

Fig.5. Electron microscope patterns of B‐C‐Ti, Ti – 5 wt %; a), b) – X2000‐fold magnification; c) – X5000‐fold magnification.

Besides, the samples were tested for bending pact elasticity were tested. The obtained results are pre‐ strength and compressive resistance, their thermal ex‐ sented in Table 2. pansion coefficients were determined, hardness and im‐

Table 2 Results of samples testing

Specification B4C B-C-T, 1%Ti B-C-T, 3%Ti B-C-T, 5%Ti

0.25 0.85 0.75 0.54 Water absorption, % 1.40 1.25 1.05 1.55 4.02 2.04 2.08 2.02 0.85 3.62 2.54 2.35 Open porosity, % 3.45 4.25 3.32 2.68 9.52 5.03 5.05 3.85 2.46 2.50 2.56 2.59 Density, g/cm3 2.43 2.49 2.54 2.58 2.34 2.47 2.51 2.55 Thermal expansion coeffi- 4.898 3.75 4.53 4.55 cient, 1/grad.10-6 (800°C) 186 206 275 343 Bending strength, MPa 196 253 290 355 210 285 305 365 305 367 415 898 Compressive strength, MPa 269 540 797 1061 346 88;91 Hardness, HRA - 97 98 85;86;94 2.9 Impact elasticity, kJ/m2 6.67 7.1 7.56 3.2

The obtained data show that boron carbide doping with titanium resulted in improved mechanical parame‐ References ters of boron carbide, which is especially important as 1. Refractory borides and cilicides. Kiev, “Naukova concerns substantial growth of compressive resistance dumka”, 1977. and impact elasticity. Increase in impact elasticity sub‐ 2. V.V.Jemelinski, M.S.Kovalchenko, G.N.Makarenko. stantially raises the importance of the work. The above Indentor materials for measuring of hardness at phenomenon is supposed to increase the fraction of free high temperatures. Powder mettalurgy. No 2(122), electrons [1‐5], which is confirmed by metal solution; the 1973. latter process provides elasticity increase preserving co‐ 3. K.Silver. Processing of nano‐sized boron carbide valent‐type bonds. Only is this case high hardness can be powder. Thesis presented to the Academic Faculty. preserved, which is clearly seen in the above Table. 2007. 4. F.Mauri, N.Vast, Ch.J. Pickard. Atomic structure of 3. CONCLUSION icosahedral B4C boron carbide from first principles

Composite B4C ‐ TiB2 with improved parameters was analysis of NMR spectra. Physical review letters, obtained. The above composite can be applied in mea‐ v.87, No 8, 20 August 2001 surements of refractory material hardness at tempera‐ 5. Yu.B. Paderno, A.B. Lyashchenko, V.N. Paderno, tures up to 2000 0C. Besides, possibility of its application V.B. Filipov, A.N. Martinenko. Composite materials V‐VI in nuclear engineering, in abrasive materials, etc. also ex‐ on the basis of eutectics of В4С‐Ме B2 system. III tends. International Conference, Conf.works, 13‐17 Sep‐ Simultaneous increase of strength and hardness pa‐ tember, 2004, Kiev. rameters provides important possibility to use this ma‐ terial as construction ceramics.

uak 669:621:762 boris karbidis meqanikuri Tvisebebis gaumjobeseba B‐C‐Ti sistemaSi z. mestviriSvili*, i. hainrixi**, z. kovziriZe* *qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, 0175, Tbilisi, kostavas 69, saqarTvelo; **klaustalis teqnikuri universiteti, arametaluri masalebis instituti, klaustal-cellerfeldi, centnerStrase 2a, germania.

reziume: ganxilulia eqsperimentuli samuSaoebi, romlis mizania boris karbidis meqanikuri Tvisebebis gaumjobeseba sistemaSi malegirebeli elementis SeyvaniT. malegirebel elementad gamoyenebulia titani, romelic sistemaSi Seyvanilia TiB2-is saxiT. aRebuli iyo oTxi Sedgenilobis kazmi. dadginda optimaluri teqnologiuri parametrebi da malegirebeli elementis Semcveloba maRali meqanikuri Tvisebebis mqone kompozitis misaRebad.

sakvanZo sityvebi: boris karbidi; titanis diboridi; sisale; simyife; dartymiTi sib- lante; cxlad wnexva; kompoziti; legireba.

UDC 666.76 HIGH REFRACTORY COMPOSITES ON THE BASIS OF SILICON CARBIDE A. Eliozashvili, N. Nizharadze, V. Kinqladze, Z. Kovziridze Department of Chemical and Biological technologies, Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] temperature and pressure, i.e. when using hot pressure Resume: High refractory composite on the basis of method. Simultaneous action of temperature and pres‐ silicon carbide base with complex binder is received with sure accelerates the process of material transportation burning of SiC‐Si and clay mixture in nitrogen medium at in liquid and solid phases contact zone[5‐6]. temperature 14200C. The composition of silicon carbide The regulation of liquid phase amount, of the tem‐ binder is stated the main component of which is silicon perature of its origination in case of silicon carbide sin‐ tering is achieved with introduction of special additives, oxynitride – Si2ON3. From the mentioned composite material (SiCl) and of oxide additives, as a rule. with addition of 30% aluminum oxide nanopowder (SiC2) These sintering activating additives participate in the samples are hot pressure moulded in vacuum at phase shaping and microstructure formation. In such a 16000C with pressure 16 MPa and with 5‐7 minutes delay way they help and have important effect on service at the last temperature. properties of the sintered material. Some physical‐mechanical properties of samples re‐ ceived with initial and hot pressure are investigated. The 2. THE BODY OF THE ARTICLE mechanical factors of the samples obtained with hot Using silicon carbide matrix the composite is received pressure are: ultimate compression strength ‐ 1465 MPa, with reactive sintering method when burning silicon car‐ bide, silicon and refractory clay mixture in (technical) ni‐ HRA – 92, for samples obtained with addition of Al2O3 0 are 1598 MPa, HRA – 93, respectively. trogen medium unpurified from oxygen [7] at 1420 C Microstructure and phase composition of the re‐ temperature. ceived composites are studied with X‐ray structural, ras‐ We studied phase composition, microstructure and ter electron‐microscopic and optical analysis. some physical‐technical properties of the mentioned composite and samples received with hot pressure me‐ thod of the same composite. The results are presented in Key words: silicon carbide; microstructure; X‐ray this work. structural analysis; hot pressure. From the mixture of silicon carbide, silicon and Cha‐ sov‐Yar ore refractory clay, the material composition of 1. INTRODUCTION which is presented in Table 1, we prepared sample‐ Silicon carbide and materials on its basis are distin‐ cylinders with sizes d‐15 mm, h‐15mm, moulded them guished with high mechanical indices at high tempera‐ under 200 MPa pressure with semi‐dry method. After ture, resistance to aggressive media, wear resistance, drying the samples were burned in furnace at tempera‐ etc. Therefore, the researches are in progress as the pos‐ ture 14200C in nitrogen medium with 2 hours delay at sibilities of material science in silicon carbide sphere are the last temperature. The rate of temperature rise was not yet exhausted [1‐4]. 2500C/h. The properties of the received samples were For realization of potential possibilities of this com‐ studied and the physical‐mechanical indices are given in pound the creation of high density materials and items Table 1. technology is necessary, which ensures their use in con‐ The received samples were broken, grounded and structive purposes. The particular problems arise at rea‐ two powders were prepared for receiving samples with lization of sintering process which is hampered because hot pressure method (Table 2). As is seen from the Ta‐ of strong covalent bonds and low mobility of atoms in sil‐ ble, SIC1 is powder sample received with reactive sinter‐ icon carbide crystalline lattice. ing method, SIC2 is material received with addition to In sintering process material transportation is par‐ the previous sample of 30% Al O nanopowder. As was ticularly activated when using such method of solidifica‐ 2 3 mentioned above, the receiving of solid material on the tion when material is simultaneously affected with high basis of silicon carbide powder requires the selection

and introduction of such additives which support sinter‐ duction of Al2O3 nanopowder into SiC 1 composition also ing process as a result of liquid phase creation. improves all indices. In our composition in order to receive samples with Ultimate compression strength for SiC1 is equal to hot pressure method and for improvement of material 1465 MPa while for SK samples received with reactive sintering process, magnesium oxide and rare earth ele‐ sintering the same index is 120 MPa. Open porosity in ment ‐ yttrium oxide Y2O3 ‐ were used as additives. High the first case is 2.9%, in the second one – 16.8 %. The in‐ melting temperature of these oxides ensures formation troduction of Al2O3 nanopowder into SiC1 composition of high temperature eutectic melt in mixture which will improves all indices. Ultimate compression strength is promote the process of material sintering. This has an 1599.8 MPa, open porosity ‐ 1.2%, hardness ‐ 93 HRA, essential importance for receiving items of high thermal thermal resistance is > 50 thermal exchange. resistance and strength. Compared to SiC values phase composition of sam‐

MgO and Y2O3 were added to powder above 100% in ples before and after pressurization was determined amounts 1 and 1.5%, respectively. with X‐ray structural analysis with of diffractometer Hot pressure temperature was 16000C. Pressurization DPOH‐3. Structural research was done by means of mi‐ pressure was 16 MPa. Delay of 5‐7 minutes at the last croscope. temperature. Heating was performed in vacuum. For in‐ According to microscopic analysis the basic part of vestigation of samples received with reactive sintering SIC1 consists of distinctly differing coarse and medium size and hot pressure method the comparative tests had silicon carbide grains. The interval between grains is filled been carried out for all compositions for determination with binder (Fig.1 a,b) which represents glassy phase re‐ of the following property indices: compressive strength, ceived as a result of clay burning which contains quite open porosity, thermal resistance, density and hardness. great amount of silicon oxinitride (Si2ON2). It represents If we compare property values which are chosen as the main component of binder. Small amount of mullite indices and are given in Tables 1 and 2, we can notice crystals are noticed there which are also formed at clay moulding method effect on physical‐mechanical indices. heating at high temperature. This figure is more clear at Compressive strength and open porosity (Tabl. 2) of microscopy expansion, particularly: at X200 and 500 ex‐ samples received with hot pressure changed abruptly for pansion (Fig.1 c,d). The Figures show that silicon carbide SIC 1 samples compared to the respective indices of SK grains are isolated from each other and intervals between samples received with reactive sintering method. Intro‐ them are filled with well sintered binder. Table 1 Material composition of charge and properties of the received samples Components, mass.% Physical‐mechanical indices Ultimate Thermal Pressure Open Index Density, compression stability, Refractori‐ SiC Si Clay of moul‐ porosity, g/cm3 strength, Heat ex‐ ness, oC ding, MPa w% MPa change SK 75 13.5 11.5 20 16.8 2.88 120 25 1770

Table 2 Properties of samples received with hot pressure Components, mass% Physical‐mechanical properties ‐

3 ‐ ‐

Burning tem

Moulding min.

MPa

tempe‐

com 3 resis last

3 g/cm

Index pressure, sion O O ‐ 2 at %

2 rature, SK

porosity,

exchange HRA Y MgO

Al MPa

0 tance,

T C pres Hardness, perature Delay Thermal Ultimate Density, Heat Open strength, SiC1 100 ‐ 1 1.5 1600 16 5‐7 2.9 1465.0 92 3.08 40 SiC2 70 30 1 1.5 1600 16 5‐7 1.2 1599.8 93 3.19 50

a) b)

c) d) Fig.1. SiC1 refractory microstructure at different expansion: a) x50 b) x100; c) x200; d) x500

a) b)

c) d) Fig.2. SiC2 refractory microstructure at different expansions: a) x50; b) x100; c) x200; d) x500

Compared to SiC1, structure of SiC2 is different dhkl 4.70; 4.47; 3.38; 2.745; 2.43; 2.395; 1.088; 1.79;

(Fig.2). The main component here is again silicon carbide 1.774Ǻ; silicon Si ‐ dhkl 3.145; 1.919Ǻ; SiO2 ‐ dhkl 4.06Ǻ sil‐ but it is not coarse grain. Grains are medium and fine icon nitride, Si3N4 ‐ dhkl 2.745; 2.581Ǻ. crystalline. In this sample there are well crystallized co‐ In roentgenogram of SiC1 sample received with hot rundum grains which are quite fine crystalline. It differs pressure there is silicon carbide peak of the same inten‐ from SiC1 in that in this sample there is a great amount sity and silicon oxinitride lines of the same intensity as in of mullite crystals which are generated as a result of in‐ the initial sample. There if no silicon here and silicon ni‐ ternal molecular transformations of clay and with inte‐ tride was fixed in small intensity – Si3N4 ‐ dhkl 2.575Ǻ. raction of Al2O3 added to charge with clay component Mullite was detected neither in the initial sample nor in

SiO2. The distinct difference between these two samples the samples received with hot pressure. is also that SiC1 structure (Fig.1) is inhomogeneous while In roentgenogram of Al2O3 containing SiC2 the silicon

SiC2 (Fig.2) is homogeneous the binding mass of which carbide peaks are of the same intensity, Al2O3 ‐ dhkl contains compactly packed crystals. Non of the samples 3.476; 2.385; 2.08; 1.600Ǻ, so are diffraction maximums contains pores. The X‐ray structural analysis of these characterized to Si2ON2 ‐ dhkl 4.64; 4.44; 3.38; 2.80Ǻ, sili‐ samples coincides with microscopic research data. con nitride dhkl 2.666; 1.740Ǻ. Silicon is not present here

Fig.3 presents diffractogram of the initial sample and either. Different from SiC1 samples here is mullite dhkl in Fig 4 ‐ diffractogram of SiC1 and SiC 2. 5.37; 3.616; 3.38Ǻ. The comparatively low intensity

In roentgenogram of the initial sample (Fig.3) the fol‐ peaks of Al2O3 is explained with the fact that here its part lowing phases are fixed: silicon carbide – SiC ‐ dhkl 2.627; is spent for creation of mullite.

2,52; 2,39; 2,36; 2.176; 2.000Ǻ; silicon oxinitride Si2ON2 ‐

Fig. 3. Diffractomogram of the initial sample

Fig. 4. SiC1 and SiC2 diffractomograms

3. CONCLUSION Introduction of Al2O3 nanopowder into SiC1 composi‐ On further treatment of samples received with reac‐ tion gives SiC2 composite with differing microstructure tive sintering on the basis of SC and on their moulding and creation of complex binder in the phase. with hot pressure method abrupt growing of the physi‐ SiC2 composite has homogeneous, fine crystalline cal‐mechanical indices occur. structure and higher physical‐mechanical indices com‐ With hot pressure on the basis of SiC a composite pared to SiC1. with complex binder is received which contains the same High exploitation indices of the received composites components that were formed at reactive sintering. cause silicon carbide items using in constructive mate‐ rials.

References 4. R. Ruh, L.B. Bentsen, D.P. Hasselman. J. Amer. Ceram. 1. M.A. Janney. Amer. Ceram. Soc. Bull., 1987, v.66, No 2. Soc. 1984, v.67. No 5, p. C‐83‐C‐84. p.322‐324. 5. R.A. Cutler, A.W. Vilkar, J.B.Holt. Ceram. Eng. Sci. Proc. 2. G.C. Wei, P.F. Becher. J. Amer. Ceram. Soc. 1984. v.67, 1985. v.6. No 7/8. p.15‐21. No 8, p.571‐574. 6. K. Niihara, A. Nikahira, T. Uchigava. Fract. Mech. Ce‐ 3. R. Ruh, A. Zangvil, J. Barlow. Amer. Ceram. Soc. Bull. ram. v.7. – Plenum Press, 1986. p.103‐116. 1985. v. 64, No 10. p.1368‐1373. 7. Z. Kovziridze, N. Nizharadze, G. Donadze, V. Kinkladze. SiC with complex binder. Ceramics, 2(16), 2006, p.12.

uak 666.76 maRalcecxlgamZle kompozitebi siliciumis karbidis bazaze a. eliozaSvili, n. niJaraZe, v. qinqlaZe, z. kovziriZe saqarTvelos teqnikuri universiteti, qimiuri da biologiuri teqnologiebis departamenti, Tbilisi, 0175, kostavas 69, saqarTvelo.

reziume: SiC-Si da Tixis narevis azotis garemoSi gamowviT 14200C temperaturaze miRebulia maRalcecxlgamZle kompoziti siliciumis karbidis bazaze kompleqsuri SemkvreliT. dadgenilia siliciumis karbidis Semkvrelis Sedgeniloba, romlis ZiriTadi komponentia siliciumis oqsinitridi _ Si2ON2 . aRniSnuli kompoziciuri masalisagan (SiC1) da masze 30% aluminis oqsidis nanofxvnilis damatebiT (SiC2) dayalibebulia nimuSebi cxeli dawnexiT vakuumSi 16000C-ze, 16 mpa wneviTa da bolo temperaturaze 5_7 wuTi dayovnebiT. Catarebulia Tavdapirveli da cxeli dawnexiT miRebuli nimuSebis zogierTi fizikur-meqanikuri Tvisebis kvleva. cxeli dawnexiT miRebuli nimuSebis meqanikuri maCveneblebi Seadgens: simtkicis zRvari kumSvisas 1465 mpa, HRA – 92, AI2O3-is damatebiT miRebuli nimuSebis, Sesabamisad – 1598 mpa, HRA - 93. rentgenostruqturuli, rastruli eleqtronul-mikroskopuli da optikuri analiziT Seswavlilia miRebuli kompozitebis mikrostruqtura da fazuri Sedgeniloba.

sakvanZo sityvebi: siliciumis karbidi; mikrostruqtura; rentgenostruqturuli analizi; cxeli dawnexa.

UDC 669:621:762

STRUCTURAL RESEARCH OF AL2O3‐TiC SYSTEM NANOCERAMIC COMPOSITE MATERIAL N. Kiknadze*, J. Hainrich**, R. Goerke**, G. Tabatadze*, Z. Kovziridze* * Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia; **Technical University of Claustal, Institute of Non‐metallic Materials, Claustal – Zellerfeld, 38678, Zehntnerstrasse 2a, Germany.

E‐mail: [email protected] perspective material in the development of metal work‐ Resume: The results of structural research of the ing industry. In the work [5] authors have presented composite samples received with hot pressure of Al2O3 ‐TiC system composite materials are presented. As a result of re‐ material with different additions into aluminum oxide searches it is stated that at hot pressure between up to and titanium carbide system. The received material was 15500C, titanium carbide and aluminum oxide do not in‐ characterized, on the one hand, with high hardness 92‐ teract with creation of some new phase. In case of hot 93.5 HRA and wear resistance, and on the other hand, pressure sintering, small additions of titanium carbide with high bending strength – 680 MPa. and oxides (MgO, Y2O3) prevent the growth of aluminum oxide grains, ensure material compactness and mechani‐ 2. THE BODY OF THE ARTICLE cal strength while as to the effect of carbon fiber it has, The purpose of research of the presented work was in our opinion, double meaning: it heightens composite the investigation of additives effect on Al2O3‐TiC system bending strength and at the same time helps to preserve composites (MgO; Y2O3 and C‐fiber) on the creation of titanium carbide stoichiometric composition. the structure of samples received with hot pressure. The samples were prepared according to technologi‐ cal scheme described in [5]. In composition of the first Key words: composite materials; cutting tool ma‐ group composites only titanium carbide content* was terial; aluminum oxide; titanium carbide; additives; C‐ changed, while to the content of the second group com‐ fiber; microstructure. posites the combination of 2 types of activators in

amount of 5 mass% was added: 1. MgO‐25; Y2O3‐75; 2. 1. INTRODUCTION MgO‐11.1; Y2O3‐33.4; C‐fiber‐55.5 mass% content. In spite that on the basis of aluminum oxide various Sintered samples were used to prepare sections with cutting tool materials are created [1‐4], it all the same traditional method [6]. Some physical‐mechanical indices has not yet exhausted its possibilities. Therefore, be‐ of samples are presented in Table 1. cause of its unique properties it is considered as quite

Table 1

Mechanical properties of samples of Al2O3‐TiC system composites received with hot pressure

Titanium carbide Temperature of sintering, 0C and additives con‐ 1500 1550

tent in Al2O3 ‐TiC Relative Hardness σcomp σbend Relative Hardness σcomp σbend composite, mass% density HRA MPa MPa density HRA MPa MPa TiC 10 0,84 92 1000 420 0.98 93 1900 480 TiC 20 0,90 92,5 1080 460 0.98 93.5 2500 550 TiC 40 0,92 93 1100 500 0.98 94 2700 550 TiC 20 add. 1 0.96 93 1700 520 0.99 93 2500 630 TiC 10 add. 2 0.90 92 1500 450 0.99 92.5 2250 580 TiC 20 add. 2 0.93 92.5 1850 560 0.99 93 3000 680 TiC 40 add. 2 0.96 93 2000 520 0.99 93.5 2700 650

Microscopic research of microsections was done at composites the opinion presented in [6,7] is proved that the University of Claustal, Germany, on Cam Scan micro‐ at hot pressure up to 15500C between aluminum oxide scope, micro hardness was measured on CD Muecke‐ and titanium carbide there happens no interaction creat‐ Haerte device at the department of ceramic materials ing some new phase. The microstructure of researched and items of Bremen University. composites consists of two phases (Al2O3 and TiC). With consideration of X‐ray phase analysis (Fig. 1) and microscopic pictures (Fig.2,3) of Al2O3‐TiC system

0 Fig.1. X‐ray patterns: a) TiC; b) Al2O3; c) TiC 20%‐Al2O3 80% received at 1550 C with hot pressure

The same is proved with parameter value of titanium aluminum oxide matrix, the jointing of their grains are carbide crystalline lattice TiC (422)‐4.318Ǻ and micro not noted. The form of titanium carbide grains nears to hardness index of titanium carbide 25 GPa which abso‐ spherical, their average diameter Dav is 3 mcm (Fig.3) and lutely conforms to the indices presented in [6]. is almost not depended on titanium carbide amount. Po‐ As the microscopy pictures of first group samples rosity is as more as less is titanium carbide content in show titanium carbide is homogeneously redistributed in sample.

.a) b) c)

Fig.2. Microscopic pictures, X250; a) TiC 40%‐ Al2O3 60%; b) TiC 20%‐ Al2O3 80%; 0 c) TiC 10%‐ Al2O3 90%. Sintering temperature – 1550 C

.a) b)

0 Fig.3. Electronic‐microscopy pictures, x 4000. a) TiC 40%‐ Al2O3 60%; b) TiC 10%‐ Al2O3 90%. Sintering temperature is 1550 C.

The hardness of each composite of the first group grains does not occur but microstructure intergrain (Table 1) absolutely satisfies the demands put to cutting spaces are not completely filled which affects negatively material [8] but it is desirable that ultimate hardness be on mechanical properties of these composites. higher. In this case, intensive growth of aluminum oxide

.a) b) c)

Fig.4. Microscopic pictures, X 250; a) TiC 40%‐ Al2O3 60%; b) Tic 20%‐ Al2O3 80%; 0 c) TiC 10% ‐ Al2O3 90% (in addition 1). Sintering temperature is 1550 C.

The form and distribution character of carbide grains do not change under the effect of additives add‐ ed to composites while porosity substantially decreases (Fig.3). At the same time the additives together with ti‐ tanium carbide prevent intensive growth of aluminum oxide grains (Fig.5) which is very intensive at sintering of pure aluminum oxide. The fact of grain size retaining is most clearly noticed in 10% titanium carbide contain‐ ing composite where the amount of titanium carbide grains is less and aluminum oxide matrix is seen more clearly. Aluminum oxide grains are quite well sintered to each other although some intergrain pores are no‐ ticed. Fig.5. TiC 10%‐ Al O 90% (in addition 1) composite 2 3 microstructure. Sintering temperature 15500C. X 4000

Microstructure dispersion and material compactness Composites with and without additives almost do not degree is reflected on the indices of physical‐mechanical differ from each other in micro hardness indices, only properties of these samples (Table 1), mechanical careful studying of indentations revealed that cracks at strength of samples with additives comparatively ex‐ the tops of indentations in case of composites with addi‐ ceeds strength indices of composites without additives. tives are not fixed compared to some composites re‐ ceived without additives (Fig.6‐7).

.a) b)

Fig.6. HV data of TiC 20% ‐ Al2O3 80% composite .a) Time dependence of indentor load on the sample and distance; b) indentor imprint, x500

.a) b)

Fig. 7. HV data of TiC 20% ‐ Al2O3 80% composite (with additives 1) .a) Time dependence of indentor load on the sample and distance; b) indentor imprint, x500

As to the effect of carbon fiber, we think it has or torn out from the surface which may be negatively af‐ double load: it increases composite bending strength fected on cutting material properties [8]. Carbon fiber in (Table 1) and at the same time helps to preserve tita‐ material is located undirected (Fig.8). The damaged nium carbide stoichiometric composition. But it should boundaries of carbon fiber as a result of section prepara‐ be noted that if carbon fiber particle occurs on cutting tion are seen on the picture. tool edge, in the process of cutting it may be burnt out

Fig.8. Microscopic pictures, X400; TiC 20% ‐ Al2O3 80% (with additives 2)

From composites of TiC 20%‐ Al2O3 80% (with addi‐ 3. B.Ya.Brach, P.A.Sitnikov, Yu.I.Ryabkov. Oxide‐ tives 2) composition (Table 1) cutting plates with sizes carbide composite material on the basis of corun‐ 12x12x5 mm were prepared and tested for wear resis‐ dum ceramic matrix. Prospective investigations in tance in cutting process. Steel 40 was taken as peo‐ the sphere of new nonmetallic materials. Works of cessed material. Cutting rate was 300 m/min, supply ‐ S‐ Komi scientific center of UrO of Russian AS, 1999, 0.3 mm/rot., cutting depth ‐ t=0.5 mm. Before wearing No 161, p.85‐93. to 0.6 mm the test plate worked for 400 hours. 4. I.Lewis, D.Schwarenbach, H.D.Flack. Electric field gra‐

dients and charge density in corundum, α‐ Al2O3, Acta 3. CONCLUSION Cryst. A38 (1982), p.733‐739. The results of the research of structural and physical‐ 5. Z.Kovziridze, G.Tabatadze, G.Grathwohl, Cutting na‐ nd mechanical properties of Al2O3–TiC system composite noceramics in the Al2O3–TiC system. 2 International materials received with hot pressure are presented. An Congress on Ceramics. June 29‐July 4, 2008. Verona, opinion is expressed that the set of MgO, Y2O3 and car‐ Italy. bon fiber additives, use of aluminum oxide nanopowder 6. Yu.I.Krilov, E.A.Ballakir. Carbide‐oxide systems. Ref‐ and hot pressure makes desired conditions that at re‐ erence book, Moscow, “Metallurgia”, 1976, p.231.. ceiving of Al2O3–TiC system composite materials there 7. Z.Kovziridze, G.Tabatadze, G.Grathwohl, G.Luecke. happens no intensive growth of corundum grains. At the Nanoceramic composite in the Al2O3–TiC system. same time practically poreless material with high me‐ “Ceramics” Journal of ceramists’Association of Geor‐ chanical and cutting properties is received. gia, No 1(18), Tbilisi, 2008, p.3‐6. 8. T.Loladze. Strength and wear resistance of cutting References tools. Moscow, “Machinostroenie” 1982, p.320. 1. Ceramic tool materials. Ed. by Dr of Technical sciences G.G.Gnesina, Kiev, “Tekhnika”, 1991, 390 p.. Acknowledgement 2. Khamano Kenia, Khara Takeshi, Khwuang Chi‐Shiang We thank Prof. G.Grathwohl and the whole person‐ et al. Some properties and sintering ability of highly nel of the department of ceramic materials and items of pure finedispersed alumina powders. Ege kekaisi, the University of Bremen for assistance. 1986, v.94, No 3, p.372‐379.

uak 669:621:762 Al2O3 – TiC sistemis nanokeramikuli kompoziciuri masalis struqturuli kvleva n. kiknaZe*, i. hainrixi**, r. goerke**, Gg. tabataZe*, z. kovziriZe* *saqarTvelos teqnikuri universiteti, qimiuri da biologiuri teqnologiebis departamenti, Tbilisi, 0175, kostavas 69, saqarTvelo; **klaustasis teqnikuri universiteti, arametaluri masalebis instituti, klaustal- cellerfeldi, centnerStrase 2a, germania.

reziume: warmodgenilia Al2O3—TiC sistemis kompoziciuri masalis cxeli wnexiT miRe- buli nimuSebis struqturuli kvlevis Sedegebi. kvlevis Sedegad dadasturebulia, rom 15500C-mde cxeli wnexis dros titanis karbidi da aluminis oqsidi ar urTierTqmedebs raime axali fazis warmoqmniT.

cxeli wnexiT Secxobis pirobebSi titanis karbidi da oqsidebis (MgO, Y203) mcire danamatebi xels uSlis aluminis oqsidis marcvlebis zrdas, uzrunvelyofs masalis kompaq- turobas da meqanikur simtkices, rac Seexeba naxSirbadis boWkos gavlenas, Cveni azriT, mas ormagi datvirTva aqvs: igi TavisTavad amaRlebs kompozitis simtkices Runvisas da xels uwyobs titanis karbidis steqiometriuli Sedgenilobis SenarCunebas.

sakvanZo sityvebi: kompoziciuri masala; mWreli sainstrumento masala; aluminis oqsidi; titanis karbidi; danamatebi; C-boWko; mikrostruqtura.

UDC 658.373 ENERGY MANAGEMENT ISSUES M.Gudiasvili*, T. Jishkariani** *Faculty of Power Engineering and Telecommunication, Department of Electric Power Engineering, Electronics and Electromechanic Engineering; **Faculty of Power Engineering and Telecommunication, Department of Thermal and Hydro‐Power Engineering. Georgian Technical University, 77, Kostava St. Tbilisi 0175, Georgia.

E‐mail: [email protected]; [email protected] both reduced energy consumption and reduced emissions Resume: XXI century is characterized by a growing of environmental pollutants. global demand for energy. Energy consumption of build- Industrial audits are some of the most complex and ings is between 35-40% that leads to growing emissions most interesting audits because variety of equipment found in these facilities. Many of the industrial equipment can be of CO2. The use of environmentally-sensitive design strat- egies, the improvement of building envelope, the change found during commercial audits. Too large chillers, boi- of energy consumption patterns in people through infor- lers, ventilating fans, water heaters, coolers and freezers, mation and awareness, the combination of sustainable and extensive lighting systems often are the same in most technologies, use of renewable energy are the main al- industrial operations as those found in large office build- ternative ways to improve energy efficiency and reduce ings or shopping centers. The challenge for the auditor and gas emissions. energy management specialist is to learn how this complex The general trend of research and development of and often unique industrial equipment operates and to energy efficiency in industrial, commercial and residen- come up with improvements to the processes and the tial buildings is energy auditing process. To follow the equipment that can save energy and money. design guidelines and use bioclimatic design, passive so- Commercial audits generally involve substantial con- lar heating, natural cooling and day lighting, insulated sideration of the structural envelope features of the facili- high-resistance envelope, thermal storage, double glazing ty, as well as significant amounts of large or specialized and perform the energy auditing in industrial, commercial equipment at the facility. Office buildings, shopping cen- and residential areas would be reached low-energy con- ters all have complex building envelopes that should be sumption and create a comfortable indoor environment examined and evaluated. Building materials, insulation levels, door and window construction, skylights and with a minimum thermal zoning between areas [2]. many other envelope features must be considered in order

to identify candidate ‘Specific Changes’. energy efficiency, auditing, CO emis- Key words: 2 The residential auditor should start by obtaining pre- sions, renewable energy. vious energy bills and analyzing them to determine any patterns or anomalies. During the audit visit the structure 1. INTRODUCTION is examined to determine the levels of insulation, the Energy audit is one of the first tasks to be performed conditions of end seals for windows and doors and the infor accomplishment of an effective energy cost control tegrity of the ducts. The space heater or air conditioner is program. Energy audit consists of a detailed examination inspected along with the water heater. Equipment model of how a facility uses energy, what the facility pays for that numbers, age, size, and efficiencies are recorded. energy and finally, a recommended program for changes in Energy auditing examples are given here in order to operating practices or energy consuming equipment that illustrate energy savings[1]. will cost effectively save money on energy bills. Saving money on energy bills is attractive for busi- 2. THE BODY OF THE ARTICLE nesses, industries and individuals alike. Customers, Manufacturing company auditing: A ventilating fan whose energy bills use up a large part of their income and at a fiberglass boat manufacturing company has a stan- especially those customers whose energy bills represent a dard efficiency 12 hp motor that runs 2000 hours per year substantial fraction of their companies operating costs, (1 horsepower is 746 watt=0,746 kW). have a strong motivation to initiate continuation of an When this motor wears out, the company will use a on-going energy cost control program. In many cases high efficiency motor. A high efficiency 12 hp motor these energy cost control programs will also result in costs around 200 Gel more than the standard efficiency

model. The standard motor is 70% efficient and the high Companies generally have a corporate standard for the efficiency model is 90% efficient. The cost savings is discount rate used in determining their measures used to found by calculating: make investment decisions. For a 10 year assumed life [12hp*2000hr/year *0,746 kW/hp]*[(1/0,70)- and a 10% discount rate, the present worth factor is found (1/0,90)] * (0,08 Gel/kWh)=455 Gel/year; as 6, 144 [3]. The benefit-cost ratio is found as Payback period is: 200Gel/455=0,44 years or about 6 B/C= 455 Gel* 6,144/200Gel=13,9 this is quite attrac- months. tive benefit/cost ratio[4]. The discounted benefit-cost ratio can be found once a motor life is determined and a discount rate is selected.

Table 1

# Indicators Standard motor High efficiency motor

1 Efficiency, % 70 90 2 Operation hours 2000 2000 3 Power 12hp*0,746=8,95 12hp*0,746 kW/hp =8,95 kW kW 4 Electricity price 0,08 Gel/kWh 0,08 Gel/kWh 5 Power savings 12hp*2000hr/year *0,746 kW/hp]* [(1/0,70)-(1/0,90)] * (0,08 Gel/kWh)= 455 Gel/year 6 Payback period 200Gel/455=0,44 years or about ≈6 months 7 Benefit/cost [4] 455 Gel* 6,144/200Gel=13,9

Fig.1. High efficiency motors

Lighting auditing: The main step is replacing the ex‐ ings must be calculated next. The power savings is 175‐ isting 175 watt mercury vapor lamp with the 125 watt 125= 50 Watt. If the lamps operate for 3500 hours per multi vapor lamp when it burns out. The cost of the re‐ year and electric energy costs 0,08 Gel/kWh, then the placed lamp must be determined. Product catalogs can savings is: be used to get standard prices for the new lamp about (0,050 kW)*(3500hr/year* 0,08 Gel/kWh)=14 12 Gel more than for 175 watt mercury vapor lamp. The Gel/year. new lamp is direct screw‐in replacement and needs no This gives a payback period 12 Gel/14 Gel/year= 0,85 fixture or ballast. Labor cost is assumed to be the same years, or about 10 months. for installation of either lamp. The benefits or cost sav‐

Table 2

175 Watt mercury Indicators 125 Watt mercury vapor lamp vapor lamp

Price 18 Gel 30 Gel Full working period 10 000 15 000 hours Operation hours 3500h/year 3500h/year

Electricity price 0,08 Gel/kWh 0,08 Gel/kWh 175‐125=50 Watt Power savings (0,05 *3500*0,08)=14 Gel/year Payback period 12 Gel/14 Gel/year= 0,85 years≈10 months

Peak load control: A manufacturing plant has a large shot-blast cleaner that is used to remove the rust from heavy steel blocks before they are machined and welded. The cleaner shoots out a stream of small metal bills – like shotgun pellets – to clean the metal blocks. A 150 hp motor provides the primary motive force for this cleaner. This machine requires a total electrical load of about 200 Fig. 2. 175 Watt mercury vapor lamp kW which adds directly to the peak load billed by the

electric utility. At 8 Gel/kW/month, this costs: (200kW)*(8 Gel/kW/month)= 1440 Gel/month Discussions with line operating people resulted in the information that the need for metal blocks was known well in advance and that the cleaning could easily be done on the evening shift before the blocks were needed. Based on this information, the plant savings would be: 1440 Gel/month*12=17 280 Gel per year. Since there are no expenses to implement this event, the Payback period=0, that is, the payback is immediate.

Fig. 3. 125 Watt mercury vapor lamp

Table 3 # Indicators Motor 1. Power 150 hp=150 * 0,746 kW/hp=111,9 kW 2. Required electrical load 200 kW 3. Electricity load price 8 Gel/kW/month 4. Electricity load cost (200kW)*( 8 Gel/kW/month)= 1440 Gel/month 5. Plant savings 1440 Gel/month*12=17 280 Gel /year

3. CONCLUSION analyzes the changes in equipment and operations that Energy audits are an important first step in the over‐ will result in cost‐effective energy cost reduction. The all process of reducing energy costs for any building, energy auditor plays a key role in successful conduct of company or industry. A thorough audit identifies and

audit and also in implementation of audit recommenda‐ References tions. 1. E.C. Turner. Energy Management. Handbook. Pub‐ There is also a great potential for energy savings lished by Fairmont Press. 2002. P. 21‐36. and improvements in energy efficiency that needs to be 2. K. A. Hoffman. Energy Efficiency, Recovery and Sto‐ harnessed. The way is optimization, validation and rage. New York: Nova Science Publishers. 2007. P. 223‐ demonstration of new concepts and technologies for 243. buildings. The actual trend is to incorporate the combi‐ 3. R. A. Brealey, S. C. Myers. Principles of Corporate nation of sustainable technologies and dynamic strate‐ Finance. Published by McGraw‐Hill. 2000. P. 16‐34. gies for increased energy efficiency and use of renewa‐ 4. D.M. Streifford. Economic Perspective. Boston. Pub‐ ble energy [2]. lished by IRWIN, 1990. P.275‐280.

uak 658.373 energomenejmentis sakiTxebi m. gudiaSvili*, T. jiSkariani** *energetikisa da telekomunikaciis fakulteti, eleqtroenergetikis, eleqtronikisa da eleqtromeqanikis departamenti; **energetikisa da telekomunikaciis fakulteti, Tbo- da hidroenergetikis departamenti. saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 77, saqarTvelo.

reziume: XXI saukune xasiaTdeba energiis moTxovnis zrdiT. energiis moxmareba sayofacxovrebo da sxva SenobebSi 35_40%-is farglebSi meryeobs, rac ganapirobebs CO2 emisiis zrdas. Senobebis Tanamedrove daproeqtebis pirobebis dacvaze damyarebuli strategia gulisxmobs energiis moxmarebis Cvevebis cvlilebebs, rac SesaZlebelia mosaxleobis informirebulobiT da Segnebis donis amaRlebiT. mdgradi teqnologiebis da ganaxlebadi energiis wyaroebis gamoyeneba alternatiuli gzaa, romelic gamoiwvevs energoefeqturobis zrdas da gazis emisiebis Semcirebas. industriul, komerciul da sayofacxovrebo SenobebSi energoefeqturobis kvlevis ZiriTadi mimarTulebaa energoauditis procesi. bioklimaturi daproeqtebis instruqciebze dayrdnobiT da iseTi RonisZiebebis gatarebiT, rogoricaa mzis energiis, bunebrivi gagrilebis, dRis ganaTebis, maRali gamZleobis saizolacio masalebis, Termuli energiis, ormagi Seminvis da a.S. gamoyeneba, agreTve energoauditis perioduli Catareba industriul, komerciul da sayofacxovrebo SenobebSi, SeiZleba miRweul iqnes energiis moxmarebis Semcireba da Senobebis komfortuli Siga garemos Seqmna.

sakvanZo sityvebi: energoefeqturoba; auditi; CO2 emisiebi; ganaxlebadi energia.

UDC 622.7 CONSIDERATION ON THE UTILIZATION OF CHORDI BARITE‐BEARING WASTE V. Totibadze, J. Kakulia, Sh. Malashkhia, N. Lomidze, L. Kartvelishvili, N. Chubinidze, T. Guruli Caucasian Alexander Tvalchrelidze Institite of Mineral Resources, 85, Paliashvili st., Tbilisi, 0162, Georgia

E‐mail: [email protected] timal variant of restoration of barite production in the Resume: On the basis of preliminary researches re‐ country is the solving of the issue of utilization of Chordi lated to the possibility of concentration of barite‐bearing barite‐bearing waste. waste, the possibility of receiving of barite and barite‐ 2. THE BODY OF THE ARTICLE calcite flotation concentrates is established. For prepara‐ Barite‐bearing waste contains 28‐37% barite and 30‐ tion of material for flotation, the combined technological 32% calcite. If we consider high demand for calcite con‐ scheme of disintegration was developed, which ensures centrates (micronized calcite product is also imported distribution of barite and calcite particles in different size from Turkey) and the possibility of obtaining of this prod‐ classes and rising of the quality of selectivity of flotation uct together with barite concentrate, the total amount of process. these minerals in waste makes 70‐80% ‐ processing of

waste implies great cost efficiency. The wastes of Chordi Key words: Chordi barite‐bearing waste; selective Concentration Factory consist of tails of sedimentation of decrepitation of barite; flotation; barite concentrate; ba‐ 8(5)‐3(2) mm and 3(2)‐0,5mm size class and grinding and rite‐calcite concentrate. flotation of 0,5‐0,0 mm class. They are mixed together and form homogenous mass of 8‐0 mm size. The content of 1. INTRODUCTION barite and calcite according to the size of particles is dis‐ Two decades ago Georgia was the exporter of barite tributed in inversely proportional manner – barite content products. At present the share of utilization of barite increases from coarse to fine class, and calcite – from fine concentrates of local production in the industry of the to coarse (see Table #1). country is very small. Deficit is filled by barite concen‐ trates, imported from Turkey. At present the most op‐

Table 1 Spatial analysis of Chordi barite-bearing waste Barite content, Calcite content, Extraction of Extraction of Size of class, mm Output, % # % % barium, % calcite, %

1. -8,0+2,0 52,25 22,5 47,18 32,64 64,0

2. -2,0+0,4 23,79 32,8 32,55 21,56 22,8

3. -0,4+0,16 12,79 64,5 21,4 23,31 8,2

4. -0,16 11,17 70,8 16,21 22,49 5,0

Total 100,0 35,92 34,48 100,0 100,0

Content of barite in fine classes is quite high, though tions of barite and calcite is possible only by flotation. in spite of low content of barite in ‐0,8+2,0 mm size Other processes of concentration (gravitational, magnet‐ class, extraction of barite from this fraction is quite high ic, electric) are used in preparatory technological scheme due to significant output of this fraction. Finely divided of flotation of the material. Mechanical, as well as ther‐ barite particles and their ingrowths with rocks (massively mal processing processes can be used in technological with calcite, relatively seldom ‐ with quartz) are concen‐ scheme for disintegration of the material. Bringing of ini‐ trated in this fraction. Obtaining high‐quality concentra‐ tial tails to flotation size only by mechanical devices is

unprofitable, as in the process of bringing of calcite to barite of coarsely ingrained generation has the ability of flotation size barite particles might be over‐grinded to selective decrepitation, i.e. from the waste‐containing the unsuitable size for flotation. minerals only barite particles disintegrate and convert It’s well known that barite and calcite particles have into fine fraction as a result of heating. similar flotation characteristics and their division in se‐ In (‐0,16) mm fraction of sludge of wastes, output of lective concentrates is possible by complex flotation re‐ which is 9,45%, barite content reaches 70,8%, which is gime. This complexity will be removed, if we use these twice as mush as the content of this mineral in initial similar characteristics for obtaining of collective barite‐ wastes, and calcite content makes 15,45%, which is calcite concentrate by means of dispersion of quartz and twice and more as less as its content in initial tails. Ex‐ feldspars composing the wastes. The Institute of Mining traction of barite in this product makes 19,64%, and cal‐ Mechanical Engineering has developed the technological cite – 4,28%. Total content of barite and calcite exceeds scheme of obtaining of barite‐calcite concentrate from 86,0%. Chordi stored tails, which can be successfully integrated After mechanical disintegration, barite content in ‐0,16 in the barite and calcite paintwork production. One of mm fraction reduces, although the indicator of barite ex‐ the reasons of obtaining of collective concentrates is the traction in the unified flotation material rises from 13,4% proximity of flotation characteristics of barite and calcite to 55,41%. At the same time, calcite content rises and to‐ and complexity of their division, also the complexity of tal content of barite and calcite is also high – 87,07%. moving barite particles into foam product due to their Burning of the crushed material was performed after over‐grinding. Due to such problems we decided to use producing of 0,16 mm size class. In newly formed 0,16 several methods of disintegration for bringing barite and mm size class, output of which is 8,42%, barite content is calcite to flotation size. As practice has shown, the par‐ 76,0%, extraction – 79,0%, for calcite these data equal, ticles of non‐standard size intended for flotation are not to 17,3% and 4,27%, respectively and total content of effectively extracted during flotation. Barite and calcite barite and calcite makes 93,3%. concentrate in different size classes, but more accurate The output of flotation material from primary and re‐distribution of these minerals in different size frac‐ secondary sludge and newly formed class obtained as a tions is required for their preparation for flotation. result of burning of coarse fraction is 43,93%, barite con‐ For its implementation, as we have mentioned tent – 57,71% and extraction – 75,1%; and for calcite above, we consider it necessary to use the processes of 30,5% and 39,41%, respectively. mechanical crushing, as well as thermal disintegration Processing of initial sample – crushing into fine frac‐ for liberation of barite ingrowths with calcite and, in par‐ tion without preliminary sieving and burning of the ticular, with quartz. During mechanical crushing barite, crushed material without separation of ‐0,16+0 mm as relatively brittle mineral as compared with calcite and were marked by similar technological indicators (see Ta‐ quartz, concentrates in fine fraction. In the process of ble 2). thermal processing of the crushed mass, big amount of Thus, based on preparation of wastes for flotation by barite moves to newly formed fine class as a result of se‐ simplified scheme, flotation material with optimal con‐ lective decrepitation of barite. Thus, combined technolo‐ tent of barite and calcite (sum exceeds 80%) is obtained gical scheme of disintegration of tails allows distributing of for production of barite and barite‐calcite concentrate. these minerals in coarse and fine classes more effectively. The goal of the next phase is the determination of possi‐ Fine class (‐0,16 mm) with high barite content is ready for bility of obtaining of calcite concentrate as a result of flotation – obtaining of barite and barite‐calcite concen‐ grinding and flotation of coarse class. trates, and coarse classes, after grinding, can be supplied Unlike the technological scheme developed at the for flotation to obtain calcite concentrate. Institute of Mining Mechanical Engineering, which pro‐ Class ‐0,16+0 mm was considered the optimal size for vided for obtaining of only barite‐calcite concentrate, we flotation material. Primary sludge, produced from the in‐ set the goal to obtain barite and calcite concentrates as itial wastes of flotation material, was taken for the selec‐ well, which ensures the growth of complexity of utiliza‐ tion of regime of preparation of material; also secondary tion of the wastes and development of low‐waste tech‐ sludge, obtained as a result of crushing of the wastes nology. For reaching this goal, use of mechanical flota‐ and the ‐0,16+0 mm size class obtained as a result of tion equipment is envisaged after flotation preparation thermal processing. It’s well known that, in particular, of materials. Technological scheme shall provide for ba‐

rite and calcite flotation with obtaining of collective con‐ processing of sodium base of main flotation tails for cal‐ centrate, further separation of collective concentrate in‐ cite activation for obtaining of barite‐calcite concentrate to barite and barite‐calcite high‐quality concentrates, with increased content of calcite.

Table 2 Sieve-based analysis of the material, obtained as a result on burning of the crushed sample

Barite Extraction Extraction # Class size, Output, Calcite content, content, of barium, of calcite, # mm % % % % % 1. +1,0 14,58 6,6 38,9 2,81 16,33

2. -1,0+0,4 16,95 6,0 47,9 2,96 23,36

3. -0,4+0,16 24,41 26,8 40,9 19,07 31,53

4. -0,16 44,06 58,5 22,7 75,16 28,78

Total 100,0 34,29 34,03 100,0 100,0

Sodium oleate was used as collector, T=66 – as tegration of initial wastes - for determination of the pos- foaming agent, liquid glass – as depressor of waste rocks sibility of obtaining of barite and barite-calcite. Optimal (quartz, feldspars, magnesium compounds, clay), calci- regime of operation of flotation equipment was selected. nated soda – for regulation of pH of pulp. During main flotation of barite, 850 g/t sodium oleate, For obtaining of coarse concentrate of barite, flotation 400 g/t T-66 was supplied to flotation; the consumption proceeded in optimal-neutral environment for flotation, of liquid glass made 700 g/t. For obtaining of high- and for the main flotation in the process of control flota- quality barite, 500 g/t liquid glass was supplied in the tion of tails – for calcite activation – sodium alkali or cal- process of cleansing. In barite flotation tails sodium alkali cinated soda up to pH=10 meaning of pulp was supplied. was supplied in required quantity for increase of pulp pH Barite cleansing was performed against the back- up to pH=10. Technological scheme and technological ground of calcite and partially barite depression. indicators are presented in Table 3. Flotation was performed with the -0,16+0 mm sludge part produced as a result of mechanical and thermal disin-

Table 3 The results of flotation of the class of the size, produced from the product of burning (-0,16+0) mm

Barite Calcite Output, Barite content, Calcite content, Name of product extraction, extraction, # % % % % %

1. Barite concentrate 27,2 91,2 4,4 42,04 5,19

Barite-calcite 2. 19,3 67,09 23,67 21,93 22,34 concentrate 1 Barite-calcite 3. 32,8 54,8 40,1 30,46 57,09 concentrate 2

4. Tails 20,7 15.87 17,12 5,57 15,38

Total 100,0 59,01 23,04 100,0 100,0

High-quality concentrate of barite and barite-calcite is calcite concentrates, in particular, removal of ferric oxide obtained. Barite content in the concentrate makes 91,1% will raise their whiteness coefficient. and the total content of barite and calcite in barite-calcite concentrates exceeds 92,0%. References 1. J. Kakulia, Sh. Malashkhia, Determination of barite 3. CONCLUSION mining and processing directions with consideration of The obtained barite concentrate meets the require- their structural properties. Works of the International ments of the standard for KB-3 category, and the white- Scientific Conference “Newest Technologies and ness coefficient of barite-calcite concentrates exceeds Georgia”. Tbilisi, 2002. 92%. For the purpose of rising of the quality of the con- 2. M.A. Suladze. Prospects of utilization of calcite- centrates, their processing is considered by means of bearing barite ores in Georgia. “Barite”. “Nauka” M. chemical and bacterial methods. Amino acids and organic 1986. acids, produced as a result of action of silicate bacteria, 3. J. Kakulia, I. Tsintsadze, O. Mardaleishvili, V. Dum- convert iron and magnesium compositionst in soluble badze. Consideretions about mastering of Georgian technogenic deposits. Chemical Journal of Georgia, state, which will facilitate the rising of quality of barite- vol.1, #1, 2001.

uak 622.7 mosazrebani Cordis baritSemcveli narCenebis utilizaciis Sesaxeb v. ToTibaZe, S. malaSxia, n. lomiZe, l. qarTveliSvili, n. CubiniZe, T. guruli kavkasiis aleqsandre TvalWreliZis mineraluri nedleulis instituti, Tbilisi, 0162, faliaSvilis 85, saqarTvelo.

reziume: Cordis baritSemcveli narCenebis gamdidrebaze Catarebuli winaswari kvleve- bis safuZvelze dadgenilia barit da barit-kalcitis flotaciuri koncentratebis miRe- bis SesaZlebloba. flotaciisaTvis masalis mosamzadeblad Sereul iqna dezintegraciis kombinirebuli teqnologiuri sqema, romelic uzrunvelyofs baritis da kalcitis nawilakebis sxvadasxva sisxos klasebSi gadanawilebas da flotaciis procesis seleqciurobis xarisxis amaRlebas.

sakvanZo sityvebi: Cordis baritSemcveli narCenebi; baritis seleqciuri dekripitacia; flotacia; baritis koncentrati; barit-kalcitis koncentrati.

UDC 546.72:542.61 DETERMINATION OF THE KEY FACTORS AFFECTING THE DEGREE OF REDUCTION OF BARITE CONCENTRATE OF THE MADNEULI DEPOSIT SH. Andguladze, V. Gaprindashvili, D. Eristavi, T. Kvinikadze Department of Chemical and Biological Technology, Georgian Technical University, 69 Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] At the first stage of barite reduction process devel‐ Resume: The offered basic regularities of kinetics opment, the effect of natural impurities (Al2O3, SiO2 and and mechanism of the process of reduction of barite Fe2O3) and activating additives (CaSO4, CaO and CaCO3) concentrate of the Madneuli deposit makes it much eas‐ on reducing firing process in BB furnaces was deter‐ mined. In order to improve boiling bed aerodynamic ier to find such sets of chemical and process physical pa‐ conditions, to eliminate any possible caking of material rameters which allow the process to be conducted in the and harmful side processes and to decrease losses, the most efficient way and, consequently, new rational prin‐ granulated flotation concentrate was investigated. ciples of flotobaryte recovery to be developed.

2. THE BODY OF THE ARTICLE Key words: kinetic; reduction; barite concentrate; The effect of the factors related both to reducing fir‐ Madneuli. ing (firing time, temperature, percentage and quantity of reduced gas, percent of added activating substance) and 1. INTRODUCTION to concentrate granulation (type of binding material, its The processing of flotation barite concentrate of the added percent, time and temperature of granule drying, Madneuli deposit faces some problems [1,2] both due size and degree of granule homogeneity) [3‐5] on the to fine dispersion of the material and composition caus‐ degree of barite reduction was investigated. ing a number of side reactions affecting negatively the To distinguish significant factors among the above‐ degree of barite reduction. mentioned ones, the method of random balance was used. Table1 shows two levels of the investigated factors.

Table 1 Experiment planning conditions

Coded factorial levels xi Factors ‐1 +1

ξ1 – firing temperature, ºC 800 900

ξ2 –H2/CO ratio in reducing gas 60/40 80/20

ξ3 – firing time, min. 20 40

ξ4 – gas supply by blowing to wind box , L\min 2 4

ξ5 – type of granulator Bentonite Liquid glass

ξ6 – stock granulometry, μ 200 560

ξ7 – granule homogeneity degree Strictly definite size reduced

ξ8 – percent of added activator, (CaSO4) 0 10

ξ9 – percent of added granulator 2 5

ξ10 – granule drying temperature, ºC 110 350

The effect of granule homogeneity was studied chosen such that equal quantity of SiO2 was added to through use of granules of strictly definite size in one stock both in case of bentonite and liquid glass. case (low level) and in the other case, mixed fraction To obtain a randomly balanced plan of investigated (reduced) containing granules of the size less than the factors, ξ1, ξ2, …,ξ10, were divided into two equal groups, 5 set one. The percentage of added binding substance was and half‐replicate of factorial experiment of type 2 was used for each of them (Table 2).

Table 2 Half‐replicate of complete factor experiment of type 25

First group of variables Experiment x x x x x No. 1 2 3 4 5 Second group of variables

x6 x 7 x8 x9 x10 1 + + + + + 2 + + + ‐ ‐ 3 + + ‐ + ‐ 4 + + ‐ ‐ + 5 + ‐ + + ‐ 6 + ‐ + ‐ + 7 + ‐ ‐ + + 8 + ‐ ‐ ‐ ‐ 9 ‐ + + + ‐ 10 ‐ + + ‐ + 11 ‐ + ‐ + + 12 ‐ + ‐ ‐ ‐ 13 ‐ ‐ + + + 14 ‐ ‐ + ‐ ‐ 15 ‐ ‐ ‐ + ‐ 16 ‐ ‐ ‐ ‐ +

Table 3 Plan matrix Х and experiment results

Factor

Levels and factors combinations No. Y0 YI YII YIII YIV

Experiment x1÷ x5 x6÷ x10 x1 x2 x3 x4 x 5 x 6 x 7 x8 x 9

1 14 11 ‐ ‐ + ‐ ‐ ‐ + ‐ + + 62.41 69.25 68.25 74.95 74.95 2 7 1 + ‐ ‐ + + + + + + + 57.87 59.37 66.83 78.81 72.94 3 15 9 ‐ ‐ ‐ + ‐ ‐ + + + ‐ 66.68 73.52 73.52 79.80 76.30 4 13 13 ‐ ‐ + + + ‐ ‐ + + + 59.62 66.46 66.46 72.74 72.74 5 16 15 ‐ ‐ ‐ ‐ + ‐ ‐ ‐ + ‐ 64.86 71.70 71.70 77.40 73.90 6 9 12 ‐ + + + ‐ ‐ + ‐ ‐ ‐ 70.52 70.52 77.98 77.98 74.48 7 3 14 + + ‐ + ‐ ‐ ‐ + ‐ ‐ 69.65 64.31 64.31 76.29 76.29 8 12 16 ‐ + ‐ ‐ ‐ ‐ ‐ ‐ ‐ + 57.76 57.76 65.22 70.92 70.92 9 1 3 + + + + + + + ‐ + ‐ 66.50 68.00 75.46 81.16 75.29 10 5 4 + ‐ + + ‐ + + ‐ ‐ + 77.47 72.13 72.13 77.83 75.46 11 2 8 + + + ‐ ‐ + ‐ ‐ ‐ ‐ 84.23 78.89 78.89 78.89 73.02 12 8 10 + ‐ ‐ ‐ ‐ ‐ + + ‐ + 76.05 70.71 70.71 76.99 73.49 13 6 5 + ‐ + ‐ + + ‐ + + ‐ 58.95 60.45 67.91 74.19 71.82 14 10 6 ‐ + + ‐ + + ‐ + ‐ + 59.57 59.57 67.03 79.01 73.14 15 11 7 ‐ + ‐ + + + ‐ ‐ + + 70.42 77.26 77.26 77.26 74.89 16 4 2 + ‐ ‐ ‐ + + + + ‐ ‐ 77.56 72.22 72.22 78.50 76.13

Two sub‐plans were obtained for each of the groups 3. CONCLUSION of variables and their unification provided a general plan Thus, to record data suitable for calculation of tech‐ matrix X shown in Table 3. The second and third columns nical and economic indicators of the reducing firing show sequences of lines obtained for each of the groups process, balance experiments were conducted on a of variables. According to the experiment conditions large‐scale plant of the capacity of 1 kg/hour of concen‐ (Table 2), experiments producing results shown in col‐ trate. Using the method of random balance, significant umn Y0 were implemented. factors were singled out of 10 investigated independent The Madneuli flotation barite used in the experi‐ variables, which were used to realize steepest ascent al‐ ments contains mostly the following components: BaSO4 lowing barium sulfide recovery to be increased by 10‐

‐ 82,24%, SiO2 ‐ 14,76%, Al2O3 ‐ 0,57%, Fe2O3 ‐ 0,54% . 12%. Considering all the other insignificant factors, the Significant factors were singled out using the method following conditions for realization of flotation barite of random balance by plotting a scatter diagram for each restoration process in optimal conditions are recom‐ of the 10 factors which were evaluated and checked for mended: ξ1 ‐ 950ºC; ξ2 ‐ H2/CO – 70/30; ξ3 – 20 min; ξ4 – 2 significance. L/min; ξ5 – bentonite; ξ6 ‐ 560μ; ξ7 – strictly determined 1 Modified data Y (Table 2) were derived from initial composition; ξ8 – 5%; ξ9 – 1%; ξ10 ‐ 110ºC. data Y0 by excluding the impact of singled out effects on the recovery. Successive application of the above‐ References mentioned procedure made it possible to single out all 1. Sh.Andguladze. New technology of cleaning of acid significant linear effects and a number of significant inte‐ waters of the Madneuli mine‐concentration planr. raction effects for five stages. Moscow, “Chemical technology”, 2003, No 1. Analysis of the obtained data shows an increase of 2. Sh.Andguladze, V.Gaprindashvili, et al. On the prob‐ degree of flotation barite reduction in the investigated lem of barite flotation concentrate recovery in boiling region of factorial space defined by the conditions indi‐ bed. Chemical journal of Georgia, v.7, No.2, 2007. 3. F.I.Strigunov, N.Sh.Saifulin, Z.F.Gavrilova. Recovery cated in Table 2: at higher firing temperature (ξ1); with of granulated barite concentrate. Chemical industry, use of larger material (ξ6); with lower percent of activat‐ No 6(42), 1968. ing substance (ξ ) and granulator (ξ ). The other factors 8 9 4. F.Foucot, Ching Jean Y. Chane. Utilisation du sulfure may be regarded as insignificant, having no significant ef‐ de barium ou du sulfure de strontium pour l'elimina‐ fect on the degree of flotation barite reduction. tion de metaux lourds dans les solutions sulfuriques

industrielles et procede d'elimination employant ces reactifs. Pat. 2722773 France, IPC 6 C 02 F 1/62.

uak 546.72:542.61 madneulis sabados barituli koncentratis aRdgenis xarisxsze momqme- di mniSvnelovani faqtorebis dadgena S. andRulaZe, v. gafrindaSvili, d. erisTavi, T. kvinikaZe qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, 0175, Tbilisi, kostavas 69, saqarTvelo. reziume: SemoTavazebulia madneulis barituli madnis koncentratis aRdgenis procesis meqanizmisa da kinetikis ZiriTadi kanonzomierebebi, rac mniSvnelovnad aadvilebs iseTi qimiuri da fizikuri procesebis parametrebis SerCevas, romelTa meSveobiT SeiZleba procesis efeqturobis amaRleba da flotobaritis aRdgenis racionaluri principebis SemuSaveba. sakvanZo sityvebi: kinetika; aRdgena; barituli koncentrati; madneuli.

UDC 622.762 PEGMATITES OF THE SAZANO DEPOSIT – AS THE SOURCE FOR OBTAINING OF HIGH‐POTASSIUM FELDSPAR CONCENTRATES N. Gegia, N. Shekriladze, A. Kikabidze, I. Narozauli, O. Kavtelashvili Caucasian Alexander Tvalchrelidze Institute of Mineral Resources, 85, Paliashvili st., Tbilisi, 0162, Georgia

E‐mail: [email protected] In the 50‐ies the goal of exploration conducted in Sa‐ Resume: Row material obtained from four mines of zano was to find rare metals and scattered elements, pegmatites of the Sazamo field have been studied in the such as Tantalum and Niobium. However, the prospect‐ aspect of a source of high‐potassium and potassium ing was not successful and geological works were termi‐ feldspar concentrates. It has been determined, that one nated, so that no study of pegmatite chemical composi‐ of the mines (#129) after refining meets the require‐ tion, technological properties or concentration was car‐ ments for production of fine ceramics, faience, electro‐ ried out. ceramics, porcelain, etc. Refinement is a complex The objective of the present research is to assess process involving operations of rinsing and electromag‐ Sazano Pegmatite mine perspectives with respect to netic separation of classified minerals. high‐potassium and potassium feldspar concentrates. High‐potassium feldspar, as the goods of international trade, production of which can significantly contribute Key words: feldspar; pegmatite; glimmer; rinsing; to Georgia’s economy, must be paid a special atten‐ electromagnetic separation. tion.

1. INTRODUCTION 2. THE BODY OF THE ARTICLE Feldspar is a multipurpose mineral used as a technol‐ In Sazano field pegmatite bodies are concentrated in ogical component in production of ceramic and electro‐ the basin the river Buja right affluent Mazarula and af‐ ceramic, abrasives, welding electrodes, enamel, paint fluent Kurtskhala, as well as in the vicinity of Mdivniseuli and varnish industry, rubber‐processing, soap industry area. These bodies are identical by their composition and etc. Each field of industry sets concrete requirements to structure, however, there are some distinctions, too; feldspar. In particular, potassium‐sodium feldspars in the pegmatites of Khevi and Mdivniseuli are spatially con‐ form of microcline, microcline‐perthite and orthoclase nected with grey granitoids. They are characterized by are highly valued, i.e. industrial modifications of high‐ relatively low strength, sharp contact with comprising potassium and potassium minerals, quality of which is quartz‐diorite rocks, mostly medium white grains, in rare determined by the ratio of potassium and sodium oxides cases pinkish‐white. They have identical composition and and limited mass concentration of the oxides of iron, ti‐ consist of quartz, muscovite, feldspars and mostly of pla‐ tanium, calcium, magnesium etc. gioclase. Granites, pegmatite, syenite, porcelain stones, etc. Mazarula, Kutskhala and Sakirghele pegmatites are can be considered as the source of feldspars. A. Tval‐ presented by pink or pinkish coarse‐grained stronger chrelidze, G.Gvakharia, I.Markozia, G.Zaridze and other bodies. Feldspars mainly are presented by pink micro‐ well‐known Georgian geologist‐researchers disclosed cline, while plagioclase is found rarely or not at all. quite a large amount of pegmatite bodies in Georgia, On the basis of the analysis of existing archive and which are mainly concentrated in the vicinity of the vil‐ scientific materials (1) Mazarula area can be considered lages of Shrosha (Zestaponi municipality) and Sazano as perspective one; reconnaissance and cleaning works (Terjola municipality). have been carried out at the four mines of it (#127, 128, Pegmatites found in Shrosha are thoroughly studied 129, 134). Grooved samples and characteristic samples and it has been determined, that there are 3,611 tons of have been taken, in which content of alkaline oxides C1 + C2 categories of reserves, while the exploration of have been determined at the first stage of the study (Ta‐ pegmatites, as the sources of feldspar in Sazano, have ble 1). not been carried out yet.

Table 1 Results of alkaline oxides determination in pegmatite samples Mass concentration of oxides % # Samples (Sample #/mine#) K2O/Na2O K2O+Na2O K2O Na2O 1 99/127 – 103/127 3.1‐3.46 4.3‐5.5 1.24‐1.77 7.7‐8.6 2 41/128 – 63/128 2.3‐3.86 3.3‐5.5 0.73‐3.48 6.8‐10.3 3 70/129 – 79/129 2.3‐3.86 3.1‐7.0 0.8‐3.48 7.16‐10.3 4 3/134 ‐ 23/134 3.0‐4.0 3.86‐6.0 1.0‐1.71 7.9‐9.5

Table 1 data were used for calculation of some prop‐ Based on these data, mine #129 was selected to be erties of probable average samples composed of groo‐ tested on enrichment. Two average samples 1/129 and ved samples of mines, namely sum of alkaline oxides 2/129 were composed from its grooved samples. Sample and molar concentration of potassium. 1/129 incorporates grooved samples 71/129, 72/129,

Mine #127 average sample K2O/Na2O = 1.4; 73/129 and 74/129; Sample 2/129 incorporates all the

K2O+Na2O = 8.1 ten samples of mine #129. Grooved samples entered in‐

Mine #128 average sample K2O/Na2O = 1.53; to average one with a proportion 1:1, as the length of a

K2O+Na2O = 8.02 groove is 1 m.

Mine #129 average sample K2O/Na2O = 1.76; Results of chemical analysis of samples 1/129 and

K2O+Na2O = 8.41 2/129 are given in Table 2. Results of mono‐mineral frac‐

Mine #134 average sample K2O/Na2O = 1.42; tion selected from 73/129 grooved sample of this mine

K2O+Na2O = 8.42 are also presented in this table.

Table 2 Results of chemical analysis of average samples and mono‐fraction of mine 129 pegmatite

Mass fraction of components, %

# Sample K2O/ K2O+

Na2O Na2O SiO2 Fe2O3 Al2O3 TiO2 CaO MgO MnO Na2O K2O

1 1/129 73.9 0.65 14.5 ‐ 0.23 <0.1 <0.005 2.48 7.16 2.9 9.64

2 2/129 73.7 0.73 14.8 ‐ 0.34 <0.1 <0.005 3.2 5.95 1.8 9.25

Mono‐ fraction 3 from 66.4 0.05 17.8 ‐ 0.17 <0.1 <0.005 3.2 11.6 3.62 14.8 73/129 sample

As Table 2 shows, it is possible to obtain high‐ classes are: ‐2,5+1.25 mm; ‐1.25+0.63 mm; ‐0.63+0.315 potassium product from sample 1/129, besides, its cha‐ mm. Percentages of rock‐forming minerals have been racteristics are close to mono‐fraction data. calculated for each class to determine dynamics of disin‐ To determine mineral composition of pegmatite, the tegration of a mineral. The results of analysis of mineral classes of grooved samples presenting the most realistic composition are presented in Table 3. picture have been studied by optical method; these

Table 3 Results of mineralogical analysis Mass fraction of minerals %

Classes,

# Sample te) mm ‐ Clay Rusty quartz Biotite Quartz Process (whi Feldspar Feldspar minerals Glimmer Limonite (colored) Magnetite

‐2.5+1.25 21.9 18.1 12.9 6.0 41.0 ‐ ‐ ‐ ‐ ‐ 1 70/129 ‐1.25+0.63 23.5 21.1 19.5 14.0 21.9 ‐ ‐ ‐ ‐ ‐ ‐0.63+0.315 38.8 18.2 16.7 18.3 8.0 ‐ ‐ ‐ ‐ ‐ ‐2.5+1.25 27.8 10.1 18.4 13.3 29.9 ‐ ‐ ‐ ‐ ‐ 2 ‐1.25+0.63 30.8 11.3 21.8 28.3 7.7 ‐ ‐ ‐ ‐ ‐ ‐0.63+0.315 42.8 12.5 16.3 25.0 3.2 0.2 ‐ ‐ ‐ ‐ ‐2.5+1.25 29.2 8.1 15.3 15.2 32.1 ‐ 0.1 ‐ ‐ ‐ 3 ‐1.25+0.63 31.6 11.8 18.8 26.3 11.2 0.4 ‐ ‐ ‐ ‐ ‐0.63+0.315 32.0 17.3 17.1 28.8 4.1 0.7 ‐ ‐ ‐ ‐ ‐2.5+1.25 37.3 4.4 12.6 10.2 35.3 0.2 ‐ ‐ ‐ ‐ 4 ‐1.25+0.63 42.2 7.3 23.8 17.4 8.5 0.7 0.1 ‐ ‐ ‐ ‐0.63+0.315 38.2 8.2 24.5 23.4 2.7 1.2 ‐ 0.3 0.1 ‐ ‐2.5+1.25 33.1 3.6 7.6 7.2 47.7 0.1 ‐ ‐ ‐ ‐ 5 ‐1.25+0.63 39.6 13.5 12.2 18.1 16.4 0.2 ‐ ‐ ‐ ‐ ‐0.63+0.315 45.3 13.9 13.3 24.0 3.1 0.3 ‐ ‐ ‐ ‐ 6.0 ‐ ‐ ‐2.5+1.25 27.9 10.8 5.9 49.4 ‐ ‐ ‐ 9.4 ‐ ‐ 6 ‐1.25+0.63 41.3 12.7 18.4 18.2 ‐ ‐ ‐ 11.5 ‐ ‐ ‐0.63+0.315 40.8 14.1 28.5 5.0 0.1 0.2 ‐

‐2.5+1.25 21.7 3.6 5.9 7.1 61.7 ‐ ‐ ‐ ‐ ‐ 7 ‐1.25+0.63 26.4 8.7 17.7 16.6 30.6 ‐ ‐ ‐ ‐ ‐ ‐0.63+0.315 31.3 16.1 20.3 24.0 8.2 0.1 ‐ ‐ ‐ ‐ ‐2.5+1.25 15.8 4.6 7.4 8.5 63.7 ‐ ‐ ‐ ‐ ‐ 8 ‐1.25+0.63 21.9 13.5 17.6 28.4 23.6 ‐ ‐ ‐ ‐ ‐ ‐0.63+0.315 31.1 21.3 18.8 19.8 8.5 ‐ ‐ 0.1 ‐ 0.4 ‐2.5+1.25 17.7 3.3 6.7 5.8 66.5 ‐ ‐ ‐ ‐ ‐ 9 ‐1.25+0.63 22.2 10.3 14.9 16.2 36.4 ‐ ‐ ‐ ‐ ‐ ‐0.63+0.315 29.7 13.5 19.4 26.0 11.0 0.1 ‐ 0.2 ‐ ‐ ‐2.5+1.25 14.4 4.4 4.8 8.2 68.2 ‐ ‐ ‐ ‐ ‐ 10 ‐1.25+0.63 21.7 12.3 13.6 19.5 32.9 ‐ ‐ ‐ ‐ ‐ ‐0.63+0.315 30.3 14.1 20.3 25.2 10.1 ‐ ‐ ‐ ‐ ‐

Table 3 shows, that individualization of minerals is To determine optimal value of magnetic field stren‐ possible by crushing pegmatite up to 1.25 mm grains; gth, electromagnetic separation experiments have been mass fraction of processes in the coarse‐grained mineral conducted on a mineral 100% crushed up to 2 mm gra‐ reaches 60%, meaning that it is a fine‐crystalline pegma‐ ins, as shown in Fig. 1. tite. Therefore, manual selection can not be used as an Mass concentration of electromagnetic fraction de‐ enrichment method for the tested samples. pends on magnetic field strength (Fig. 2). Mineralogical analysis revealed, that there are both Effectiveness of extraction of iron contained minerals strong and week magnetic minerals (magnetite, biotite, from feldspars increases with the decrease of grain sizes limonite, and rusty quartzes) among the testing samples. and within the class of –0.315+0.16 mm reaches its max‐ They can be extracted by electromagnetic separation, ef‐ imum 87.2 %. fectiveness of which depends on magnetic field strength Results of chemical analysis of pegmatite enrichment and grain sizes of a mineral. products are given in Table 4.

Initial mineral

Crushing

Classification

Electromagnetic separation

Magnetic fraction Nonmagnetic fraction

Fig. 1. Enrichment scheme of pegmatite by electromagnetic separation

,% 50

magnituri fraqciis gamosavali 20

Magnetic fraction output, 0

% 0 2000 4000 6000 8000 10000 12000 14000 16000 eleqtromagnituri Electromagnetic velis daZabuloba, field strength, erstedi

Fig. 2. Mass concentration of magnetic fraction depends on electromagnetic separator field strength

Table 4 Chemical composition of feldspar concentrates

Potassium Mass fraction of components, % and Sodium feldspar K2O/ SiO2 Al2O3 TiO2 Fe2O3 MgO CaO Na2O K2O Na2O

1/129 65.91 18.2 0.02 0.15 0 0.15 3.91 11.62 2.97

2/129 66.29 18.02 0.02 0.2 0.01 0.15 4.25 11.02 2.59

According to the data of Table 4, the both products product, which can be used for production of fine ceram‐ contain high concentration of potassium. Sum of alkaline ic, faience, electrotechnical ceramic, porcelain, different oxides is within the ranges 14.81‐15.27 % (norm is 8‐ fillers, etc. 12%); while potassium module exceeds 2.5% (norm is 2‐ 3%) [2]. References 1. I. Markozia (Geological Archives), 1953 3. CONCLUSION 2. V.S. Tokhtasiev, Mineral Row Materials. Feldspar Row Potassium and sodium feldspar concentrate obtained Materials. Manual. M.: “Geoinformmark”, 1998. as a result of electro magnetic enrichment of the Sazano – p 46. field pegmatites meets the requirements for high quality

uak 622.762 sazanos sabados pegmatitebi _ maRalkaliumiani mindvris Spatis koncentratebis miRebis wyaro n. gegia, n. SeyrilaZe, a. kikabiZe, i. narizauli, o. kavTelaSvili kavkasiis aleqsandre TvalWreliZis mineraluri nedleulis instituti, faliaSvilis 85, Tbilisi, 0162, saqarTvelo. reziume: Seswavlilia sazanos velis pegmatitebis oTxi ZarRvis nedleuli, rogorc ma- Ralkaliumiani da kaliumiani mindvris Spatebis koncentratebis miRebis wyaro. dadgenilia, rom erT-erTi ZarRvis (#129) nedleuli gamdidrebis Semdeg akmayofilebs moTxovnebs natifi keramikis, qaSanuris, eleqtrokeramikis, faifuris da sxvaTa warmoebisaTvis. gamdidrebis sqema kombinirebulia da moicavs morecxvisa da klasificirebuli masalis eleqtromagnituri separaciis operaciebs. sakvanZo sityvebi: mindvris Spati; pegmatiti; qarsi; morecxva; eleqtromagnituri separacia.

UDC 539.143.43 MAGNETOMETRY AND NMR STUDY OF NANOSIZED COBALT POWDERS SYNTHESIZED WITH ELECTRON‐BEAM TECHNOLOGY M. Chikovani*, А. Аkhalkatsi*, T. Gavasheli*, D. Daraselia*, D. Japaridze*, А. Shengelaya*, G. Маmniashvili**, T. Gеgechkori**, М. Оkrosashvili***, E. Kutelia***, А. Peikrishvili**** *Javakhishvili Tbilisi State University 3, Chavchavadze Av. Tbilisi 0128, Georgia; **Andronikashvili Institute of Physics, 6, Tamarashvili St. 0177, Tbilisi, Georgia; ***Georgian Technical University, 69, Kostava str. Tbilisi, 0175, Georgia; ****G. Tsulukidze Mining Institute.

E‐mail: [email protected] It is known that memory systems with high density Resume: Complex structure, magnetometry and recording capacity are in need of magnetic nanostruc‐ NMR investigation of nano‐structural cobalt powders tured materials with high magnetocrystalline anisotro‐ synthesized using electron‐beam technology was carried py, such as hexagonal close packed (HCP) Co, and less out. The developed technology makes it possible to fa‐ anisotropic face‐centered cubic (FCC) phase is more ap‐ bricate roentgen‐amorphous nanosized cobalt powders plicable in biomedicine (hyperthermia) applications [2]. of highly anisotropic HCP phase not requiring additional Therefore, the great interest is related to the develop‐ passivation measures. Magnetometry and NMR data are ment of new effective methods for synthesis of cobalt in correspondence with the results of structure mea‐ nanopowder with controllable anisotropy and compo‐ surements. sites on their basis. As it is known [1], there are following main ap‐ proaches to nanoparticle synthesis: the fabrication from Key words: nanomagnetism, NMR, magnetometry, macroscopic materials by dispersion and methods of magetic video‐pulse, electron‐beam technology, chemical synthesis related with the controlled change of material composition with stopping of new phase growth on nanosize stage. 1. INTRODUCTION The methods of MNP fabrication in gas or solid ma‐ Magnetic nanoparticles (MNP) and their composites trix using high‐energy influences on materials are con‐ on the basis of homogeneous diamagnetic matrix are sidered as physical, and methods of their synthesis in perspective materials for applications [1]. solutions are attributed to chemical ones. Magnetic properties of MNP are defined mainly by In work [3] the conditions of fabrication of highly their chemical composition, crystal lattice type and de‐ anisotropic HCP cobalt phase using the sputtering tech‐ gree of its defectivity, size and shape of MNP, their inte‐ nique were studied. The close relation between particle raction with surrounding matrix and neighbour MNPs. size and its crystallographic phase was established. Changing mean sizes of MNPs, their size distribution It turned out that HCP phase is characteristic for functions, degree of matrix space filling, phase composi‐ mean diameter (D) particles, D≥40 nm, while for par‐ tion of magnetic inclusion and surrounding them di‐ ticles with D ∼ 30 nm a mixture of HCP and FCC was ob‐ amagnetic medium it is possible to vary in a wide range served and under 20 nm the pure HCP phase was cha‐ magnetic properties of material synthesized on their ba‐ racterized with comparatively small anisotropy. sis. New technologies are currently actively developed In work [4], the HCP Co nanoparticles with D ∼ 2 nm with aim of development of new composite materials were synthesized using the silica matrix based ion im‐ with their magnetic and structure under control. For this plantation technology. aim it is more perspective to use nanomaterials with bet‐ In current work we study magnetic and structure ter controllable properties and larger specific magnetiza‐ properties of cobalt MNP, synthesized using electron‐ tion, such as Co, Fe, Ni and their alloys. Up to now the beam technology and their composite on the basis of main biomedical applications were related with iron silicon polymer matrix. Investigations of structure cha‐ oxides the synthesis of which is less subjected to control. racteristics of MNPs were carried out using X‐ray dif‐

fraction and Auger electronic spectroscopy (AEC) me‐ cuum. The metallographic analysis was carried out by thods. scanning electron microscope DSM‐960 (OPTON, Ger‐ Magnetic measurements were performed using me‐ many). thods of vibration sample magnetometry (VSM) and The composition, the thickness and the character of NMR. These methods are complementary to each oth‐ chemical bonding with metal atoms of the absorbed er, as NMR is a powerful microscopic method while layers on nanoparticles were determined according to magnetometry is attributed to macroscopic measure‐ the differential Auger‐spectra taken with the Auger‐ ment methods. electron spectrometer LAS‐2000 (RIBER, France). The spectra were registered for the same area of the sur‐ 2. THE BODY OF THE ARTICLE face and for the very same pitch of thickness of the re‐ moved layer from the surface under investigation. In this work for synthesis of nanosized cobalt and This method allows one to carry out the layer‐by‐ other metal powders electron beam technology is used layer analysis of surface, sputtering by the accelerated which according to the above introduced classification argon ions with energy 1 keV. The density of the chosen belongs to physical methods. current of ions allows to remove a layer at the rate ≤ 10 The developed by us technology of production of Å/min. nanosized powders of pure metals envisages the evapo‐ The X‐ray diffraction analysis was carried out with X‐ ration of starting materials by electron beam and fol‐ ray diffractometer HZG‐4/A‐2. In this method of nano‐ lowing condensation of the vapor on the surface of powder production the vapor produced by the electron condenser supercooled to a proper temperature. Using beam is condensed on the supercooled substrate. the developed technology we produced amorphous na‐ Therefore, the self‐diffusion of atoms precipitated on nometric powders of cobalt, nickel, titanium and mo‐ the supercooled substrate is constrained. This makes it lybdenum. Also, the nanostructural coating of cobalt possible to produce highly dispersed particles as a result and titanium are obtained on copper substrate. of direct impact of fine fragments of vapor stream on In Fig. 1 the scheme of nanopowder production the substrate. process is presented. The starting material is evaporated In Fig. 2 the image of produced cobalt powder and by electron beam (1, Fig. 1) out of water‐cooled crucible data of its electron microscopy and X‐ray analyses is (2). The formed vapor stream (3) is condensed on the presented. substrate of a special design (4). а

с Fig. 1. Scheme of cobalt nanopowder production process Fig. 2. Cobalt powder microstructure (a), electron microscopy (b) and X-ray diffraction images (с) The condensation of vapor stream occurs in vacuum (about 5 10‐2⋅Pa). Within the frames of this technology Using the developed technology mode it is possible it is impossible to eliminate completely the oxidation of to produce roentgen‐amorphous and nanosized cobalt nanosized powder even in conditions of a higher va‐ powders with grain size D ~ 100 – 150 nm. Its advantage

is the simplicity of the realization process and easiness against moisture and extreme values of temperature. of its accomplishment. The X‐ray diffraction analysis da‐ The composites were prepared by thorough mixing of ta indicate the roentgen‐amorphous nanosized struc‐ liquid polymer with cobalt MNP in 1:1 concentration. ture of synthesized metal grains. The results of Auger After this the prepared nanocomposite was polyme‐ spectroscopy analysis point additionally to the fact that rized in the outer magnetic field up to 15 КОе at room the surface layer (shell) of synthesized cobalt grains are temperature. mainly consisted of oxygen atoms, which are physically The magnetometry measurements of cobalt MNP absorbed on the surface of metal without creating of were done using Vibrating Sample Magnetometer chemical bonds with cobalt atoms contained in grain (VSM) (Cryogenic Limited, USA) allowing to carry out cores. measurements in temperature range 1.7 ÷ 293 К and in The technology does not require any preliminary magnetic field up to 5 Т. treatment of starting materials. The focused electron The VSM magnetization measurements of samples beam enables to evaporate the most refractory ele‐ were carried out in the zero‐field‐cooled (ZFC) and field‐ ments and chemical compounds, while the application cooled (FC) modes taken between ~ 3 K and 296 K for of water‐cooled copper crucibles and the carrying out different values of outer magnetic field HFC. Data were of the process under vacuum ensure a high purity of obtained first by cooling the sample from room tem‐ vapor stream and, as a result, of final product. It turns perature in zero applied field (ZFC) to lowest tempera‐ out that powders of some metals, for example cobalt ture ~ 3 K, and then a magnetic field was applied and and nickel do not require additional measures of passi‐ magnetization measured at increasing temperature. vation and hermetization. The presence of a characteristic superparamagnetic Along with structure and chemical characterization hump in the ZFC dependence points to the significant of samples, the essential significance have data on their superparamagnetic contribution in the magnetization. magnetic properties, because namely they define the The position of the maximum on the ZFC curve makes it most interesting practical applications of magnetic na‐ possible to evaluate the mean blocking temperature ТB nostructures. [2]. The synthesized cobalt MNP were stabilized in sili‐ The results of magnetization measurements are pre‐ con polymer (Akfix 100 E Siliconе) possessing excellent sented in Figs 3а,b and hysteresis data in Fig. 4. physical properties, including good adhesion, creating durable, elastic and well isolating junctions stable

Fig. 3 а) Теmperature dependence of Co nanopowder magnetization at Н=15 Ое first at cooling in zero magnetic field (ZFC), and at cooling in the same magnetic field (FC) from room temperature.

Cooling at Ho =0 ZFC - curve FC - curve b) The ZFC curve in Fig. 4а is presented in the increased scale

Fig. 4. Co nanopowder hysteresis curve at 170 К

The comparison of the obtained data with similar The decrease of echo signal intensity at switching‐on ones of work [3] allows to make the conclusion on the of MVP in intervals between RF pulses or between RF existence of significant paramagnetic contribution in pulse and echo signal is related with the breakdown of the synthesized silicon polymer composite on the Co phase coherence in a system of precessing nuclear nanopowder basis on the background of contributions moments because of change in the local nuclear fre‐ from coarse‐grained particles (such as remanent mag‐ quencies caused by hyperfine field anisotropy under the netization at cooling in zero magnetic field, and step‐ action of MVP displacing domain walls. wise change of magnetization at switching on of the po‐ The switching‐on of MVP symmetric in respect of larizing magnetic field in ZFC mode). the second RF pulse results in the fact that the first and From the location on maximum on the ZFC curve the second RF pulses successfully excite nuclei changing one could make the conclusion that the blocking tem‐ their positions in domain walls depending on their re‐ perature is about ∼ 40 K. sonance frequencies and RF field gain factor (η) [6]. At The hysteresis curve shape shows also small hystere‐ sufficiently short RF pulses the resonance frequency sis at 170 К temperature larger than ТВ. These data are in change could be neglected but the change of η results correspondence with the results of structure data on the in the decrease of echo intensity. mean diameter distribution of particles. In works [7,8] the timing and frequency spectra of For characterization of microscopic magnetic proper‐ MVP influence on the TPE signals in magnets were stu‐ ties of MNP we use the method developed in work [5] died. It was shown that the character of spectrum is where the influence of magnetic video‐pulse (MVP) field mainly defined by hyperfine field anisotropy of investi‐ on the nuclear spin echo was studied in some magnetic gated nuclei and domain wall mobilities. materials. The investigation includes the determination By recording the echo signal intensity dependence on of nuclear spin echo dependences in sample on ampli‐ the amplitude Нd (I(Нd)) one could determine quantitative‐ tude Hd and duration τm of MVP applied in the interval ly the value of MVP Нd amplitude causing the domain wall between RF pulses or between the second RF pulse and to shift by an amount equal to its effective thickness. echo signal, as well as, during RF pulse action. This fact enables simple and quality assessment of the coercive force of a sample for nuclei giving contribu‐

tion in the NMR Нd spin echo signal intensity. In Fig. 6 the experimental data are presented show‐

ing the echo signal intensity dependence on Нd for cobalt silicon polymer composite. For comparing, similar data for coarse‐grained Co powder with mean grain size D ~ 10 μ synthesized by alloying method [9] are presented, too. In work [10] was described the NMR spectrometer Fig. 5. The scheme of magnetic video‐pulse action on TPE signal. used by us and provided with the additional MVP unit The RF marks the timing and duration of RF pulse and Hd shows the capable to generate MVP with amplitudes up to 500 Oe amplitude and duration of magnetic video‐pulse. and durations up to 10 μs.

The comparison of echo intensity dependence on the tric MVP influence on MNP echo signal is lower and amplitude of exciting MVP for MNP and coarse‐grained second, the degree of asymmetric MVP influence on Co powder (Fig. 6а,b) makes it possible to reveal easily MVP echo signal is comparatively larger than one for two important peculiarities: first, the degree of symme‐ coarse‐grained Co.

Fig. 6.а) Two‐pulse echo intensity dependences on MVP amplitude Нd for symmetric () and asymmetric () influence for

Co nanopowders at 217 MHz NMR frequency (a) and for coarse‐grained cobalt at fNMR =218.5 MHz (b):

τ1 =1.3 μs, τ2 =1.5 μs, Δτ = 9 μs, τd = 3 μs. Io – echo amplitude at Hd =0.

This lower suppressive capability in Co nanopowder signal in nanopowder the larger outer magnetic fields composite as compared with Co coarse‐grained powder would be necessary. The results of echo signal intensity could be related with the significant increase of coercive measurements on the value of outer magnetic field force in that part of cobalt nanopowder which confirm these considerations (Fig.7): contributes to NMR signal. As it is known [11‐12], the decrease of cobalt powder grain size from values of the order of ~ 1 m down to ~ 150 nm is accompanied by the significant increase of coercive force of sample related with decreasing sizes and increasing role of surface effects. This fact is also reflected on the signal echo intensity dependence on the value of outer magnetic field. In coarse‐grained sample the echo signal intensity practically does not change up to magnetic field values of the order of mean demagnetizing field due to the Fig. 7. NMR echo dependence on the value of outer magnetic presence of domain walls [13]. But in case of field for Co nanopowder composite () and for coarse‐grained Co sample (). nanopowder composite the mobility and number of domain walls are essentially decreased which should be Fig. 8 presents the obtained NMR spectra of cobalt reflected on the character of I(Нo) dependence on the nanopowder composite (a) and coarse‐grained cobalt value of outer magnetic field Нo. Besides, due to powder (b) samples, along with the frequency spectra of increasing coercive force for suppressing of the echo MVP influence at symmetric and asymmetric excitations.

Fig. 8. Frequency dependence of the influence of symmetric () and asymmetric () MVP on two‐pulse echo intensity in

Co nanopowders (a) and coarse‐grained powders (b) at: τ1 = 1.1 μs, τ2= 1.2 μs, Δτ = 10 μs, τd = 2 μs, Hd =100 in Oe. 59 I/Imax ‐ Co NMR spectra, Io – echo amplitude at Hd =0.

As it is known [14] the NMR spectra of coarse‐ magnetic field into nanopowder composite according grained Co at 77 K contain two intensive peaks on the echo intensity dependence on outer dc magnetic frequencies 216 and 218.6 MHz corresponding, field pointing to a significant decrease of domain walls respectively, to nuclei arranged in the centers of domain number and their mobility in nanopowder composite as walls of FCC and the edges of domain wall of HCP compared with the coarse‐grained powder sample. phases. The shape of NMR spectra points to the fact that in Acknowledgments cobalt nanopowder prevails the HCP phase, but in The work is supported by the Georgian National coarse‐grained powder – FCC phase. This data are in Science Foundation N GNSF/ST07/7‐248 Grant. agreement with results of work [3]. References 3. CONCLUSION 1. S.P. Gubin, Yu.A. Koksharov, G.B. Khomutov, G. Yu. Complex magnetometry and NMR investigation of Yurkov. Russ. Chem. Rev. 74, N6, p.489–520 (2005). nanosized cobalt powders synthesized using electron‐ 2. H. Chiriac, A.E. Moga, C. Gherasim, J. Optoel. Ad‐ beam technology are carried out. The result of structure vanced Materials 10, 3492‐3496 (2008). investigations points to the fact that the mean grain size 3. O. Kitakami, H. Sato, Y. Shimade. Phys. Rev. B. 56, N1, is 100 150 nm. Accordingly, the magnetometry mea‐ 13849‐13854 (1997). surements data on the curve of magnetization depen‐ 4. C. de Julian Fernandez, G. Mattei, C. Sangregorio, dence on value of outer magnetic field in ZFC mode the C.Z. Battaglin, D. Gatteschi, P. Mazzoli, J. Magn. characteristic maximum manifesting the presence of su‐ Magn. Mater. 272‐276, e1235‐e1236 (2004). perparamagnetic component in cobalt nanopowder 5. L.A.Rassvetalov, A.B.Levitski. FTT, 23 ed. 11, 33‐54‐ composite with blocking temperature about ~ 40 K is ob‐ 3359, 1981. served. The results of NMR measurements of cobalt na‐ 6. M.I. Kurkin and E.A. Turov. NMR in magnetically or‐ nopowders along with the similar data for coarse‐ dered substances: Theory and applications. M.: Nau‐ grained cobalt powder composite are in correspondence ka. 1990. with data on structure and magnetometry measure‐ 7. A.M. Akhalkatsi, T.O. Gegechkori, G.I. Mamniashvili, ments, in particular, the value of outer magnetic field Z.G. Shermadini, A.N. Pogoreli, O.M. Kuz'mak. Phys. suppressing the echo signal in nanopowder was much Met. Metallogr. 105, N4, p.351‐355 (2008). higher as compared with one observed in coarse‐grained 8. A.M. Akhalkatsi, Ts.A. Gavasheli, G.I. Mamniashvili, sample pointing to the larger coercive force in nano‐ T.O. Gegechkori, M.G. Okrosashvili, A.V. powder. This fact is confirmed also by comparing data on Peikrishvili. Georgian Electronic Scientific Journals echo signal intensity dependence on the MVP amplitude (GESJ): Physics. 1(1), 35‐40 (2009). at its symmetric influence, as the MVP amplitude shifting [9]. I.G. Kiliptari, V.I. Tsifrinovich. Phys. Rev. B57, N18, the domain wall by an amount equal to its effective 11554‐11564 (1998). thickness in case of nanopowder is also considerably 10. A.M. Akhalkatsi, G.I. Mamniashvili, T.I. Sanadze. Appl. greater than one for coarse‐grained powder. Magn. Res. 15 3‐4, p.393‐399 (1998). The shape of NMP spectra of measured samples 11. A.C. Gossard, A.M. Portis, M. Rubinstein. Phys. Rev. points to the fact that the main part of nanopowder is 138, N5A, A1415‐A1421 (1965). constituted by more anisotropic HCP phase, but in the 12. G.C. Papaefthymiou. Nano Today 4, 438‐447 (2009). coarse‐grained powder – by less anisotropic FCC 13. J.H. Davis, C.W. Searle. Phys. Rev. B 14, N5, 2126‐ phase. 2136 (1976). It is interesting to note also the absence of the cha‐ 14. M. Kawakami. J. Phys. Soc. Jpn., 40, 56‐62 (1976). racteristic threshold for the penetration of outer dc

uak 539.143.43 eleqtronul-sxivuri teqnologiiT sinTezirebuli nanozomis kobaltis fxvnilebis magnetometruli da bmr gamokvlevebi m. Ciqovani*, a. axalkaci*, c. gavaSeli*, d. daraselia*, d. jafariZe*, a. Sengelaia*, g. mamniaSvili**, t. gegeWkori**, m. oqrosaSvili***, e. quTelia***, a. feiqriSvili****

*ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti. Tbilisi, 0128, WavWavaZis gamz. 3, saqarTvelo; **andronikaSvilis fizikis instituti, TamaraSvilis 6, Tbilisi, 0177, saqarTvelo; ***saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 69, saqarTvelo; ****grigol wulukiZis samTo instituti.

reziume: Catarebulia eleqtronul-sxivuri teqnologiiT sinTezirebuli kobaltis nanostruqturuli fxvnilebis kompleqsuri gamokvlevebi: struqturuli, magnetometruli da bmr. damuSavebuli teqnologia saSualebas iZleva damzaddes rentgenoamorfuli nanozomis kobaltis fxvnilebi maRal anizotropiul waxnagdacentrebul fazaSi, romlebic aRar saWiroebs damatebiTi zomebis miRebas pasivaciisaTvis. magnetometruli da bmr gazomvebi Tanxvdeba struqturul gazomvebs.

sakvanZo sityvebi: nanomagnetizmi; bmr; magnetometria; magnituri videoimpulsi; eleqtronul-sxivuri teqnologia.

UDC 504.4.054., 504.062.2 ECOLOGICAL MONITORING OF THE RIVER LIAKHVI AND EVALUATION OF THE CURRENT SITUATION M. Tabatadze*, N. Buachidze*, L. Intskirveli*, R. Kldiashvili**, G.Kuchava*, N. Beglarishvili* * Department of Natural Environment Pollution Monitoring and Forecast. Institute of Hydrometeorology, 150a, Agma- shenebeli str., Tbilisi 0114, Georgia; ** Department of Chemical and Biological Technologies, Georgian Technical University, 69 Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] 2. THE BODY OF THE ARTICLE Resume: Ecological monitoring of the Liakhvi River is For accomplishment of the research objectives first carried out, 20 ingredients defining the water quality are of all observation points were selected on the river (6 determined by use of modern physical and chemical me‐ points in total), which are located in its upper, as well as thods in previously selected 6 points. Microbiological cha‐ in lower sections (Nikozi, Variani, Shindisi, Gori). Analysis racteristics of water are studied and main contaminating samples have been taken by us during field expeditionary microorganisms are identified. It is fixed that in the re‐ works, which were carried out once in three months (ac‐ searched region especially high content of biogenic com‐ cording to seasons). In the field (near the river) by means of pounds and microorganisms is revealed in Zemo Nikozi. portative‐mobile apparatus “HORIBA” were measured physical and chemical indicators (pH, t°, conductivity, turbi‐ dimetry, salinity, dissolved oxygen). According to them we Key words: monitoring, water quality contaminat‐ expect to receive primary signal about certain alarm situa‐ ing ingredients, microbiological characteristics, biogenic tion. In the samples taken for determination (water, soil, compounds, microorganisms, collophores, E. Coli. ‐ bottom sediments), basic ions, biogenic elements (NO2 , ‐ + ‐‐‐ NO3 , NH4 , PO4 ), some radionuclides’ representatives 1. INTRODUCTION (40K,137Cs, 208Tl, 212Pb, 226Ra, 90Sr ) have been defined and, It is known that the Liakhvi River is one of the most what is the main thing, microbiological analysis of the water significant tributaries of the Mtkvari River. It flows in the (total Coli forms, Escherichia Coli and fecal streptococcus) so called South Ossetia (conflict zone) region, which is was carried out by us, since there are microbes extremely rich with natural underground waters, and through dangerous for human health and in general for any living Tskhinvali, Tamarasheni and Gori regions it flows into organism. All results of analyses were taken and processed the Mtkvari River. It is undoubted that there is an oppor‐ according to the control and support method (QAQC, tunity that mineral waters rich with radionuclides will fall QAPrD) offered by EU, and respectively averaged values of into the Liakhvi River. In addition to this, there is anthro‐ received data are given in the article in the form of tables. pogenic load (agricultural, domestic and communal • physical and chemical indicators in the field envi‐ waste waters, etc.) in Tskhinvali‐Gori section, and today ronment were determined by means of mobile appara‐ the Liakhvi River is also of great importance because of tus “HORIBA”; the fact that it flows down from the territory not con‐ + + ++ ++ ‐ • main ions (cations Na . K . Cd . Mg , anions HCO3 , trolled by us. It is also noteworthy that full monitoring of ‐ ‐‐ ‐ CO3 , SO4 , Cl ) were determined by spectrophotometric, the Liakhvi River is not carried out from the viewpoint of titrimetric and ion‐selecting chromatographic methods; its ecological estimation.

• heavy metals (Cu, Pb. Zn, Fe, Mn, Ni, Co) were de‐ The content of heavy metals is less than corresponding termined by use of atomic‐absorption method (AAS); MAC in all observation points, which is caused by water • radionuclides (40K,137Cs, 208Tl, 212Pb, 226Ra, 90Sr) were pH=8,7‐9,4. It is known that under these conditions most determined by radiochemical method by use of gamma of heavy metals experience hydrolysis and settles on the spectrometer semiconductors detector; bottom of the river. Fig. 3 shows representative content • microbiological analysis was carried out by use of of heavy metals in the Liakhvi River’s bottom sediments. membrane filtration method; The results of microbiological analysis of the Liakhvi • the received data were processed according to con‐ River water are of especial importance (Table 2, Fig. 4). trol and support method (QAQC, QAPrD). According to the standard, E. Coli should not exceed The water of the Liakhvi River is hydrocarbonate with 5000 units, while in Kveda Nikozi 20000 units (or 4 MAC) the dominance of calcium ions. Among 6 observation are observed. Then along the river current its content be‐ point by the pollution level is distinguished Kveda Nikozi, comes lesser, but near Gori is observed insignificant rise where in 2010 was constructed irrigating channel, and again. that became the reason of water damming. In particular Also especially high is the content of fecal strepto‐ the content of ammonia ions exceeds the maximum al‐ coccus in Kveda Nikozi, which reaches up to 1000 units, lowable concentration (MAC) approximately four times, while near Gori its content is equal to 180 units. then because of river self‐purification its concentration The data of total collophores analysis also give rise to reduces but tendency to rise is observed near Gori again alarm. It’s content is maximum in Kveda Nikozi, mini‐ (Table 1, Fig. 1). By the same tendency is characterized mum ‐ in Variani. biological oxygen demand (BOD5) (Fig. 2), which is cha‐ In the Liakhvi River ravine, Kveda Nikozi is singled out racteristic of the content of stable organic compound as especially polluted spot, where the impact of Tskhin‐ dissolved in water. Though, the content of other nitro‐ vali city fecal waters is clearly defined. The situation is gen and phosphorus forms is less than respective MAC, worsened by damming caused by irrigating channel con‐ but is characterized by the tendency to rise along the set struction, which creates favorable conditions for micro‐ of a current (Table 1). bes’ multiplication in the water.

Table 1 Average obtained hydrochemical data in the water of the River Liakhvi

Liakhvi‐ Liakhvi‐ Gori Gori Ingradients to be measured Nikozi Nikozi Shindisi Variani (Upper) (Lower) (Kveda) (Zeda) Transparency, sm 6 7 8 10 13 13 o Temperature , t C 14.8 15.2 15.8 16.2 19.8 20.2 Suspended particles, mg/kg 380 400 205 180 270 245 Mineralization, mg/l 220 195 180 200 240 240 Nitrogen of nitrite, mg N/L 0.002 0.002 0.010 0.015 0.020 0.025 Nitrogen of nitrate, 0.180 0.188 0.200 0.550 0.580 0.780 mg N/L Nitrogen of ammonium, 1.640 1.230 0.380 0.290 0.410 0.460 mg N/L Phosphate, mgP/l 0.002 0.002 0.010 0.020 0.023 0.026 Hydrocarbonates, mg HCO3/l 130.2 129.5 125.8 127.5 138.5 142.2 Chlorides, mg CI/l 2.620 2.440 3.330 2.880 2.420 2.324 Sulphates (soluble sulphates), 21.8 20.2 18.8 20.5 24.6 23.5 mg SO4/l Potassium, mg/l 1.3 1.4 1.5 1.8 2.2 2.4 Sodium, mg/l 7.7 7.2 8.0 7.8 8.5 9.8 Calcium, mg/l 32.5 32.4 30.8 31.8 34.5 36.7 Magnesium, mg/l 7.0 7.1 7.4 7.5 7.8 7.8

Azot of Ammonium

2 1.5 1 mgN/l 0.5

0 Niqozi 1 Noqozi 2 Shindisi Variani Gori 1 Gori 2

Fig. 1 Average content of ammonium ion in the water of the River Liakhvi

BOD5

8 7 6 5 4 mg/l 3 2 1 0 Niqozi 1 Noqozi 2 Shindisi Variani Gori 1 Gori 2

Fig. 2. Average content of BOD5 in the water of the River Liakhvi

35 30 25 20 15 Mg/Kg 10 5 0 Fe Zn Cu Ni pb Mn

Niqozi Variani Shindisi Gori

Fig 3. Average content of heavy metals in the water of the River Liakhvi.

Table 2 Average obtained data of microbiological analysis in the water of the River Liakhvi

Sampling place Total Coliforms E.Coli Fecal streptococcus In 1dm3 Liakhvi‐Nikozi 70000 26000 1200 Liakhvi‐Shindisi 12000 4600 200 Liakhvi‐Variani 10000 3500 300 Liakhvi‐Gori 13500 4200 350

E.Coli

30000 25000 20000 15000 10000 5000 0 Liaxvi-Niqozi Liaxvi-Shindisi Liaxvi-Variani liaxvi-Gori

E.Coli

Fig.4 Result of microbiological analysis in the water of the river Liaxhvi

3. CONCLUSION References The Liakhvi river water is not distinguished with es‐ 1. G.Supatashvili. Hydrochemistry of Georgia (sweet wa‐ pecially high pollution level. The content of heavy metals ters). Georgian State Univercity, Tbilisi. 2003. is less than corresponding MAC in all observation points, 2. G.Supatashvili, N.Gubadze, I.Kaviladze, G.Natsvlishvili, O.Jikia, K.Khabuliani, L.Tsagurishvili. Determination of which is caused by water pH=8,7‐9,4. In the Liakhvi river heavy metals in the Mashavera river. – Georgian Engi‐ ravine Kveda Nikozi is singled out as especially polluted neering News, N2, 2003. spot, where the impact of Tskhinvali city fecal waters is 3. G.S. Fomin, A.G. Fomin. Water. Quality and ecological clearly defined. Also, especially high is the content of safety control by international standards. Reference fecal streptococcus in Kveda Nikozi. The data of total col‐ book. Moscow, 2001. lophores analysis also give rise to alarm. Concentrations 4. U.U. Lure. Unified methods of water analysis. Chemi‐ of all other ingredients are less than the appropriate stry, 1973. 5. L.L.Demina, V.V Gordeev, L.S Fomina. Fe, Mn, Zn and MAC values. It should be noted that concentration of all Cu forms in river water and suspensions and their defined ingredients is getting bigger along the current. change in the zone river‐to‐sea water mixing (on ex‐ ample of the rivers of Black, Azov and Caspian seas ba‐ sins). Geochemistry, 1978, № 8.

uak 504.4.054., 504.062.2 mdinare liaxvis ekologiuri monitoringi da arsebuli mdgomareobis Sefaseba m. tabataZe*, n. buaCiZe*, l. inwkirveli*, r. kldiaSvili**, g. kuWava*, n. beglariSvili* *hidrometeorologiis instituti, bunebrivi garemos daWuWyianebis monitoringis da prognozirebis ganyofileba, Tbilisi, aRmaSeneblis 150a, saqarTvelo; **Tbilisis teqnikuri universiteti, qimiuri da biologiuri teqnologiebis kaTedra, Tbilisi, 0175, kostavas 69, saqarTvelo.

reziume: Catarebulia mdinare liaxvis ekologiuri monitoringi winaswar SerCeul 6 wertilSi. Tanamedrove fizikur-qimiuri meTodebis gamoyenebiT ganisazRvra wylis xarisxis ganmsazRvreli 20 ingredienti. Seswavlilia wylis mikrobiologiuri maxasiaTeblebi da identificirebulia ZiriTadi damaWuWyianebeli mikroorganizmebi. dafiqsirebulia, rom biogenuri naerTebisa da mikroorganizmebis gansakuTrebiT maRali Semecveloba aris zemo niqozSi.

sakvanZo sityvebi: monitoringi; wylis xarisxis damabinZurebeli ingredientebi; mikrobiologiuri maxasiaTeblebi; biogenuri naerTebi; mikroorganizmebi; koloforebi; E.Col.

UDC 669 FATIGUE STRENGTH OF STEEL SAMPLES BEFORE AND AFTER THEIR RECOVERY WITH ELECTRIC CONTACT WELDING‐ON OF A TAPE A. Berechikidze, M. Gogadze, M. Kurdghelia, L. Kotiashvili Department of Metallurgy, Georgian Technical University, 69 Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] ery. The aim of the presented work is determination of Resume: The object of the presented work is to es‐ steel samples endurance limit recovered with the me‐ tablish by experimental way the importance of fatigue thod of electric contact welding‐on (ECW) of steel tape. strength of samples of steel 45 and of steel tape of It is known that fatigue limit σR is corresponded with ho‐ 50XФА welded‐on electric contact (EC) welding on the rizontal section on fatigue curve i.e., peak voltage which same material with using of intermediate nickel layer. do not cause breaking at infinitely great number of cycles N. Fatigue tests were carried out on machine МУИ‐ Key words: electric contact welding‐on; fatigue 6000. Loading was realized by principle of constancy of strength. the set‐up value of sample loading during the whole pe‐ riod of testing. In such regime the load variation in the 1. INTRODUCTION tested sample happened by symmetrical cycle. Fatigue Fatigue strength is the strength of members at tests were carried out according to State Standards stresses below conventional yield point when long effect 2860‐65 “Metals. Methods of fatigue tests”. of recurrent‐variable loads causes the formation of cracks and failure. It is one of the main properties de‐ Samples were made of steel 45 (SS 1050, chemical termining long life and reliability of members. Therefore, composition, table 1) as the most wide spread at manu‐ the establishment of this characteristic after renewal of facturing machine members and facilities. Tape 50 XФА worn‐out members is an urgent problem. The effect of (SS 2283‐79, chemical composition, table 1) of thickness recovery methods for fatigue strength including the me‐ 0.5 mm was used as filler of welding‐on which found thod of electric‐contact welding‐on of a tape is less in‐ wide application at reduction of details of wide assort‐ vestigated. ment of ECW. Tape weld‐on with pressure on the sam‐ ples was realized with and without intermediate layer 2. THE BODY OF THE ARTICLE from nickel powder (Fig. 1). After recovery the worn‐out details lose definite part of fatigue strength which defines the method of recov‐

Table 1 Chemical composition of materials

Steel grade Fe C Cr Ni Mn Si V S B

Steel 45 Base 0,4-0,5 - - 0,5-0,8 0,17-0,5 - - -

50ХФА Base 0,46-0,5 0,8-0,1 <0,25 - - 0,8...0,2 - -

ПГ-СР2 5 0,2-0,5 12-15 Base - 2...3 - ≥0,04 1,5...2

Electrolysis nickel Base

100

Ferrous metals (steel and iron samples) containing carbon >0.45% were prepared with intermediate layer. The sample measures for fatigue tests are presented in Fig. 2.

Fig. 1. Samples for fatigue tests

Fig. 2. Sample measures for fatigue tests

Sample billets before welding‐on were turned for 0.2 mm by diameter. Electro contact welding‐on was realized in one passage in the mode ensuring receipt of compound with uniform strength to base metal (Fig. 3).

Fig. 3. Welded‐on samples for fatigue tests

In order to compare the received results steel 45 basis of 106 cycles. The pulse of samples was regulated samples were also testes in the initial state, cut out from by indicator with graduation 0.01 mm. The greatest a unitary block of metal. Tests were carried out on the pulse of sample did not exceed 0.03 mm.

Table 2 Test results on fatigue strength of steel 45 samples and welded‐on tapes of steel 50 XФА with intermediate nickel layer

Samples

welded‐on with steel tape 50 XФА with Steel 45 intermediate nickel layer № 6 6 σN, МПа NX10 σN, МПа NX10 1 400 0,12 371 0,10 2 370 0,20 337 0,25 3 325 1,15 297 0,70 4 250 1,51 233 1,40 5 218 2,05 183 2,05 6 197 3,50 183 3,50

101

Endurance limit of round smooth sample (kgc/mm2) Test repetition N=3 is determined by formula Test results for fatigue strength are presented in Ta‐ M 32Pl Q ble 2 and Fig.4. It is seen that fatigue strength of samples Σ= = ; P = , q W π d 3 2 with steel 50XФА cover received by ECW through inter‐ where M is bending moment constant on the whole mediate layer at optimum parameters of the mode working part of sample (between spindle carriers), makes σN=183 MPa (Fig. 4, a) which is lower by approx‐ kgc.mm; W is resistance moment of sample section, imately 7% than cyclic strength of samples of steel 45 in 2 mm ; P is load (force) applied to sample, kg; I is distance the initial state (σN=197 MPa). from the point of force application to the nearest sup‐ Some decrease of cyclic strength of the received port, mm; d is sample diameter, mm; Q is load, kg. samples compared to the samples of steel 45 happens as Test base (cycle number) when endurance limit is de‐ a result of formation of fatigue cracks in the zone of termined is calculated by formula: thermal effect under the action of cyclic loads (Fig. 4, b). N = t ∙ n ∙ 60 At fatigue failure of cover exfoliation is noted. where t is test duration from the moment of loading to the moment of test termination, h; N is nominal number of turns of the tested sample per minute.

.a) Test results on fatigue strength

b) Fractograph of the fracture of a welded‐on sample after fatigue tests

Fig. 4. Tests for fatigue strength: a – test results on fatigue strength; Samples with steel 50 XФА cover obtained with electric contact welding‐on through intermediate layer of nickel powder; Steel 45 in initial state; B ‐ Fractographs of sample fracture after fatigue tests

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3. CONCLUSION References

Thus, the results of the carried out tests show that σN 1. R.A. Latipov. Receipt of coverings from compact and of samples received by ECW of tape of 50 XФА through powder materials with electric contact welding‐on. intermediate nickel powder layer is higher approximately Welding and allied technologies in contemporary by 20% than σN received at ECW of steel wire to shafts world. V.2, Sankt‐Peterburg. Russian welding insti‐ of steel 45 [1]. This can be explained by the improve‐ tute – 2002 p.39‐43. ment of weldability of the connecting surfaces by intro‐ 2. P. Forest. Metal fatigue. M.; Mechanical engineering. duction of intermediate nickel layer, a graphite forming 1986, p.352. element, enabling carbon release from iron (cementite 3. N.V. Oleinin, S.P. Skliar. Speeded up fatigue tests. decomposition) and improvement of welding process by Kiev, “Nauka dumka”, 1985, p.303. formation of pure iron. Besides, at tape weld‐on thermal 4. Yu.M.Lakhtin, V.P. Material science. M.: Mechanical cycle effect on main metal is reduced as a result of uni‐ engineering, 1990, p.528. form heating of connection zone due to more developed 5. A.Kh. Burumkulov, L.M.Lelchuk, A.A.Ableev, V.L. De‐ contact area at the existence of powder material be‐ nisov, A.Bereshikidze. Fatigue resistance of engine Д‐ tween connecting surfaces. 21 crankshaft and estimation of its repairability. Col‐ lections of v.89, M.: 1989, p.34‐50.

uak 669 foladis nimuSebis daRlilobiTi simtkice eleqtrokontaqturi meTo- diT lentis daduRebamde da daduRebis Semdeg a. bereCikiZe, m. gogaZe, m. kurdRelia, l. kotiaSvili metalurgiis departamenti, saqarTvelos teqnikuri universiteti, 0175, Tbilisi, kostavas 77, saqarTvelo.

reziume: warmodgenili samuSaos mizania folad 45-gan damzadebuli nimuSebis daRli- lobiTi simtkicis Sefaseba. eqsperimentis gziT dadgenili unda iqnes folad 45-ze 50XФА masalis lentis eleqtrokontaqturi daduRebis meTodiT daRlilobiTi simtkicis cvlileba da agreTve daduRebis procesSi nikelis Sualeduri fenis gavlena daRlilobiT simtkiceze.

sakvanZo sityvebi: eleqtrokontaqturi daduReba; daRlilobiTi simtkice.

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UDC 621.791 PROBLEMS AND PERSPECTIVES OF UNDISTURBED CONNECTION OF MATERIALS A. Sulamanidze, A. Neverov, A. Metreveli Department of Metallurgy, Georgian Technical University, 68 Kostava str., Tbilisi 0195, Georgia.

E‐mail: [email protected] nologies, etc., to decrease the dimensions and mass of the Resume: An original power supply source of spot items. The micro welding machines do not provide the con‐ (seam) micro welding is proposed where industrial fre‐ nection of necessary quality when metal thickness is less quency sinusoidal alternative current with pairly numeri‐ than 50 microns. While the contemporary technologies cal value of half periods is used. The desired form of cur‐ demand key elements of considerably less thickness. The rent pulse is created, particularly the electrical method of latter by itself needs researches for creation of new power voltage source transformation into current source is used, sources. The similar researches have been carried out by a on expense of reactive resistance the desired family of number of authors [1,2,3]. In particular, N.Kaganov has ela‐ dropping external volt‐ampere characteristics (VAC) is ob‐ borated machines of capacitor pulse resistive micro weld‐ tained and the stability of welding process is achieved. ing. He received positive results for welding of over 50 micrometer thickness ferrous and non‐ferrous metals. While the contemporary technologies require material of Key words: undisturbed connection; stainless steel; less than 50 mcm thickness. resistance welding; micro welding; spot welding. With consideration of the above said, on the basis of welding industry direction of Georgian Technical Univer‐ 1. INTRODUCTION sity, the alternative current source of resistance welding The wide sphere of materials processing and reprocess‐ has been elaborated and created (Fig. 1a) [4]. ing implies block of disturbed, as well as, undisturbed con‐ nections. Undisturbed connection can be performed by 2. THE BODY OF THE ARTICLE gluing, soldering, welding for which electric current is wide‐ The solution of the set‐up problem become possible ly used. The current may be direct, rectified, industrial and with series connection of capacitive resistance, in the of high frequency. For receiving solid connections the resis‐ form of capacitors batteries, in the initial circuit (Fig.1 a) tance (contact) welding is distinguished with high technolo‐ It consists of 6 capacitors with volume 1, 2 and 4 mcf gical capacity. Such type macro and micro welding are dis‐ and enables to regulate from 1 to 19 with difference of 1 cerned. The technological process of resistance micro weld‐ mcf. The family of power source of volt‐ampere charac‐ ing of metal demands continuous research which is condi‐ teristics has been built (Fig. 1.b). tioned by the respective requirements of rapid develop‐ ment of micro electronics, information means, space tech‐

.a) b)

Fig.1. Resistance micro welding machine. a) Schematic diagram; b) Volt‐ampere characteristics family

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Thus, as the received diagrams indicate, for voltage were used as research objects with the capacitor pulse value to 1 volt the current force is practically un‐ and five ‐ with the proposed power source. changed. In the beginning of welding process the Fig. 3, 4 show the diagrams which are close to aver‐ growth of heated contact resistance causes the in‐ age values of results and also metallographic pictures. crease of voltage and, respectively, of heat growth. The Obviously (Fig.3), mechanical strength of samples is: subsequent growth of voltage causes the decrease of 26 kg/mm2 for welding with capacitor pulse and 80 current and, respectively, the amount of emitted heat kg/mm2 for welding with a new source. The difference is is decreased which should determine the stability of about thrice as much. the process. The mechanism becomes evident by the results of Volt‐ampere characteristic obtained by classical ma‐ metallographic analysis of seams (Fig.4), particularly the chine (Fig.1 b) shows that current growth practically does relation of welded points lengths. not cause voltage drop and its form stays sinusoidal At the same time, the asymmetricity of liquid core

(Fig.3a). should be mentioned at capacitor pulse welding when h1

The experiments prove that such VAC do not give the ≠ h2 (Fig.4a) while in the case of alternative current h1 = desired result – the members are either not welded‐on or h2 (Fig.4 b). are holed. In our opinion the latter is caused by tempera‐ Just such difference in the depths of welded point at ture excitation of the point with unlimited sinusoidal cur‐ capacitor welding causes the gluing of one of the elec‐ rent. The further experiments with using of volume resis‐ trodes on the surface of welded member. This pheno‐ tance gave the voltage of changed form (Fig.2 b, c) on menon is clearly confirmed by the point of rupture of which the section of material melting voltage is clearly liquid core binding belt perimeter (Fig 4 a). This pheno‐ seen (it is shorter in Fig.2b than in Fig. 2c). At the same menon is not observed when current limiter is used time it was established that melting section length is in di‐ (Fig.4 b). rect proportion to the length of point or provides high In the opinion of the authors the symmetrical forma‐ quality and stability of the process. tion of core in the Figure has to guarantee the decrease This was proved as a result of mechanical testing and of welding material thickness from 50 to 20 microns on metallographic research of welded seam. Five samples which the experiments are in progress now.

.a) b) c)

Fig. 2. Voltage oscillograms: a. of industrial frequency voltage; b. c. with series connection of condenser in the initial circuit of welding transformer

105

.a) b)

Fig.3. The results of mechanical testing of seam: a. with capacitor pulse; b. with series connection of capacitor battery in the initial circuit

.a) b)

Fig.4. The results of metallographic researches: a. with capacitor pulse of current; b. with series connection of capacitor

3. CONCLUSION Because of this the further decrease of capacitor The main technological difference of the developed welding thicknesses (50 mkr) is limited while the pre‐ power source from widely spread current capacitor sented method enables essential decrease of the thick‐ welding of micro welding is that here welded point is ness of welding members (to 20 mkr). ' ' strictly symmetrical to (h1 =h2 ) “hot” contact, while in the Industrial testing of the laboratory facility of the case of capacitor welding the point is displaced to the mentioned power source for stainless steel sheets of electrode of one of signs (h1 ≠ h2) and creates welding (50+50) micron thickness gave positive results. sites in “cold” (electrode) contact. At present the tests are continued for exposing tech‐ nological possibilities of the proposed power source.

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References 3. Yu.E.Paerand et al. Current pulse formation for con‐ 1. O. Gengebach. Meβtechniche Probleme beim Wider‐ tact welding. Technology and design in electron facili‐ standsschweiβen. Schweiβen und schneiden, Januar, ties, 2008, No 3, Ukraine, Donbass State Technical 1958. Zeitchrift des Deutschen. Verbandes fur University. Schweiβtechnik e.V. Dusseldorf, Harkortstraβe 23. 4. A.Sulamanidze, A.Neverov, A.Metreveli. Alternating 2. N.L.Kaganov. Design‐experimental method of detec‐ current source of resistance micro welding. Interna‐ tion of the required current pulse geometry at capa‐ tional Scientific Conference “Energetika”. Regional citor welding. Collections of MVTU, No 132, Moscow, problems and development perspectives. 21‐22 May, 1969. 2010, Kutaisi, Collection of reports, p.203‐206.

uak 621.791 masalaTa dauSleli SeerTebis problemebi da perspeqtivebi a. sulamaniZe, a. neverovi, a. metreveli metalurgis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, 0195, kostavas 69, saqarTvelo.

reziume: SemoTavazebulia wertilovani (gorgolaWovani) mikroSeduRebis originaluri kvebis wyaro, sadac gamoyenebulia samrewvelo sixSiris sinusoiduri cvladi deni naxevarperiodTa wyvili ricxviT. Seqmnilia denis impulsis sasurveli forma, kerZod, gamoyenebulia Zabvis wyaros denis wyarod gardaqmnis eleqtruli xerxi. reaqtiuli winaRobis xarjze miRebulia vardnili gare voltamperul maxasiaTebelTa (vam) sasurveli ojaxi da miRweulia SeduRebis procesis stabiluroba.

sakvanZo sityvebi: masalebi; dauSleli SeerTeba; uJangavi foladi; winaRobiT SeduReba; mikroSeduReba; wertilovani SeduReba.

107

UDC 569.67 COMBINED METHOD OF ELECTRIC CONTACT HEATING AND DIFFUSION CONNECTION OF STEEL‐ALUMINUM D. Macharadze*, D. Nozadze*, M. Okrosashvili*, T. Namicheishvili**, Ya. Tavartkiladze*, S. Bohm*** *Department of Metallurgy, Georgian Technical University, 77, Kostava str. Tbilisi 0175, Georgia; **F. Tavadze Institute of Metallurgy and Material Science; ***Braunschweig Technical University, Institute of Adhesion and Welding. Braunschweig, Germany.

E‐mail: [email protected] and introduction of new technologies may solve the prob‐ Resume: A combined method of electric contact lem of provision of industry with constructional materials. heating and diffusion connection of steel‐aluminum is The important role in perfection of metal product structure proposed which makes an essential effect on three‐ and expansion of new generation saving shapes belong to phase shaping conditions, provides better physical con‐ layered composite materials: steel‐aluminum and their al‐ tact and contact surface cleaning, formation and conser‐ loys. In shipbuilding the connections are performed in deck vation of solid setting units. Activation of contact surfac‐ superstructures from aluminum alloy AlMg3 with a metallic es is achieved more effectively and quickly than at me‐ body. Composition units of steel‐aluminum are used for chanical and vacuum treatment. Formation of physical casing of the body of flying vehicle. Connections AlMg6‐ contact and setting corresponds to contemporary con‐ 1.4878 (DIN. X12CrNiTi 18‐9) became a serious problem be‐ ceptions of solid body model and kinetics of develop‐ cause of the extension of their use in motor industry. At ment of connection strength by the data of the carried present the constructions of car body are connected by the out tests. method of combining of mechanical properties (riveting, The regimes are worked out when surfaces are com‐ clincher), bonding and spot welding which is inconsistent pressed with force (10÷15) MPa with simultaneous con‐ with the requirements on strength [1]. ductance of (5÷10) A/mm2 density current. In the Connections steel‐aluminum are characterized by in‐ process of heating for (3÷5) sec, after total crumpling and stability because of the considerable difference between settling of micropimples, the necessary level of surface ac‐ chemical‐physical and mechanical properties, thermal tivation is achieved for connection in solid state. After stresses, etc; the presence of oxide film on the surfaces termination of heating in the mode of isothermal soaking and intermetallic inclusions in transition zone are the main for (20‐30) seconds on fine surfaces formed between problems of strong connection; The necessity of mechani‐ grains setting forces are generated sufficient for formation cal purification from the films, vacuum and blasting cham‐ of strong connections. Mechanical testing is carried out in bers, interlayers between steel‐aluminum is yet compli‐ static and dynamic modes, structure and phase composi‐ cating the production of composition materials. tion in steel‐aluminum joint is determined. 2. THE BODY OF THE ARTICLE Key words: layered composites; electric contact The goal: elaboration of the method for connection AlMg ‐1.4878 of predetermined structural‐phase compo‐ heating, isothermal soaking; microstructure; micro‐ 6 sition of transition layer and mechanical properties, crea‐ hardness; mechanical properties; surface activation. tion of technological scheme on this basis. The obtained regularities may be extended to other pairs of metals (Al‐ 1. INTRODUCTION Fe, Al‐Cu, Al‐Ti) the interaction of which doesn’t require a Elaboration and improvement of the method of steel‐ special preliminary preparation of surfaces and doesn’t aluminum connection permit to reduce mass and in‐ lead to the formation of intermetallides. crease corrosion resistance, as well as to realize the Tasks: formulation of requirements (Table 1), elabora- properties inherent to each metal separately. Layered tion of connection method (fig.1), determination of tech‐ composites of magnesium bearing aluminum and stain‐ nological regimes (fig.2) and process parameters (fig.3,4,6) less alloys are widely used as adapters in steel‐aluminum on the basis of generalization of experimental [2], structur‐ structures, shipbuilding, automobile industry, aircraft cas‐ al‐phase [3] and theoretical investigations [4]. ing, etc. Rational use of metal, improvement of its quality

108

Table 1 ficient in dissimilar connections. But connection by such Characteristics of mechanical properties of connection method doesn’t satisfy the requirements on strength

AlMg6‐1.4878 (DIN. X12CrNiTi 18‐9) and especially, on plasticity without invoking of diffusion essence of the processes [5]. I N D I C A T I O N S REQUIREMENTS RESULTS The proposed combined method of electric contact Ultimate stress, δ time, 550‐660 600 heating and diffusion connection is characterized by MPa Conventional yield 400‐500 480 unique possibilities of the combination of response speed and quality. Multi‐factorial influence on surface strength, δ0,2, MPa Relative elongation, δ % 15‐20% 22 activation, effect on the processes of diffusion of alumi‐ Shear strength, δtime, >100 120 num into steel, as well as, low required parameters pre‐ MPa determine the advantages of the method (Fig.1, dotted Breaking strength, δbr, >50 75 line). MPa Press and transformer were selected, the calculation of Microhardness, HV 1200 700 thermal and energy‐power parameters was carried out, the Content, Al % 7 10 measurement means and technological equipment were Thickness, µm 10 5 created; experiments were performed at Georgian Technic‐ al University and in the Institute of Metallurgy and Mate‐ The difficulties of connection of steel‐aluminum by rials Science. According to kinetic approach the formation, melting have caused an elaboration of the methods of development and generation of connections in solid phase welding under pressure: electric contact, diffusion, ultra‐ proceed in three stages (Fig.2): sonic, condensing, etc. Fig.1 shows welding methods for • In heating process (t1‐t2) the surfaces are com‐ estimation of temperature level, pressure and temporal pressed under current growth (~50Hz) for the formation factors. of physical contact. The heat is mainly released in transi‐ tion zone since the electric resistance of oxide film is considerably higher than that of total steel‐aluminum. High current density causes the decomposition of the films on micro bulges, expends the contact surface and setting bridges. For the purpose of heating time reduc‐ tion and surface activation level increase the pulsed cur‐ rent from capacitors discharge is superposed on heating current.

• At the stage of isothermal “soaking” (t2‐t3), after the completion of crumpling and settling of micro bulges, the fine surfaces with a minimal electric resis‐ tance are formed. The current takes the maximum value at constant pressure and temperature with a duration required for development and formation of connections. Fig.1 Diagram of thermal T, power P and time t factors of welding me‐ “Critical” temperature 4200C is selected for suppressing thods [9] Dotted line ‐ current heating and diffusion connection of intermetallic formations. It is well known that at diffusion welding in vacuum • In cooling regime (t3‐t4) current disconnection is the properties of basic metals are retained. Low activa‐ combined with application of pulsed‐shock load (form‐ tion of surfaces and long‐term connection in vacuum are ing) for reducing of stressed state between steel‐ 0 the disadvantages of the method. From this viewpoint aluminum, as well as, of cooling time (from 450 C to 0 the electric contact heating, by heat release, is more ef‐ 200 C).

109

Fig.2 Cyclogram of current (I) heating and diffusion connection St‐Al ΔI‐ pulse current, ΔP ‐ shock load.

The influence of temperature in the range 400÷5000C was determined at various pressures (P=5÷40 MPa) and Fig. 4. Time‐temperature conditions. In brackets is given time at current heating. Optimal regime is dashed. time constancy. Fig.3 shows interrelations between temperature and pressure for comparison of diffusion Temperature and “delay” time effect on all charac- connection in vacuum (BC) with the data of the per‐ teristics of the connection. Time‐temperature condi‐ formed experiment (B'C'). Curve (BC) conventionally se‐ tions in the region of curves 1‐2 are well known [6], parates the zones of pressure and temperature by high where the formation of intermetallides is excluded. The (higher) and low strength properties. From Fig.1 it is evi‐ proposed optimum (dashed region) regime of lower dent that the proposed optimum (in dashed line) regime temperatures 400‐4500C, in comparison to diffusion (at P=10÷20MPa and T =400÷4500C) even at lower opt welding in vacuum, permits the considerable reduction pressure and temperature is preferential since the con‐ of time (in brackets) for the connection. The value of nection processes may be completed at temperatures by specific current (ΔI=5÷10 А/мм2) mainly determines the 100÷1500C below than melting points C' and C. rate of heating and settling and effects but moderately

on temperature. In “delay” period the current activates diffusion processes, microstructure of transition layer takes the shape of the texture extended in steel direc‐ tion. Structural and metallographic investigations of com‐

posite samples AlMg6‐1.4878 were carried out at Braun‐ schweig Institute of Welding and Adhesion in the frame of INTAS program ref.№05‐114‐5449. During the investi‐ gation of microstructure, the compositions of Fe=40% and Al=60% were established which satisfies the re‐ quirements on micro‐hardness (Fig.5). Continuous dark‐ grey interlayer is observed: thickness 5 µm, micro‐ hardness 700MPa, intermediate between aluminum (420MPa) and steel (3200MPa), which is acceptable on plasticity. Optimal combination of properties, moderate

micro‐hardness and reasonable plasticity are determined Fig.3 Temperature‐power conditions B'C'at current heating, also by Al content 10‐12% in transition zone which corre‐ Optimal regime is dashed lates with literary data [7].

110

It is well known that a nonuniform accumulation of verse nonuniformity (fig.5); just at the boundary of the magnesium between AlMg6‐1.4878 when in the joint joint there is sufficiently less magnesium than in the there is more Mg than in the depth, at temperatures depth (about 5%). It is evident that magnesium doesn’t T≥5000C [7], leads to activation of intermetallic forma‐ participate in interlayer formation and isn’t dissolved in tions. In the considered case, under the current effect at aluminum and in steel. temperature 4300C, magnesium is accumulated with re‐

Fig. 5. Microstrength, roentgenographic and spectral analyses of intermetallic connection of St‐Al system

Fig. 6 Tensile test

111

As a result of the performed experiments the possi‐ posed combined method for connection is promising for bilities of the proposed method for connection AlMg6‐ wide use in discrete (compaction) and continuous (roll‐ 1.4878 were established in accordance with the re‐ ing) production, as well as, in robotized lines and simple quirements on mechanical properties (Table 1), taking technological scheme may be easily realized at standard into account tests on stretching (Fig.6); the following means of plastic metal working and welding. 0 technological parameters are recommended: T=425 C, P=15 MPa, τ=2 min, ΔI=7.5 А/мм2 at 10% of Al and at References 5µm of transition layer thickness. 1. Diltay U., Welding and connection‐key technologies of third millennium, Automatic Welding, Kiev No‐ 3. CONCLUSION vember, 2008. Combined method for connection has a number of 2. Nozadze D.A., Namicheishvili T.G., Liluashvili Z., Ma‐ advantages: charadze D.M, Advanced Technology for Manufactur‐ • Melting‐down of connected materials is excluded; ing of Layered Composite Materials by the Method of • Operations for surface purification from oxide films Electro‐Contact Heating Under Pressure, Volume 4: are excluded; 2006 TMS Fall Extraction & Processing: Sohn Interna‐ • There is no necessity of surface protection from tional Symposium, pp.595‐598. (San Diego, California) oxidation; August 27–31, 2006. • Combination of connection processes with surface 3. Otarashvili G.G., Nozadze D.A., Namicheishvili T.G., activation means; Macharadze D.M, Research of interface of bimetal • Variation of strength and plasticity of connections if Fe‐Al by means of Auger electron spectrometer, needed; Problems of metallurgy, welding and materials • Allows to produce the constructions of complete science, №4(14), December, 2006. shapes and dimensions; 4. Tavartkiladze Y.N., Nozadze D.A., Macharadze D.M, • Multifactorial control of connection process; Kinetics of the development of the strength of mate‐ rials connection in solid phase. Collection of paper of • Reduction of connection duration in solid phase; Georgian Technical University, №1, 2008. • Simple technological scheme of production; 5. Kazakov N.F., Diffusion welding of materials, Hand‐ • Qualitative connection without intermediate inter‐ book, M., 1981. layer; 6. Larikov, L. N. Diffusion Intermetallic Compounds: Vol. • Technological cycle easily amenable to automation I, Principles. Eds. J. H. Westbrook and R.L. Fleischer. and robotization. New York, N.Y: John Wiley & Sons Ltd, pp. 757‐770. Intensification of diffusion processes is planned at 1994. heating by direct current with imposition of pulse, fre‐ 7. Ryabov V.P., Welding of aluminium and its alloys with quency and magnetic [8] fields and other known me‐ other metals, Kiev, 1983. thods of surface activation which is a subject of original 8. Rekus V.G., Butt resistance welding of the products study. This may require a more fundamental research of from homogenous and dissimilar metals under the the dependence of the variation of structure‐phase state action of external magnetic fields, Doctoral thesis, of metal in joint on technological parameters, as well as, M., 1994. an analysis of interrelationship of structural state and 9. Bochin V.A., Theory, technology, equipment of diffu‐ variation of their mechanical characteristics. The pro‐ sion welding., M.1991.

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uak 569.67 folad-aluminis eleqtrokontaqturi gaxurebis da difuziuri SeerTebis kombinirebuli meTodi d. maWaraZe*, d. nozaZe*, m. oqrosaSvili*, T. namiCeiSvili**, i. TavarTqilaZe*, s. bomi*** *saqarTvelos teqnikuri universiteti, metalurgiis departamenti, Tbilisi, 0175, kostavas 69, saqarTvelo; **f. TavaZis metalurgiis da masalaTa mecnierebebis instituti; al. yazbegis gamziris 11; Tbilisi, saqarTvelo; ***braunSveigis teqnikuri universiteti, adgeziisa da SeduRebis instituti, braunSveigi, germania.

reziume: SemoTavazebulia folad-aluminis eleqtrokontaqturi gaxurebis da difuzuri SeerTebis kombinirebuli meTodi, romelic arsebiT zegavlenas axdens myarfazuri formirebis pirobebze: uzrunvelyofs ukeTes fizikur kontaqts da sakontaqto zedapirebis moTelvas, SeWidulobis kvanZebis SekavSirebas da SenarCunebas. amasTan, sakontaqto zedapirebis aqtivacia ufro efeqturi da swrafia, vidre meqanikurad an vakuumSi damuSavebisas. eqsperementuli monacemebiT, fizikuri kontaqtis formireba da Semdgomi SekavSireba srul SesabamisobaSia myari sxeulebis Teoriul safuZvlebsa da SekavSirebis ganviTarebis kinetikur modelTan. SemuSavebuli reJimebis Tanaxmad, zedapirebis (10 ÷ 15) mpa ZaliT dawnevasTan erTad, (5 ÷ 10) a/mm2 simkriviT gaxurebis denis gatareba xdeba (3 ÷ 5) wamSi. mikrowarmonaqmnebis mTlianad moxsnisa da dasmis Semdgom miiRweva zedapirebis aqtivaciis is saWiro done, rac myar mdgomareobaSi mtkice SekavSirebis saSualebas iZleva. gaxurebis damTavrebis Semdgom (20-30) wm ganmavlobaSi, izoTermuli dayovnebis reJimSi, warmoqmnil iuvenirul zedapirebze nawilakebs Soris, viTardeba sakmarisi Zalebi mWidro kavSirebis dasamyareblad. Catarebulia meqanikuri gamocdebi statikur da dinamikur reJimebSi. gansazRvrulia struqtura da fazuri Sedgeniloba folad-aluminis SeerTebis sazRvarze.

sakvanZo sityvebi: fenovani kompozitebi; eleqtrokontaqturi gaxureba; izoTermuli dayovneba; mikrostruqtura; meqanikuri Tvisebebi; zedapiris aqtivacia.

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UDC 541.1.1‐16; 666.596 PRINCIPLES OF IN‐LINE EVALUATION OF SOLID WASTES IN GEORGIA ON EXAMPLE OF THE RUS‐ TAVI METALLURGICAL WORKS M. Gugeshidze Department of chemical and biological technologies, Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia

E‐mail: [email protected] accumulated in Georgia during many decades and at‐ Resume: On example of the waste dump of the Rus‐ tracted the attention of people working in ecologic and tavi metallurgical works the importance of carrying out economy sphere. works of in‐line evaluation of solid wastes in Georgia is The number of quite large volumes of “deposits” of considered before taking solution about their processing. potentially technogeneous raw material of Georgia com‐ It is noted that a special attention should be paid to the prises slag dumps of the Rustavi metallurgical works first two stages of in‐line evaluation – physical‐chemical (present OO “Kartuli poladi”), the Chiatura mining‐ nature and technological features. For the proof minera‐ dressing complex and the Zestafoni ferro‐alloys works logical compositions of theoretically assumed and expe‐ (present “Georgian Manganese” Ltd) and wastes of other rimentally stated materials of the Rustavi waste dump enterprises which are located on quite vast territory and open‐hearth and blast furnace slags, comparison of have detrimental effect on environment. these compositions with genuine slags received with Sooner or later the mentioned and other such mines steel and iron smelting are presented. The assumption is should become the source of technogeneous raw ma‐ done that without study of physical‐chemical nature and terial in Georgia for development of economically impor‐ technological characteristics of waste the solution made tant branches. This needs that the approach to study and about waste reclamation often gives unpredicted results. use of wastes of each enterprise be based on world ex‐ The work presents in‐line evaluation of the first two perience in this sphere. stages of wastes. The world practice proves that in order to attribute solid wastes to technogeneous raw material class it is es‐ sential to carry out preliminary measures. The complex Key words: in‐line evaluation; wastes; mineralogical of such measures are often called scientific methodic ba‐ composition; physical‐chemical nature; technological sis of solid wastes in‐line evaluation [1]. The sequence of properties. in‐line evaluation according [1] with our corrections is given in Fig.1. 1. INTRODUCTION From the given scheme it follows that for attribution The toughening of ecological safety in the world of any solid waste to technogeneous material it is neces‐ caused the increase of prices of energy and transport ta‐ sary to state its physical‐chemical nature which clearly riffs, of natural resources, land and rent prices. In these provides its properties including technogeneity. Without conditions the attention of scientists and experts is more this the following stages, rational and optimum decision frequently paid to solid wastes of production. It is stated making are impossible. that in case of rational utilization of wastes a very impor‐ The presented work concerns to the study of solid tant effect can be achieved. Their reclamation gives prod‐ wastes nature. Here on example of open‐hearth and ucts necessary for mankind which often preserving natural blast‐furnace slags at the waste dump of the Rustavi me‐ resources, improves technical‐economical indices of pro‐ tallurgical works, our approach to the study of their duction of such products. Thus, the wastes acquire the physical‐chemical nature is considered. The results re‐ functions of technogeneous raw material and their nega‐ ceived by this study and ideas about a number of issues tive action effect on environment is gradually reduced. of processing of these slags are presented. Within this context large volume solid wastes re‐ ceived by operation of a number of large enterprises had

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3. Technological scheme of major components removal 1.Physical‐chemical from wastes 6. Price of the re‐ nature ceived product 4. Equipment of technology

of major components removal 2.Technological 7. Consumer cost of properties 5. Utilization of secondary products wastes of the technology of ma‐ jor components removal

Fig. 1. The scheme of measures of attribution of wastes to technogeneous raw materials

2. THE BODY OF THE ARTICLE with environment ingredients (H2O, CO2, O2). This may re‐ By the data of 1985 [2] every year 177 thousand tons of sult in formation of new compounds, its dispersivity and ag‐ open‐hearth and 250 thousand tons of blast‐furnace slag gregate state may change. Due to all this, slag particles may was stored at slag dumps still existing in Georgia. According fractionate according to particles size and slag dump be‐ to estimated evaluation at present at slag dumps 20‐25 mln comes laminated. Slag composition and properties may tone slag is accumulated which is exposed to the action of turn different according to dump height and spread. Our environmental ingredients about 50 years. In the dump the point of view is strengthened with the world practice, for slag undergoes mechanical decomposition when coarse example in [3] it is imparted, though about self‐ decompos‐ pieces are degraded under phase transformation. Due to in‐ ing slags, the almost analogous assumptions, which before ternal and external reasons slags undergo chemical decom‐ making decision about slag processing needs detailed study position as well, the component parts of slags may interact of material located at slag dump.

Table 1 Mineralogical composition of pure and open‐hearth slag at slag dump

Minerals, group of minerals Pure slag, mass% Slag dump slag, mass% Ca hydro sulpho aluminates (Etr) ---- 6.64 Water gypsum (H‐CS) ---- 2.26 Tobermorite calcium hydrosilicate (C‐S‐H II) Ca/Si≥1.5 ---- 26.06 Braun‐millerite (Bra) 2.0 2.09 Aluminates (A) 9.75 3.16 Ca phosphates (CP) 3.11 0.58 Ca ferrites (CF) 1.93 ---- Isle‐shaped silicates (JS) 61.14 10.9 Ring‐shaped silicates (RS) 9.04 ---- Spinel‐group minerals (Shp) 4.80 35.78

Oxides (excluding SiO2) (O) 6.67 1.94 Quartz (Q) ---- 7.59 Calcium carbonate (Cc) ---- 3.00 Calcium sulphide (CS) 1.35 ---- Σ 99.99 100.00

For comparison dump slag dressed to Fe2O3 ∼ 30 mass% taken at OO “Kartuli poladi” is used.

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Table 2 Mineralogical composition of pure and blast‐furnace slag at slag dump

Minerals, group of minerals Pure slag, mass% Slag dump slag, mass% Ca hydro sulpho aluminates (Etr) ---- 2.13 Sulphides (Esp) 1.77 1.67 Double‐water gypsum (H‐CS) ---- 1.86 Tobermorite calcium hydrosilicate Ca/Si≤1.5 (C‐S‐H II) ---- 33.95 Calcium carbonate (Cc) ---- 10.01 Group silicates (GS) 81.07 16.53 Isle‐shaped silicates (JS) ---- 8.01 Calcium phosphates (CF) 0.71 0.29 Spinel‐group minerals (Shp) 2.19 12.47 Periclase (Per) ---- 1.91 Quartz (Q) ---- 7.71 Ring‐shaped silicates (RS) 11.50 ---- Frame minerals (FS) 2.76 3.46 Σ 100.00 100.00

We think very important to state how slag dump ma‐ Besides the components presented in these Tables, terials are changing under the action of environment in‐ there were noted small amounts of scrap and bead in‐ gredients. clusions which were removed from analyzed masses Using thermodynamic facilities we have estimated the with magnet. eventual effect of environment ingredients of main com‐ The above given information makes clear the distinct ponent minerals in open‐hearth and blast‐furnace slags difference between pure open‐hearth and blast‐furnace received immediately after iron and steel melting [4]. It slags and material accumulated at the dump. has been stated that the existing of such compounds are It turns out that at long “storing” in slags there ap‐ expected in slags which are impossible in composition of pear new formations the properties of which are dis‐ blast‐furnace, as well as open‐hearth furnace composition tinctly differing. The fact that slags have the functions of due to high temperature technology of iron and steel pro‐ technogeneous raw material of receiving secondary steel duction. The number of these compounds includes “free is evident but the recovered product is in different states silica” which should in pure slags be wholly included in (waste, scrap, beads, spinels, oxides) and for their sepa‐ group and isle‐shaped silicates, calcium carbonate and hy‐ ration from slag different technologies are to be used. droxide which should necessarily be decomposed at iron Slags are technological raw material in the sense of and steel melting. At interaction of pure slag components receiving binding materials, as well, since as a result of with environment ingredients in slag dump materials, on reclamation for the purpose of steel recovery the prod‐ the expense of decrease of group silicates there appear uct is received in composition of which there undoubted‐ water containing calcium silicates different form hydro‐ ly will be minerals liable to hydration and hardening (Etr, sulpho aluminates and sulphates. H‐CS, C‐S‐H1, C‐S‐H2, Bra, A, CP, CF). Their amount in Experimental research of slag samples from the Rus‐ dump of open‐hearth slag achieves to ∼ 50 mass%, while tavi slag dump with derivatographic, X‐ray phase, IR in blast‐furnace slag to ∼ 40 mass % and the separation spectroscopic and crystal optics investigation proved of this mass needs the respective technologies. that slag composition has considerably changed due to Metal bearing components are characterized with many years exposition to open air. The results of tests different magnetic susceptibility and for their total re‐ and mineralogical compositions of slags obtained by pe‐ covery magnetic field data is to be considered. Inert (non trochemical calculations of slag oxidic compositions per‐ magnetic) slag components for total recovery of metal formed in 1982‐1985 are given in Table 1 and Table 2. acquire the so called tribo‐chemical effect with slag frac‐

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tionation which may “contaminate“ the recovered met‐ iron compounds left in slag do not allow wide use of sec‐ al with inert material. Thus, magnetic field force, disper‐ ondary wastes received with reprocessing which creates sion degree, metal recovery maximum value among fac‐ additional danger in slag dump. Reprocessed, often fine tors, optimum correlation are to be found. dispersion waste heaps more actively, than before will Densities of the components of open‐hearth and interact with environment ingredients, make harmful ef‐ blast‐furnace slags at slag dump substantially differ. The fect on atmosphere, hydrosphere and ground cover and densities vary within: for silicate component is 2.2‐3.0 through them on human health. g/cm3, spinel 3.5‐4 g/ cm3, iron bearing compounds and Because the first two stages of in‐line evaluation iron 5.1‐7 g/ cm3. This allows to separate the substances scheme are not performed for improvement of the re‐ with magnetic separation as well as gravitational me‐ ceived results, in our opinion, the group of physicists‐ thods. Separation of components of open‐hearth and chemists and production engineers should be created. blast‐furnace slags can be done by particle sizes, as well. They should be entrusted within definite many tonnage Using fine sieves quite substantial part of silicate com‐ batch before reprocessing to study mineralogical com‐ ponent can be separated from slag mass. position of materials located according slag dump height It follows that the 1 and 2 stages of operative scheme and location, evaluate magnetic susceptibility, hardness, of measures allotting wastes given in fig.1 to technologi‐ granulometry of components. Only after this it will be cal raw material really substantiate optimum solution of possible to receive optimum solution about slag repro‐ the following stages. The negligence of works carried out cessing. The example of the Rustavi slag dump shows with consideration of just these stages gave low index of that before making decision about other, yet untouched total use of Rustavi slags. Only with full recovery of solid wastes reclamation, it is necessary, in our opinion, waste and partial recovery of scrap and beads the possi‐ to carry out the works in the first two stages of waste bilities of slags are not exhausted. Even more, iron and evaluation. The content is given in Fig.2.

Determination of chemi‐ cal composition according to Estimation of mag‐ waste heaps and spread netic susceptibility of waste components

Estimation of physi‐ cal‐chemical nature and technological properties of wastes Dispersion of Determination of minera‐ components of logical composition accord‐ waste and granulome‐ ing to waste heaps and tric composition of spread waste

Mechanical properties and density of waste components and waste

Fig. 2. First two stages of in‐line evaluation

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On the basis of information analysis the content of technogenic ra material. In ecological view point the the following stages are defined. treatment of waste may create the same or more to en‐ The scheme given in Fig 2, of course, is not a dogma It vironment. depends on waste technological which properties will be chosen for determination also the volume of works for es‐ References timation of physical chemical nature is depended if we 1. T.V.Bashlikova, G.A.Pakhomova, M.V.Doroshenko, consider solid waste or from the location of their storage. A.H. Makavetskas, et al. Operative estimation of Were the wastes stored several days tens of years or and consumer valu “technogenic raw material of waste dump is abandoned. In each concrete case quite mineral composition” “Technogenic raw material – concrete decision is made though in our opinion the given constructive industry” Theses of reports of city scien‐ scheme will work well in the conditions of Georgia. tific‐practical conference. M. MSCU, 2003. p.98‐99. 2. Catalogue of industrial wastes of GSSR. Georgian SSR, 3. CONCLUSION state committee on ‐techn. Provision. Tbilisi, 1985. p.15. On the example of the Rustavi metallurgical slag 3. B.S.Batalin. and of slag dumps. Journal “Priroda”, dump it is evident that from any production solid waste 2003, No 10. p.27‐32. for any useful product (products) receipt for mankind for 4. M. Gugeshidze, D.Eristavi, A.Gogishvili, A. Sarukha‐ aquiring technogenic material functions it is necessary to nishvili. Thermodynamic estimation of the possibility all stages of operative estimation of this aste. The most of interaction of dump slags of the Rustavi metallur‐ important of these stages are the first two ones . Without gical works with environment. Georgian chemical studying and stating physical chemical nature and tech‐ Journal. 2009. p.90‐92. nological properties it is impossible toconsider waste as

uak 541.1.1-16; 666.596 saqarTveloSi arsebuli myari narCenebis operatiuli Sefasebis principi rusTavis metalurgiuli sawarmos magaliTze m. gugeSiZe qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 69, saqarTvelo.

reziume: rusTavis metalurgiuli sawarmos widasayrelis magaliTze ganixileba saqarT- veloSi arsebuli myar narCenTa operatiuli Sefasebis samuSaoTa Catarebis mniSvneloba, maTi gadamuSavebis gadawyvetilebaTa miRebamde. aRiniSneba, rom gansakuTrebuli yuradReba operatiuli Sefasebis pirvel or etaps – narCenis fizikur-qimiuri bunebasa da teqnolo- giur Tvisebebs unda daeTmos. amas adasturebs Teoriulad navaraudevi da eqsperimentu- lad dadgenili rusTavis widasayreli martenisa da brZmedis widebis mineralogiuri Sed- genilobebi, maTi foladisa da Tujis gamodnobiT miRebul WeSmarit widebTan Sedareba. gamoiTqva mosazreba, rom fizikur-qimiuri bunebisa da teqnologiuri Tvisebebis Seswavlis gareSe narCenTa gadamuSavebis Sesaxeb gadawyvetilebis miRebas xSirad gauTvaliswinebeli Sedegi mosdevs. SemoTavazebulia narCenebis operatiuli Sefasebis pirveli ori etapis sa- muSaoTa Sinaarsi.

sakvanZo sityvebi: operatiuli Sefaseba; narCenebi; mineralogiuri Sedgeniloba; fizikur-qimiuri buneba; teqnologiuri Tvisebebi.

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UDC 621.7.044.7 ON DIAGNOSTICS OF PIEZOCERAMIC MEASURING TRANSDUCER Sh. Nemsadze, M. Giuashvili Department of Power Engineering, Electronics and Electroelectromechanics, Georgian Technical University, 77 Kostava str. Tbilisi 0175, Georgia

E‐mail: [email protected]; m_ [email protected] of measurements it is necessary to have information Resume: It is known that transducers made of pie‐ about amplitude‐frequency characteristics of transduc‐ zoceramic material are effective means for high preci‐ ers. This information may be acquired at short accelera‐ sion measuring of impact accelerations, which signifi‐ tion pulse action on transducer, in the direction of its cantly depends on the result of preliminary diagnostic sensitivity with registration of transducer excitation research of transducers. It is shown that very short pulse pulse and respective reaction and their further research of an object allows high precision determina‐ processing. It is evident that for effective excitation of tion of its structure, dynamic parameters and metrologi‐ high frequency transducer it is necessary that excitation cal indices. pulse duration be less or equal to the period of natural oscillation of transducer. Key words: piezoceramics; measuring transducer; When investigating dynamic characteristics of impact frequency characteristic; excitation pulse; spectral density. acceleration measuring transducers, particularly, when studying their nonlinearity they should be excited with 3 1. INTRODUCTION impulsive acceleration, the peak value of which is 10 ‐ 5 2 When studying facilities of technological or diagnos‐ 10 m/sec with longevity of 10 mcsec. tic destination intended for high speed, intensive re‐ In this respect it is urgent to design a device for in‐ gimes, different type high frequency microsized measur‐ vestigation of dynamic characteristics of measuring ing transducers are widely used. Among them very effec‐ transducer which will enable to perform full‐range diag‐ tive are piezocermic impact acceleration measuring nostics of the researched object. transducers the sensitive element of which is made of The proposed facility of magnetic‐impulse diagnostics piezoceramics. It represents electrical connections or its comprises charging device, battery of low inductance solutions which are synthesized from the mixture of dif‐ pulse capacitors, inductor in which steel waveguide is in‐ ferent oxides, carbonates and steel salts. Generally most stalled with mounted acceleration piezoceramic trans‐ of piezoceramic materials consist of titanite, lead, zirco‐ ducer, commutator with reverce switch‐in dynistor cir‐ nium solid solutions which are modified from different cuit. The device operates as follows: at impulse supply to components and additives. They also are prepared from commutator, dynistor opens and condenser batteries are titanite‐boron, titanite‐lead, and titanite‐bismuth admix‐ discharged to inductor. After the first half wave of cur‐ tures. rent passes, dynistor is closed and does not let the cur‐ For high‐quality processing of information received at rent back wave. Waveguide installed in inductor under‐ dynamic testing, the full spectrum of dynamic characteris‐ goes impulse mechanical action and researched object tics of the used transducers, including piezoceramic trans‐ mounted on its gets excited with single unipolar impulse. ducers is necessary which can be obtained with compre‐ Impulse duration is stable and does not depend on ex‐ hensive investigation of measuring transducers by means ternal factors. The value of impulse action and duration of short impact action, like investigation of electric circuits depends only on the value of charge voltage and dis‐ frequency characteristics by pulse method. charge circuit parameters. Diagnostic measuring transducer represents an elec‐ 2. THE BODY OF THE ARTICLE tro‐mechanic oscillation system which is excited with Piezoceramic impact acceleration measuring trans‐ impulsive acceleration. Differential equation to which ducers represent oscillating systems with high natural equation system of acceleration measuring transducer is oscillation frequencies. In case of their application at ddnnεεε−1 d reduced is bb++⋅⋅⋅+= bbftε (), measuring results processing for ensuring high precision nndtnn−110 dt −1 dt

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where bbnn,,...−1 b o are the coefficients determined with It is seen from this equality that spectral densities S oscillation system parameters; f ()t is excitation func‐ and S1 have similar modules, so that the spectrum of tion determined with impulsive acceleration and oscilla‐ the rest part of transducer reaction represents ampli‐ tion system parameters; ε is the reaction of measuring tude‐frequency characteristic of transducer. transducer to impulsive action. It is very important that impulsive excitation of piezoce‐ The frequencies of natural oscillations of measuring ramic impact acceleration measuring transducer of diagnos‐ transducer are determined with amplitude‐frequency tic object be very short, close to delta impulse, the spectral characteristics which represents spectral density module density of which is one. At this time spectral density of ob‐ ject response is practically the same as complex frequency of transmission function of transducer. Spectral density characteristic of object and object diagnostic study leads to of transducer transmission function is its impulsive action on reaction analysis. Sj()ω 1 Sj()ω ==ε , Sj()ω bj()ωωωnn+ b () j−1 ++ ... bj b fnn−1103. CONCLUSION where Sjf ()ω and Sjε ()ω are spectral densities of With analysis of spectral density response to very transducer excitation and reaction, respectively. short impulsive excitation of diagnostic object, piezoce‐ Complex frequency characteristic of acceleration mea‐ remic measuring transducer, it is possible to state trans‐ suring transducer, as mechanical oscillation system, can be ducer structure and to make precise determination of Sj()ω amplitude‐frequency, natural frequencies, damping, Sj()ω = ε Sj()ω determined as , where a is spec‐ nonlinearity and other metrological characteristics. Sja ()ω tral density of exciting impact acceleration of transducer. References Complex frequency characteristic of transducer is deter‐ 1. Sh. Nemsadze, G. Dolaberidze. Pulse method of de‐ mined as reaction spectral density Sj()ω = S () jω . ε termination of natural frequencies of impact measur‐ In this case in transducer response there actually is ing acceleration transducers. Metrologia. 1981, No no induced component. Transducer performs free oscil‐ 10, p.32‐35. lations with zero initial movement and initial speed. 2. V.A. Sidorov, E.V. Oshovskaya, N.A. Chentsov, Complex frequency characteristic of oscillation system is S.V.Proskuryakov. Determination of rational time of complex density of free oscillations of the system. When diagnostics. UDC 669.02/09.658.58. measuring transducer response contains induced com‐ 3. Sh. Nemsadze, G. Dolaberidze. Analysis of the ponent it is sufficient to know the duration of impact ac‐ processes in the system of mechanical waveguide‐ celeration impulse τ 0 and remove the respective initial acceleration transducer at impact motion. “Izmeri‐ section from transducer reaction, then telnaya tekhnika”, 1978. No 1, p.60‐61.

Sj10()expω =−( jωτ) ⋅ Sj( ω) .

uak 621.7.044.7 piezokeramikuli gamzomi gardamsaxis diagnostikis Sesaxeb S. nemsaZe, m. giuaSvili eleqtroenergetikis, eleqtronikis da eleqtromeqanikis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 77, saqarTvelo.

reziume: cnobilia, rom piezokeramikuli masalisagan damzadebuli gardamsaxebi warmoadgens efeqtur saSualebebs dartymiTi aCqarebebis maRali sizustiT gazomvisaTvis, romelic mniSvnelovnadaa damokidebuli gardamsaxis winaswari diagnostikuri kvlevis Se- degze. naCvenebia, rom obieqtis Zalzed xanmokle impulsuri gamokvleva saSualebas iZleva misi struqturis, dinamikuri parametrebisa da metrologiuri maxasiaTeblebis maRali si- zustiT gansazRvras.

sakvanZo sityvebi: piezokeramika; gamzomi gardamsaxi; sixSiruli maxasiaTebeli; amgznebi impulsi; speqtraluri simkvrive.

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Symposium 3 1. GEOPOLIMERS; 2. GLASS, COVERS AND ENAMELS; 3. CERAMIC AND POLIMER COMPOSITES; 4. SILICATE CERAMICS AND TRADITIONAL MATERIALS; 5. BINDING MATERIALS AND TECHNOLOGIES; 6. CERAMICS IN MOVING BODIES AND TRANSPORT.

U UDC 902.01; 552.55 CHARACTERISTICS OF LITHOLOGIC‐PETROGRAPHIC‐MINERALOGICAL COMPOSITION OF ARCHAEOLOGICAL CERAMIC WARE REVEALED ON THE TERRITORY OF GEORGIA N. Inanashvili Mining‐geology Faculty, Georgian Technical University, 77 Kostava st., Tbilisi 0175, Georgia E‐mail: [email protected] ings plastering, clayey tamped floor decking, for con‐ Resume: As a result of archaeological excavations on struction of religious and fortification facilities, etc. the territory of Georgia the ancient and unique different The artistic‐historical questions of numerous ceramic destination ceramic ware are revealed. For the purpose to wares are widely discussed in the articles of Georgian and determine their origin collaborators of the Applied Geolo‐ foreign investigators where their destination, cultural be‐ gy Department of the Georgian Technical University, longing and manufacturing period are described in detail. mainly undergraduates and doctoral candidates study the On the basis of stylistic nature, ornamental decor and lithologic‐petrographic‐mineralogical composition and shape peculiarities the local origin of the considered ce‐ possible source of the above mentioned ceramic ware raw ramics is without dispute. But it is necessary to study its materials using the modern methods. By means of scien‐ petrographic‐mineralogical composition for iden-tifica‐ tific analyses of field and laboratory study of materials, it tion of row sources as weathering products of sedimen‐ is established that most part of ceramic dishware revealed tary, volcanogenic or magmatic base rocks have the on the territory of Georgia is of local origin. For ceramic same mineral composition which is characteristic for provision natural raw material is found on the territory of stable minerals of initial rocks. That’s why ceramic wares Georgia and our ancestors have used it for production of manufactured in different regions differ by their minera‐ aesthetically perfect ceramic ware. It means that many logical composition. centuries ago the industry of ceramic ware found by us was based on local raw material. 2. THE BODY OF THE ARTICLE The laboratory study shows that ceramic ware of dif‐ Key words: archaeological, petrographic‐minera- ferent shape and destination revealed on archaeological logical composition, basalt‐porphyries, tuff breccias, ande‐ sites sometimes has the homogeneous mineralogical site‐basaltes, andesites, trachytes, plagioclase, limonite, composition or on the contrary ceramic ware of the orthoclase, quartz, pyroxene, lithocrystal clastic tuff. same type has different mineralogical composition. In our opinion homogeneous mineralogical composition is

stipulated by similarity of initial rocks and accordingly of 1. INTRODUCTION As a result of archaeological excavations on the terri‐ their weathering products. Frequently, for manufactur‐ tory of Georgia the extraordinary and various ceramic ing of ceramics, row materials are used without any ad‐ wares are revealed, such as: big size different shape and ditive in the form it is found in different regions of Geor‐ household destination ware (pitchers, jugs), various gia. On the other hand the difference in mineralogical cups, plates, printers, pipes for metal melting furnaces, composition is caused by remoteness of necessary row etc. Clay and clayey materials were widely used for build‐ materials and accordingly by their different composition.

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The lithologic‐mineralogical composition of ceramics collecting the appropriate actual material we will try to raw materials quarries frequently helps us to determine determine the sources of ceramic’s row material and the origin of manufactured ceramic ware and region of place of manufacturing. manufacturing. The presented information contains description of On the given stage the presented article does not in‐ mineralogical, petrographic and lithological composition tend to determine row materials of ceramic ware or and roentgen phase peculiarities of tiles revealed on Va‐ their manufacturing hearth. It is the object of the further ni‐Nokalakevi territory and ceramic figures from Nokala‐ study. At present we confine ourselves to description of kevi excavations. petrographic‐ mineralogical peculiarities of ceramic ware revealed in different regions of Georgia and then, after

Fig. 1. Photo of a fragment of roof tile without seal and its section

Vani tiles belong to Kolkhida plane tile type of antique epoch with scenes or without them.

Fig. 2. Photos of fragments of tiles with seals and sections

Visually tiles are fine‐grained, reddish, sometimes light color bricks. On surface the white, also dark evolvings can be seen.

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Fig.3. Fragments of tile with seal and photo of its section

Under microscope the tiles have clastic, porous struc‐ such as plagioclase, pyroxene, limonite, and hornblende ture. Represented by various material and different size and in small quantity orthoclase and quartz. fragments they are connected by clayey material. Frag‐ Mineralogical composition of ceramic figures of ani‐ mental mass dominates over connected material. mals revealed in Nokalakevi is similar. Macroscopically Fragments are represented by various effusive rocks the rock is friable, brownish. It reacts with hydrochloric such as basalts, basalt‐porphyries, tuff breccias, ande‐ acid intensively. In microscope the rock is partitioned site‐basaltes, andesites and trachytes. and represents mainly lithoclastic tuff. Fragments differ Besides the rock’s debris the separate minerals occur in their structure and composition. Among them prevail:

1. Fragments of basalt lava with microlithic main mass which is either absolutely opaque black or impregnated with iron hydroxides and is isotropic in crossed nicol;

Fig. 4. Main basalt mass and porphyry formations

2. Fragments with porphyry structure prevail. In this case the main mass is impregnated with iron hydroxides, contains microcrystal enclosures in large quantity. In some cases porphyry formations are represented with modified plagioclase. In the pores the carbonates occur.

Fig. 5. Photo of porphyry structure rock section

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3. Separate large enough grains are wholly represented by limonite, emptiness around these grains are charac‐ teristic, binding clayey mass is rust color and in crossed nicol on the whole background of isotropic rock the different size particles of quartz are dispersed. In emptiness carbonates are embedded.

Fig.6. Limonite separation in section

The mineralogical composition of two‐headed figure replaced by pelitomorphic carbonate. Separate minerals is similar to the previous sample. Microscopically the are dispersed in the rock, mainly quartz and plagioclase. rock is friable and reacts with hydrochloric acid. In mi‐ The latter is replaced with carbonate. Carbonates fill emp‐ croscope rock is similar to previous sample also but tinesses and take large area in the rock. fragments of effusive rocks (basalts, porphyrites) prevail here. The secondary processes are the same, may be 3. CONCLUSION deeper changes. The main mass of the rock is either On the basis of the analysis of the above mentioned wholly limonited or it is intensively impregnated by iron field and laboratory test materials the following conclu‐ hydroxides but the structure is conserved. In the rock sions can be done: the limonite grains occur in large enough sizes. Pyroxene The most part of ceramic ware revealed on the terri‐ occurs also in the form of porphyry evolving and it is al‐ tory of Georgia is of local origin. Natural raw material for ways fresh; plagioclase occurs seldom, is partially ceramic production is found on the territory of Georgia changed, replaced by pelitomorphic carbonate mass. and our ancestors have used it for production of aesthet‐ Carbonates occur in emptiness also. As compared with ically perfect ceramic ware. It means that many centuries previous sample quartz is very few in small size grains. ago the industry of ceramic ware was based on using the The rock’s structure is clastic and binding mass is local raw material. represented by reddish clayey material. The structure and chemical composition of minerals Lithocrystall clastic tuff, fragmental, with porous tex‐ in pottery works are practically unchangeable when ture, reacts with hydrochloride acid. In contrast to the roasting them at low temperatures (max. 700oC). previous sample studied in microscope the rock isn’t parti‐ The comparison of mineralogical‐lithologic composition tioned. The texture is porous, with clastic structure. It is of pottery works found after archaeological excavations in noteworthy that cement is represented by reddish clayey Georgia, with the open pit material is often a good basis to mass impregnated by iron hydroxide with mechanical im‐ determine their origin and source of raw materials. purities in the form of angular fine particles of quartz. The Various type pottery works are often of the same mi‐ enclosures represent effusive rocks of different type and neralogical composition that may be explained by the structure. Separate minerals are in small quantity (plagioc‐ identity of raw materials. lase and quartz). Among the effusive rocks prevail basalts, The difference in mineralogical composition of the the main mass of which is wholly or partially limonited. In same type pottery works is explained by the difference crossed nicol the mass is always isotropic. Porphyric en‐ of their raw materials. closures are seldom represented by pyroxene, it mainly is

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References 4. T.Morchadze. Ceramics of mid‐Kartli antique period 1. O.Japaridze. At the origins of Georgian history. Tbi‐ (by petrographic data), 1979. lisi, 2003, 417 p. 5. D.Akhvlediani. Roof tiles from the former Vani city. 2. O.Lortkipanidze. At the origins of old Georgian civi‐ Tbilisi, 1999. lization. Tbilisi, 2002, 239 p. 6. N.Poporadze, I.Paradashvili, D.Akhvlediani, A. Gasi‐ 3. T. Kintsurashvili. Doctor’s thesis. Scientific funda‐ tashvili. Mineralogic and petrographic study of ce‐ mentals of conservation of archaeological ceramic ramics (on example of the former Vani city). ware on example of the Atskuri Middle Bronze Era. Tbilisi, 2009.

uak 902.01; 552.55 saqarTvelos teritoriaze aRmoCenili arqeologiuri keramikuli nakeTobebis liTologiur-petrografiul-mineralogiuri Sedgenilobis daxasiaTeba n. inanaSvili geologiis departamenti, saqarTvelos teqnikuri universiteti, 0175, Tbilisi, kostavas 69, saqarTvelo.

reziume: saqarTvelos teritoriaze arqeologiuri gaTxrebis Sedegad aRmoCenilia sxvadasxva daniSnulebis uZvelesi da unikaluri keramikuli nakeTobebi. maTi warmoSobis gansazRvris mizniT, saqarTvelos teqnikuri universitetis gamoyenebiTi geologiis depar- tamentis TanamSromlebi, ZiriTadad aspirantebi da doqtorantebi, Tanamedrove meTodebis gamoyenebiT Seiswavlian keramikuli nakeTobebis liTologiur-petrografiul-mineralo- giur Semadgenlobas da am nakeTobebis warmoSobis SesaZlo wyaroebs. masalis savele da laboratoriuli Seswavlis samecniero analizis safuZvelze dadgenilia, rom saqarTve- los teritoriaze aRmoCenili keramikuli nakeTobebis didi nawili adgilobrivi warmoSo- bisaa. keramikuli nakeTobebisaTvis saWiro bunebrivi nedleuli napovnia saqarTvelos teritoriaze da Cveni winaprebi iyenebdnen am nedleuls. es niSnavs, rom mravali saukunis win arsebuli keramikuli nakeTobebis mrewveloba dafuZnebuli iyo adgilobrivi nedleulis gamoyenebaze.

sakvanZo sityvebi: arqeologia; petrografiul-mineralogiuri Sedgeniloba; bazalt- porfiri; tufobreqCia; andezit-bazalti; andeziti; traqiti; plagioklizi; limoniti; or- Toklazi; kvarci; piroqseni; tufi.

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NUCLEATION AND CRYSTALLIZATION OF MgO‐B2O3‐SiO2 GLASS U. Došler, M.M. Kržmanc, D. Suvorov “Jožef Stefan” Institute, Jamova 39, 1000 Ljubljana, Slovenia

E‐mail: [email protected] In this work we studied the influence of a TiO2 nucle‐ Resume: The nucleation and crystallization proce‐ ating agent on the crystallization mechanism and kinetics of MgO‐B O ‐SiO (MBS) glass with the composition 43 sses in MgO‐B2O3‐SiO2 (MBS) glass were studied by 2 3 2 means of non‐isothermal differential thermal analysis wt.% MgO, 35 wt.% B2O3 and 22 wt.% SiO2. Non‐ (DTA) and X‐ray diffraction (XRD). The crystallization of isothermal DTA methods were used to evaluate the crys‐ pure MBS glass was bulk with a diffusion‐controlled crys‐ tallization mechanism and determine the EG. tal growth rate (n=1.5). The addition of TiO2 facilitated the formation of nuclei and changed the crystallization 2. THE BODY OF THE ARTICLE mechanism to bulk crystallization with an increasing The glass composition, which contained 43 wt.% MgO, number of nuclei (n=4). The activation energy for the 35 wt.% B2O3 and 22 wt.% SiO2, was chosen based on pre‐ liminary studies and the phase diagram [3]. The initial re‐ crystallization of Mg2B2O5 was ∼ 400 kJ/mol, and this did agent‐grade raw materials of MgO (Sigma Aldrich, 98 %), not change significantly with the addition of TiO2. B2O3 (Alfa Aesar, 99.98 %), and SiO2 (Alfa Aesar, 99,8 %) Key words: nucleation; crystallization; Avrami ex‐ were dried and weighed in the ratio described above. After ponent; activation energy. homogenization the powder was melted at 1500 °C in a platinum crucible. The melt was held at the maximum tem‐ 1. INTRODUCTION perature for 30 minutes, where the viscosity of the melt Glass‐ceramic materials are of great interest for optical, was low enough for it to be easily poured onto a graphite electro‐optical, thermal, dielectric and other applications. In plate to avoid the occurrence of any crystallization. The microelectronic packaging various glass‐ceramic systems glass was crushed with a vibrational mill, and in order to en‐ (IBM, Motorola, Ferro etc.) are used as low‐temperature, sure complete homogenization of the glass the whole melt‐ co‐fired ceramic (LTCC) substrates [1]. The targeted LTCC ing procedure was repeated. This melting regime was found substrate materials should possess low‐permittivity, low di‐ to be sufficient to yield bubble‐free, transparent and colour‐ electric losses (high Q‐values) and good mechanical less quenched glass frit with no visible crystalline inclusions. strength. All these properties strongly depend on the de‐ The same synthesis procedure was used for the preparation gree of crystallization. For the preparation of glass‐ceramics of MBS glass with the addition of 10 wt.% of TiO2. The bulk with the desired properties, a knowledge of the crystalliza‐ samples were prepared by pouring the melt onto a graphite tion mechanisms and kinetics is of great importance. The model covered with holes that had a slightly smaller diame‐ controlled crystallization process for a certain glass compo‐ ter than the diameter of the alumina crucible used for the sition is divided into two stages: the formation of sub‐ DTA measurement. The size of the bulk samples is very im‐ microscopic nuclei and their growth into macroscopic crys‐ portant due to the equal weight of the samples, and the tals. These two stages are called nucleation and crystal‐ shape of the bulk should be flat because of the better con‐ growth, respectively. An understanding of both processes is tact with the bottom of the measuring crucible. essential for the tailoring of the properties of the glass‐ DTA measurements at different heating rates (5, 7, ceramic material. 10, 12, 15 and 20°C/min) were performed on a Jupiter Differential thermal analysis (DTA) is widely used to 449 simultaneous thermal analysis (STA) instrument study the isothermal and non‐isothermal crystallization (Netzsch, Selb, Germany) using the TG/DSC sample hold‐ kinetics of glasses. Several analytical models are availa‐ er and Al2O3 crucibles with Al2O3 as the reference ma‐ ble to evaluate the DTA results. The most commonly terial. A constant sample weight of 50 mg bulk‐glass used are the Ozawa method for the determination of the sample was used for all the measurements. The STA in‐ Avrami parameter (n), and the Kissinger, Matusita‐Sakka strument was calibrated with In, Sn, Bi, Al and Au stan‐ and Ozawa‐Chen methods for the determination of the dards. activation energy (EG) [2].

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The formation of the crystalline phase was monitored EG [4]. Matusita and Sakka proposed a modified form of by X‐ray diffraction (XRD) using a D4 Endeavor (Bruker the Kissinger equation: AXS, Karlsruhe, Germany). ⎛⎞β n ⎛mE ⎞ ln⎜⎟=− 1,052 ⎜G ⎟ + constant (2) ⎜⎟2 ⎜⎟ ⎝⎠Tp ⎝⎠RTp Theoretical background for non‐isothermal (Matusita‐Sakka method) crystallization kinetics studies where n is a numerical factor depending on the nuclea‐ The Kissinger analytical model is the most frequently tion process known as the Avrami parameter, and m is used non‐isothermal technique for determining the acti‐ the number of dimensions in which the crystal grows. vation energy for crystallization by describing the varia‐ The activation energy of the crystallization process tion of the peak crystallization temperature with the can also be defined by using the Ozawa‐Chen method. heating rate. ⎛⎞ ⎛⎞ β EG ln⎜⎟=−⎜⎟ + constant (Kissinger method) (1) d ln β mEG ⎜⎟T 2 ⎜⎟RT =−1,052 (Ozawa‐Chen method) (3) ⎝⎠p ⎝⎠p ⎛⎞1 nR d ⎜⎟ where E is the apparent activation energy for crystalliza‐ T G ⎝⎠α tion, β is the DTA heating rate, Tp is the peak crystalliza‐ When surface crystallization prevails, then m = n = 1, tion temperature and R is the gas constant. The slope of and when the number of nuclei in the glass is constant 2 the plot of ln(β/Tp ) versus 1/Tp gives the apparent acti‐ during crystallization and the DTA measurements at dif‐ vation energy of the corresponding process. The Kiss‐ ferent heating rates (β), then m = n. In the case that the inger equation is valid only when crystal growth occurs number of nuclei increases during the DTA runs and the on a fixed number of nuclei. If a majority of the nuclei number of nuclei is inversely proportional to β, then m = are formed during the DTA measurement, so that the n – 1. The values of m and n for various crystallization number of nuclei continuously varies with β then the mechanisms are summarized in Table 1. Kissinger equation does not give the right value for the

Table 1 The numerical values of n and m for various crystallization mechanisms [5]

Crystallization mechanism n m

Bulk crystallization with a constant number of nuclei

Three‐dimensional growth 3 3 Two‐dimensional growth 2 2 One‐dimensional growth 1 1 Surface crystallization 1 1

Bulk crystallization with a constant number of nuclei with a crystal growth rate proportional to t‐0.5 (diffusion controlled)

Three‐dimensional growth 1.5 1.5 Two‐dimensional growth 1 1 One‐dimensional growth 0.5 0.5

Bulk crystallization with an increasing number of nuclei

Three‐dimensional growth 4 3 Two‐dimensional growth 3 2 One‐dimensional growth 2 1

Bulk crystallization with an increasing number of nuclei with a crystal growth rate proportional to t‐0.5 (diffusion controlled)

Three‐dimensional growth 2.5 1.5 Two‐dimensional growth 2 1 One‐dimensional growth 1.5 0.5 Surface crystallization 1 1

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The Avrami exponent, n, is determined from the 3, should be a straight line, from the slope of which n can Ozawa equation: be calculated. d ln(−− ln() 1 α ) =−n (Ozawa method) (4) d ln β Results and discussion T The typical DTA curves obtained from MBS glass with where α is the volume fraction crystallized at a tempera‐ and without the addition of TiO2 are shown in Figure 1. ture T. The crystallized volume fraction α is the ratio of The glass‐transition temperature (Tg) and the single crys‐ the partial area to the total area of the crystallization tallization exothermic peak (Tp) were well defined in exotherm. From plotting ln [ln(1‐α)] versus lnβ where both DTA curves. It can be seen that the addition of TiO2 α is obtained at the same temperature from a number of slightly decreased the Tg. The XRD measurements of the crystallization exotherms, taken at different heating samples after the DTA scans revealed that the crys‐ rates, the value n is obtained. This plot, according to Eq. tallization exotherms were, in both samples, associated with the crystallization of Mg2B2O5 (Fig. 2).

Fig. 1. DTA curve of pure MBS and MBS glass with 10 wt. TiO2 at a heating rate of 10 °C/min

Fig. 2. XRD results for the MBS glass with and without 10wt.% of TiO2 as a nucleating agent

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The influence of TiO2 on the crystallization exotherm is mainly visible as a lowering of Tp, a decrease of the peak width and an increase of the peak height. The greater height of the crystallization peak of MBS glass with TiO2 compared to that of pure MBS glass indicates a larger number of nuclei, the formation of which is stimu‐ lated by the presence of the TiO2 nucleating agent. The narrowing of the peak width shows that the TiO2 en‐ hances the bulk crystallization. The Avrami exponent (n) was determined in accor‐ dance with the Ozawa equation (Eq. 4) from the DTA curves recorded with heating rates from 5 to 20 °C/min Fig. 4. Kissinger plot ((ln( β /Tp2) vs. 1000/Tp) (Fig. 3). In the case of the MBS glass without the addition for the MBS glass (β = 5, 10, 15 and 20°C/min). of TiO2 the n was close to 1.5. This indicates bulk crystal‐ lization and the formation of three‐dimensional crystals Matusita and Sakka proposed that the Kissinger from a constant number of nuclei with the crystal growth model is only valid when crystal growth occurs from a rate, which is diffusion controlled. Considering the ex‐ constant number of nuclei, otherwise incorrect values perimental errors the n of the MBS glass doped with 10 for EG are obtained. Taking into account the change of n wt.% of TiO2 can be taken as n=4. According to Table 1, with the addition of TiO2 we can assume that the crystal‐ this suggests that the dimensionality factor m is 3, con‐ lization mechanism changed from diffusion‐controlled sidering the relation m = n‐1. bulk crystallization with a constant number of nuclei in pure MBS glass (n = 1.5) to bulk crystallization with an

increasing number of nuclei (n = 4) in the MBS glass with

10 wt. % TiO2. Therefore, it is expected that the Matu‐ sita‐Sakka (Fig. 5) and Ozawa‐Chen methods lead to

more correct values of EG than the Kissinger method for the glass with the nucleating agent (Table 2). The analy‐ sis of the DTA using the former methods gave only

slightly lower values of EG (394‐400 kJ/mol) for the MBS

glass with 10 wt. % TiO2 than for pure MBS (410‐ 420kJ/mol).

Fig. 3. Plot of ln[‐ln(1‐α)] versus ln β for the determination of n.

The activation energies for both glasses were de‐ termined using the Kissinger, Matusita and Ozawa‐ Chen methods (Table 2). Fig. 3 shows the plots of ln(β/Tp2) against 1/Tp for pure MBS glass. The slopes of the best fit based on li‐ near regression were used to calculate the activation energy for crystallization. The corresponding EG deter‐ mined by the Kissinger method was 410 kJ/mol. The n 2 Fig. 5. The Matusita‐Sakka plot (ln(β /Tp ) vs. Matusita and Ozawa‐Chen methods gave very similar 1000/Tp) for the MBS glass with the addition values of 411 and 420 kJ/mol, respectively (Table 2). of 10 wt.% of TiO2 (β = 5, 7, 10, 12 and 15 °C/min)

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Table 2 tion and stimulates the formation of nuclei during the Comparison of the activation energies calculated heating process. Different analytical methods (Matu‐ from different analytical methods for MBS glass ssita‐Sakka and Ozawa‐Chen) lead to very similar values with and without 10 wt.% of TiO2. of E (~400 kJ/mol) for the crystallization of Mg B O G 2 2 5 from both MBS glasses.

References 1. C.R. Chang, J.H. Jean. Crystallization kinetics and mechanism of low‐dielectric, low‐temperature,

cofirable CaO‐B2O3‐SiO2 glass‐ceramics. Journal of the American Ceramic Society. 82, [7] 1725–1732 (1999). 2. R. Iordanova, E. Lefterova, I. Uzunov, D. Klissurshi.

Non‐isothermal crystallization kinetics of V2O5– MoO –Bi O glasses. Journal of Thermal Analysis Ca‐ 3 2 3 lorimetry. 70, 393–404 (2002). 3. CONCLUSION 3. H.J. Kuzel. Untersuchung des dreistoffsystems MgO –

The crystallization of MBS glass and the influence of B2O3 – SiO2. Neues Jahrbuch für Mineralogie 100, [3] the TiO2 nucleating agent on the crystallization mecha‐ 322‐338 (1963). nisms and kinetics were studied by non‐isothermal DTA 4. X.J. Xu, C.S. Ray, D.E. Day. Nucleation and methods. The variation of the Avrami exponent n from crystallization of Na2O∙2CaO∙3SiO2 glass by differential 1.5 to 4 indicates a change in the crystallization mecha‐ thermal analysis. Journal of the American Ceramic nism from diffusion‐controlled bulk crystallization with a Society 74, [5] 909–914 (1991). constant number of nuclei in pure MBS glass to bulk 5. I.W. Donald. Crystallization kinetics of a lithium zinc crystallization with an increasing number of nuclei in the silicate glass studied by DTA and DSC. Journal of Non‐ MBS glass with TiO2..The presence of a high concentra‐ Crystalline Solids 345&346, 120–126 (2004). tion of TiO2 most probably facilitates the bulk crystalliza‐

MgO-B2O3-SiO2 minis nukleacia da kristalizacia u. dosleri, m. maCek krJmansi, d.suvorovi “jozef stefanis” instituti, Jamovas 39, lubliana, 1000, slovenia. reziume: minakeramikuli masalebi aris polikristaluri myari nivTiereba, romelic mzaddeba minis regulirebuli kristalizaciiT. kristalizaciis procesi or etapad iyofa: nukleaciis da kristalis warmoqmnis. minakeramikis Tvisebebis dasadgenad aucilebelia orive procesis Seswavla. minis kristalizaciis ganmartebisTvis aucilebel parametrebs Sorisaa temperaturuli intervali, romelSic nukleacia SeiZleba moxdes, maqsimaluri nukleaciis temperatura, aqtivaciis energia da kristalis zrdis xarisxi. diferencialuri Termuli analizi (DTA) farTod gamoiyeneba minis izoTermuli da araizoTermuli kristalizaciis Sesaswavlad. arsebobs ramdenime analitikuri modeli diferencialuri Termuli analizis Sedegebis Sesaswavlad. ufro xSirad ixmareba n-is gansazRvris ozamas (avramis parametri) an kisinjeris da matusitas (aqtivaciis energia) meTodi. mocemul naSromSi MgO-B2O3-SiO2 minis nukleaciis da kristalizaciis procesebi Seiswavleba araizoTermuli diferencialuri Termuli analiziT, rastruli eleqtronuli mikroskopiiT da rentgenodifraqciiT. Cven SeviswavleT kompozitis da nukleaciis reagentis (TiO2) koncentraciis gavlena kristalizaciis kinetikaze. (TiO2) moqmedebs maqsimaluri nukleaciis temperaturasa da aqtivaciis kinetikaze. ufro metic, (TiO2) damatebiT kristalizaciis meqanizmi gadadis difuzur-kontrolirebadi moculobiTi kristalizaciidan atomebis mudmivi raodenobiT moculobiT kristalizaciaSi atomebis gazrdili raodenobiT. agreTve Seswavlilia da ganxiluli gansxvaveba minis fxvnilis da ZiriTadi minis kristalizaciebs Soris. sakvanZo sityvebi: nukleacia; kristalizacia; avramis eqsponenti; aqtivaciis energia.

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ANALYTICAL AND NUMERICAL CALCULATIONS OF THE THERMAL CONDUCTIVITY OF Al2O3 – ZrO2 COMPOSITE CERAMICS J. Hostaša, W. Pabst Department of Glass and Ceramics, Institute of Chemical Technology, Prague (ICT Prague), Prague, Czech Republic

E‐mail: [email protected] ing on the microstructural information available (e.g. the Resume: Thermal conductivity is one of the essential generally valid Wiener bounds or the Hashin‐Shtrikman properties of ceramic materials with respect to their ap‐ bounds valid for isotropic microstructures). However, in plication as insulation materials, refractories or materials cases where the difference between the thermal conduc‐ for electronics. The topic of this contribution is the estima‐ tivities of the constituent phases is high (corresponding to a high phase contrast), it is often useful to apply mod‐ tion and calculation of the thermal conductivity of Al2O3 – el‐based analytical or numerical approaches to estimate ZrO2 composite ceramics using analytical and numerical approaches. Both the dependence of thermal conductivity the effective thermal conductivity of the material. For on the composition and on the grain size is taken into ac‐ example, in the case of Al2O3 – ZrO2 composites, the count for two‐phase composite models. In the first part, phase contrast between the pure oxides is approximately an analytical solution of the dependence on the composi‐ one order of magnitude [2], and thus the difference be‐ tion based upon the micromechanical bounds (Hashin‐ tween the upper and lower Hashin‐Shtrikman bounds is Shtrikman bounds) and on the grain size based upon the too high for these bounds to provide practically useful phase mixture approach is presented with the use of a predictions. relatively new relation (sigmoidal average). For the esti‐ For the dependence on grain size there is no rigorous mation of the latter a model of grain boundary as a sepa‐ estimation within micromechanics that would be of gen‐ rate phase of thickness 1 nm and thermal conductivity eral validity for any kind of microstructure and therefore close to that of glasses and amorphous dielectrics, viz. 1.1 it is reasonable to use simple (geometrically) models. W/mK is assumed. The second part presents numerical In the work presented hereby both the analytical cal‐ calculations of thermal conductivity via the finite element culations based upon rigorous micromechanical bounds method (COMSOL Multiphysics software) applied on the and numerical simulations were carried out and the re‐ model geometry used in the analytical solution and on sults were compared with micromechanical bounds and randomly generated microstructures. The results of both literature data, when available. In the case of depen‐ calculation methods are compared with one another and dence on grain size, ideal interfaces with no thermal re‐ also with experimental data. The presented analytical and sistance were assumed, as the effect of grain boundaries was taken into account via the phase mixture approach. numerical approaches are not only designed for the Al2O3

– ZrO2 system, but are of general use for any isotropic par‐ ticulate composite material. 2. THE BODY OF THE ARTICLE Micromechanical bounds Similar to other material properties (e.g. elastic mod‐ Key words: alumina; Beran bounds; composites; fi‐ uli), the effective thermal conductivity of heterogeneous nite element method; grain boundary; grain size; Hashin‐ materials is bounded by rigorous micromechanical Shtrikman bounds; nanocrystalline ceramics; numerical bounds [1]. The three most popular types of bounds (viz. simulations; sigmoidal average; thermal conductivity; one‐, two‐ and three‐point bounds) are shown here for Wiener bounds; zirconia. comparison with the results calculated in this work, in the form valid for two‐phase composites. 1. INTRODUCTION When volume fractions are the only information Calculation of the effective thermal conductivity of known about the microstructure, Wiener bounds (one‐ heterogeneous materials in dependence on their compo‐ point bonds) [1] can be calculated using expressions sition is not a trivial problem, as it depends critically on kkk+ =+φ φ (1) the microstructure [1]. Of course it is possible to deter‐ W 11 2 2 mine upper and lower micromechanical bounds, depend‐ and

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− kk12 composites, is bounded by the Hashin‐Shtrikman kW = , (2) φφ12kk+ 21 bounds. Since for polycrystalline materials the dominat‐ ing phase can be expected to determine the overall where φ is the volume fraction of phase i (note that for i property, an S‐shaped dependence on the phase volume two‐phase materials φφ12+=1 ), ki its thermal conduc‐ fractions can be expected. The simplest relation for de‐ tivity and the superscripts + and – denote the upper scribing such an S‐shaped dependence is the recently bound and lower bound, respectively. proposed sigmoidal average +− When isotropy of the material (microstructure) can kkkσ =+φ12φ , (7) be assumed, Hashin‐Shtrikman (two‐point) bounds [1] where we insert the upper and lower Hashin‐Shtrik‐ can be calculated, + − man bound for k and k , respectively (see [3]). For 2 + φφ12()kk 1− 2 the analytical estimations, the following thermal conduc‐ kkkHS =+φφ11 2 2 − , (3) 3kkk1112−−φ () tivity values were used: 33 W/mK for Al2O3 and 2.9 W/mK

2 for t‐ZrO2 (3Y‐TZP), both presented in [2] as typical values. − φφ12()kk 1− 2 kkkHS =+φφ11 2 2 − . (4) Figure 1 shows the results of the analytical calculation 3kkk2212+−φ () compared to aforementioned rigorous bounds in depen‐

dence on the ZrO2 content in the ceramics. It is evident Even tighter than the aforementioned bounds are that the sigmoidal average describes an S‐shaped curve Beran (three‐point) bounds [1], which can be obtained that lies within the two‐point (Hashin‐Shtrikman) bounds for specific types of microstructures. For two‐phase mi‐ and (to a satisfactory approximation) also within the crostructures they have the form three‐point (Beran) bounds for SCMs with cubic cells. 2 φφ12()kk 2− 1 kkk+ =+φφ − , (5) B 11 2 2 Analytical approach for the grain size dependence of φφ12kk++ 212() ξξ 11 kk + 22

2 thermal conductivity φφ12()kk 2− 1 kkk− =+φφ − , (6) In classical micromechanical approaches grain size is B 11 2 2 2 φφkk++ not taken into account. It is well known, however, that 12 21 ξ ξ 12+ some properties exhibit a dependence on the grain size. kk 12 In particular, the thermal conductivity of nanocrystalline where ξi is a dimensionless microstructure parameter materials (with grain sizes below 100 nm) can be signifi‐ from the interval 0;1 , for which the equation cantly below that of their coarser‐grained counterparts. This phenomenon finds a plausible explanation when the ξξ12+=1 applies (for general composites ∑ξi = 1). In i existence of a grain boundary phase (GB phase) with de‐ the case of some special microstructures (symmetric‐cell fined properties is postulated that occupies the grain materials SCMs), this parameter is known as a function boundaries (GBs) with small but finite thickness. Thus, of the phase volume fractions. In particular, for two‐ the grain size dependence of thermal conductivity can be phase SCMs randomly occupied with (two types of) cubic modeled for a monodisperse system by calculating the cells the relation between the three‐point parameter ξ2 GB phase volume fractions for a specific cell geometry (e.g. cubic) in dependence of the cell size. Since the and the volume fractions is ξφφ212=+0.11882 0.88118 . structure of GBs is often assumed to be glass‐like, it is SCMs can be expected to be good approximations for reasonable to assume also the GB properties to be glass‐ (isotropic) “grainy” microstructures consisting of two like. Thus, in the approach presented here, the grain size phases, i.e. dense (non‐porous) polycrystalline compo‐ is taken into account via the grain boundary phase. For site materials with two types of (isometric or randomly the calculation presented here a simple core‐shell model oriented anisometric) grains of similar size. with cubic geometry was used, consisting of crystalline

core and a grain boundary shell phase (see Fig. 2). The Analytical approach for the effective thermal con‐ grain boundary is regarded as a separate phase of thick‐ ductivity of alumina‐zirconia composites ness 1 nm with a thermal conductivity corresponding to As mentioned above, the effective thermal conduc‐ that of glasses or amorphous dielectrics, i.e. 1.1 W/mK tivity of isotropic two‐phase materials, e.g. Al2O3‐ZrO2 (which is a more or less universal value). The estimated

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grain boundary thickness is a parameter of high influ‐ measured or estimated values for solid‐state sintered ce‐ ence, especially in the area of smaller grain sizes. The ramics range from 0.5 to 2 nm. In order to make the re‐ value can be experimentally measured by HRTEM, e.g. in sults of this work comparable to results obtained with

[4] the value for Al2O3 – ZrO2 composite ceramics has other grain shapes, the volume equivalent diameter was been determined to be about 2 nm, and commonly used as grain size value in the present calculations.

5 Effective thermal conductivity [W/mK] conductivity thermal Effective 0 00.20.40.60.81 ZrO volume fraction [1] 2 Fig. 1. Effective thermal conductivity of Al2O3 – ZrO2 composite ceramics vs. the volume fraction of ZrO2; upper and lower Wiener bounds (dotted curves), Hashin‐Shtrikman bounds (dashed curves), Beran bounds (full curves) and the sigmoidal average of the Hashin‐Shtrikman bounds (central curve)

Fig. 2. Illustration of the core‐shell model with cubic cells consisting of a crystalline core (grey) and a grain boundary of thickness t/2.

The presented model allows a single‐phase polycrys‐ culation as for one‐phase materials is carried out, taking talline material to be treated as quasi‐two‐phase, and the core phase as an average composite phase. due to the resemblance of the model geometry to the Numerical simulations coated spheres assemblage – the structure for which the In addition to the analytical modeling, also numerical Hashin‐Shtrikman bounds provide exact solutions ‐ the simulations were performed via the finite element me‐ lower Hashin‐Shtrikman bound is used for the calcula‐ thod (FEM), using a commercially available software tion of the effective thermal conductivity. In the case of package (COMSOL Multiphysics, COMSOL, Inc., USA). All two‐phase composites (e.g. the Al2O3‐ZrO2 ceramics), the the simulations in this work were run in the Heat Trans‐ estimate is calculated in two steps. Firstly, the effective fer Module under steady state conditions. In order to ob‐ thermal conductivity of the crystalline phase is calcu‐ tain the effective thermal conductivity, a temperature lated (via the sigmoidal average) and then the same cal‐ difference of 10 K was introduced on two opposite sides

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of the unit cubic domain, while all four other sides were randomly assigned. Examples of these random micro‐ under adiabatic boundary conditions. Then, heat flux in structures are shown in Fig. 3 for the compositions the normal direction to the cube sides was integrated A10Z90 – A50Z50. The value of thermal conductivity was and thermal conductivity was calculated. obtained as an arithmetic average of conductivities in the The first part of the numerical simulations was fo‐ three directions perpendicular to the sides of the cubic cused on the calculation of thermal conductivity in de‐ domain. This kind of microstructure is the so‐called pendence on phase composition. Simulations were run three‐dimensional random checkerboard, a type of SCM for compositions ranging from A10Z90 (i.e. 10 vol.% of structure, and can be assumed to be a good approxima‐ alumina, 90 vol.% zirconia) to A90Z10 with 10 vol.% tion of a two‐phase polycrystalline material with mono‐ steps. The microstructure consisted of 125 cubes to disperse grain size distribution. which the properties of either alumina or zirconia were

Fig. 3. Randomly generated microstructures used for numerical simulations in COMSOL Multiphysics; from left to right A10Z90, A20Z80, A30Z70, A40Z60 and A50Z50.

In the second part of the simulations, the grain size run, viz. for pure Al2O3 and ZrO2. In order to reduce the dependence of thermal conductivity was modeled. The computational demands, a model system containing only same geometrical model as for the analytical prediction one unit cell was used for calculations. In order to verify was used (core‐shell structure with t = 1 nm and grain that a single cubic cell model provides credible results, boundary thermal conductivity 1.1 W/mK) and simula‐ both the influence of number of unit cells and of mesh tions were run for grain sizes 1.5, 2, 5, 10, 20, 50, 100 density was tested for the case of 5 nm Al2O3 grains. and 200 nm. Only one‐phase material simulations were

Fig. 4. Domains containing 1, 8, 27, 64 and 125 unit cells and corresponding meshes used for numerical simulations in COMSOL Multiphysics.

Domains consisting of 1, 8, 27, 64 and 125 unit cells shown that the use of a single unit cell was an acceptable were used with approximately the same number of ele‐ approximation, as the perturbation was smaller com‐ ments per unit cell (see Fig. 4) and also domains with on‐ pared to the difference that came from the change of ly one unit cell, but with different mesh densities (from mesh density (see below). 1000 to 100000 elements, see Fig. 5). The results have

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Fig. 5. Meshes with density from 1000 to 100000 elements generated in COMSOL Multiphysics.

Results Beran bounds and that they are rather close to the sig‐ Fig. 6 shows the results of FEM calculations using the moidal average of Hashin‐Shtrikman bounds, indicating simple model of SCMs with cubic cells in random ar‐ an S‐shaped dependence on the zirconia content, as ex‐ rangement (3D random checkerboard). It is evident that pected. the numerical values lie between the upper and lower

Effective thermal conductivity [W/mK] 0 0 0.2 0.4 0.6 0.8 1

ZrO2 volume fraction [1]

Fig. 6. Effective thermal conductivity of Al2O3 – ZrO2 composite ceramics with random microstructure (cubic cell SCM) vs.

the volume fraction of ZrO2; upper and lower Beran bounds (dashed curves), sigmoidal average of the Hashin‐Shtrikman bounds (central curve) and data obtained from FEM calculations (full squares).

In [5], the sigmoidal average and Hashin‐Shtrikman Table 1. The influence of mesh density and number upper and lower bounds are compared with experimen‐ of cubic cells in one unit cubic domain on the effective tal data and simulation results published in the literature thermal conductivity calculated by FEM. [6‐8]. The comparison with literature data shows that experimental values lie predominantly between the low‐ Number of Number of Effective er Hashin‐Shtrikman bound and the sigmoidal average of cubic cells mesh elements thermal conduc‐ the Hashin‐Shtrikman bounds. (approx.) tivity [W/mK] As was mentioned above, before modeling the grain 1 1000 4.11 size dependence, the influence of mesh density and of the 1 2000 4.08 number of cubic cells in the unit cubic domain was 1 5000 4.11 checked in order to get a realistic estimate of possible nu‐ 1 10000 4.16 merical artifacts in the FEM modeling results. The results 1 100000 4.17 presented in Tab. 1 show that the thermal conductivity 8 8000 4.08 values varied by about 2% and that the influence of mesh 27 27100 4.08 density was slightly higher compared to the influence of 64 64100 4.09 the number of cells. The absolute values for the example 125 127900 4.10 with 5 nm grains varied from 4.08 to 4.17 W/mK.

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In Fig. 7 the grain size dependence of the effective good agreement with the analytical prediction. That thermal conductivity is presented both based on analyti‐ means that the modeling approach using the lower Ha‐ cal predictions (for alumina, zirconia and two common shin‐Shtrikman bound is well justified. The decrease in composite compositions, so‐called ZTA and ATZ compo‐ thermal conductivity is more significant for alumina‐rich sites) and numerical simulations (only for alumina and composites and starts to be significant for grains of ap‐ zirconia). Of course, with decreasing grain size the ther‐ prox. 100 – 200 nm and smaller. Comparison of analytical mal conductivity decreases in all cases (as expected) and prediction with experimental data from literature was approaches the more or less universal value of 1.1 provided in [5], and the analytical prediction provided a W/mK, the thermal conductivity of the grain boundary good approximation except for materials with very small phase (although the coarse‐grained materials have dif‐ grains (20‐40 nm), which had significantly lower thermal ferent thermal conductivities). Note that the numerical conductivity. simulations for alumina and zirconia are in surprisingly

5 Effective thermal conductivity [W/mK] 0 1 10 100 1000 10000 Grain size [nm]

Fig. 7. Grain size dependence of the effective thermal conductivity; data obtained from finite element method

calculations (full triangles for Al2O3 and empty squares for ZrO2) and analytical calculations: pure Al2O3

(solid bold curve), ZrO2 (solid thin curve), and two typical composites, ZTA (85 wt.% Al2O3 and

15 wt.% ZrO2 – dashed curve) and ATZ (20 wt.% Al2O3 and 80 wt.% ZrO2 – dotted curve)

3. CONCLUSION computational point of view. Both the analytical and In the presented work, both analytical and numerical numerical calculations provide theoretical values (pre‐ methods have been used for predicting the dependence dictions) of effective thermal conductivity for dense ce‐ of the thermal conductivity of Al2O3 – ZrO2 composite ce‐ ramics, and both approaches are suitable for macroscop‐ ramics both on composition and grain size. The analytical ically isotropic composites. Compared to each other, the approach is based on the rigorous bounds (in this case data are in a very good mutual agreement (see Figs. 6 the Hashin‐Shtrikman bounds) and their sigmoidal aver‐ and 7). However, compared to the scarce experimental age for the composition dependence and on the so‐ data published in the literature, it seems that the calcu‐ called phase‐mixture approach for the grain size depen‐ lated values are generally higher. This discrepancy can be dence. Numerical simulations were run using the COM‐ attributed to the fact that the calculations are made for SOL Multiphysics software, and results were obtained for fully dense and perfect materials, while the measure‐ the cases (model microstructures and geometries) ments were carried out on real samples, which may con‐ solved also by the analytical approach. It was shown that tain defects and imperfections, the effect of which is the the core‐shell geometrical model consisting of crystalline reduction of the effective thermal conductivity of the core and grain boundary phase can be used for numeri‐ material. It has to be emphasized that the two ap‐ cal simulations in the form of a single unit cubic cell, thus proaches presented here are applicable not only to Al2O3 making the calculations simple and economical from a – ZrO2 composite ceramics, but are of general use.

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References conia‐alumina composites, Ceramics International 1. TORQUATO, S.: Random Heterogeneous Materials: Mi‐ 2005, 31, 911–916. crostructure and Macroscopic Properties, New York, 5. PABST, W. and J. HOSTAŠA: Thermal conductivity of ce‐ NY: Springer, 2002. ramic nanocomposites – the phase mixture modeling 2. PABST, W. and E. GREGOROVÁ: New Developments in approach, Advances in Science and Technology 2010, Materials Science Research, Effective Thermal and 71, 68‐73. Thermoelastic Properties of Alumina, Zirconia and 6. BEGAND, S., T. OBERBACH and W. GLIEN: Material para‐ Alumina‐zirconia Composite Ceramics, pp. 77–137, meters in the system Al2O3‐ZrO2, Key Engineering Ma‐ New York, NY: Nova Science Publishers, 2007. terials 2007, 361‐363, 759–762. 3. PABST, W., E. GREGOROVÁ and J. HOSTAŠA: Phase Mixture 7. OBERBACH, T., S. BEGAND, W. GLIEN et al.: Investigation Models for the Thermal Conductivity of Nanofluids of aged dispersion ceramics by means of hip simula‐ and Nanocrystalline Solids, in Powders and Grains tor, Key Engineering Materials 2008, 361‐363, 771– 2009, Proceedings of the 6th International Confe‐ 774. rence on Micromechanics of Granular Media, eds. 8. IUGA, M. and F. RAETHER: FEM simulations of micro‐ M. Nakagawa a S. Luding, AIP Conference Proceed‐ structure effects on thermoelastic properties of sin‐ ings 1145, Melville, NY: American Institute of Physics, tered ceramics, Journal of the European Ceramic So‐ 2009 pp. 109–112. ciety 2007, 27, 511–516. 4. BANSAL, N. P. and D. ZHU: Thermal conductivity of zir‐

Al2O3-ZrO2 kompozituri keramikis Tbogamtarobis analitikuri da ricxviTi gaangariSeba i. hostaSa, v. pabsti minis da keramikis departamenti, qimiuri teqnologiis instituti, praRa, CexeTis respublika.

reziume: Tbogamtaroba keramikuli masalebis erT-erTi ZiriTadi Tvisebaa. gamoiyeneba, rogorc saizolacio, cecxlgamZle an eleqtronikaSi gamosayenebeli masala. mocemuli naSromis Temaa Al2O3-ZrO2 kompozituri keramikuli masalis Tbogamtarobis dadgena da gaangariSeba analitikuri da cifruli midgomebis gamoyenebiT. Tbogamtarobis damokidebuleba kompozitze da marcvlis zomaze gaTvaliswinebulia erT da orfaza kompozitebisTvis. pirvel nawilSi mocemulia mikromeqanikuri zRvris (haSin-Strikmanis zRvari) da marcvlis zomis fazuri Serevis midgomis safuZvelze kompozitze damokidebulebis analitikuri gadawyveta axali Sefardebis gamoyenebiT (saSualo sigmoiduri). am ukanasknelis dasamtkiceblad miRebulia marcvlis sazRvris modeli, rogorc 1 nm sisqis izolirebuli faza da Tbogamtaroba, romelic miaxloebulia minebis da amorfuli dieleqtrikebis TbogamtarobasTan anu tolia 1.1 W/mK. meore nawili aris Tbogamtarobis ricxviTi gamoTvlebi saboloo elementis meTodis mixedviT (COMSOL Multiphysics software), romelic gamoiyeneba modelis geometriasa da SemTxveviT warmoqmnil mikrostruqturebSi. gamoTvlebis orive meTodis Sedegebi Sedarebulia erTmaneTTan da eqsperimentul monacemebTan. mocemuli analitikuri da ricxobrivi midgomebi

SemuSavebulia ara marto Al2O3-ZrO2 sistemisTvis, aramed zogadad gamoiyeneba nebismieri izotropuli marcvlovani kompozituri masalisTvis.

sakvanZo sityvebi: Tixamiwa; beranis zRvari; kompoziti; bolo elementis meTodi; marcvlis zoma; haSin-Strikmanis zRvari; nanokristaluri keramika; Termogamtaroba; vineris zRvari; cirkoniumis orJangi.

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UDC 666. 1/2: 666. 3/7: 666. 4/5 SYNTHESIS OF SPECIAL MATERIALS ON THE BASIS OF MANGANESE BEARING RAW MATERIAL AND INVESTIGATION OF SOME THEIR PROPERTIES M. Shavlakadze, T. Cheishvili Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia E‐mail: [email protected] available manganese containing ores and slimes Resume: Experimental research was carried out (materials characterized with low solubility and low with the purpose of stating the possibility of receiving effectiveness). Thus, the production of such manganese manganese bearing materials usable as micro fertilizer. containing materials which ensure their using in On the basis of manganese dioxide, manganese ore and agriculture as micro fertilizers which should have to be manganese slag, the conditions of receiving the expressed in receiving micro fertilizers distinguished with materials in compositions of model and other mono and effective selective solubility and prolonged action binary composition composite materials, their solubility becomes very important. The receiving of these and other characteristic properties have been studied. materials became possible in composites made on the The carried out research makes the precondition for basis of manganese ore and slime using the methods creation of prolonged action inorganic and organic well known in ceramic technology. manganese containing new composition, for creation in perspective of materials usable as micro fertilizers. 2. THE BODY OF THE ARTICLE Experimental work comprising two directions has Key words: manganese ore; slag; dioxide; charge; been carried out. One of them considered the synthesis; solubility. establishment of the possibility of receiving new composition short (distinguished with good solubility) and long (distinguished with prolonged or low solubility 1. INTRODUCTION factor) acting materials with the view of solubility in soil. It is known that manganese containing compounds The purpose of researches made in the second direction are widely used in metallurgy (manganese alloys), silicate was to transform low solubility manganese oxide production (dyes, radiation resistive materials, etc.), compounds existing in manganese containing materials agriculture (micro fertilizers) and so on. Out of the (ore, slime) composition to solubility‐prone compound mentioned materials, the materials used as micro and generally, of “activation“ of such materials. The fertilizers can be separated, particularly artificial composition of materials used in experimental manganese chelate and sulfate (materials with high researches is given in Table 1. solubility in soil and short effectiveness) and easily

Chemical composition of manganese containing materials Name and Chemical composition, % No symbolic CaO+ MnO+ Losses at SiO2 Al2O3 MnSO4 Fe2O3 notation MgO MnO2 heating 1 Manganese ore (MR) 9.9 1.5 2.5 68.5 - 1.8 15.8 2 Manganese sulfate slime 45.9 4.9 0.31 28.5 4.1 0.2 16.6 (MS) 3 Manganese dioxide (M2) - - - 99.0 - - 1.0

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In order to determine the materials solubility composition of material to be received taking into capacity a 2% citric acid aqueous solution was taken as account the data given in reference literature [1, 2, 3]. test reagent, while the synthesis of materials was On the initial stage of research model, mainly binary realized in electric furnace, in air circulation conditions, composites with participation of manganese (IV) oxide in porcelain glazed pots (material synthesis up to 2000C) (main component of pyrolysic natural ores) and selected or in corundum pots (high temperature synthesis up to ingredients (organic or inorganic) have been prepared 10000C). The conditions of materials thermal synthesis and investigated. Different composition 9 composites was determined with consideration of the type and have been selected.

Charges of manganese containing materials, conditions of their synthesis and solubility indices

No Material’s Composition components, Conditions of synthesis Solubility index weight% losses (weight Manganese Second Time, hour Temp. 0C %) in test dioxide component reagent 1 M 100 - 3.0 300±20 1.6

2 MD 43.5 CaCO3 •MgCO3 3.0 800±20 23.6 56.5 3 MP 57.0 K 2CO3 3.0 800±20 36.5 45.0

H 3 BO3 4 MB 19.5 80.5 2.0 800±20 55.1

C6 H 8O7 •H 2O 5 MN 21.5 61.5 2.0 185±5 41.4

CHO224•2 HO 2 6 ML 38.5 60.0 2.0 185±5 11.5

NH 4 NO3 7 MC 40.0 70.5 2.0 185±5 89.5

H 3 BO3 8 B - 100 2.0 600±10 93.5

9 D - CaCO3 •MgCO3 2.0 110±10 11.2 100

The chosen composites allowed to receive inorganic particular as they contain manganese and also, nature manganite substances CaMnO3, MgMnO3 and potassium and magnesium very important for plants.

K2Mn2O3 (compositions 2 and 3), manganese (II) borate Especially important is the synthesis of manganese

Mn(BO2)2 (composition 4), also nitrate Mn(NO3)2 borate as of the material having mean solubility (65%) (composition 5). The compositions 5, 6, 7 (MN, ML and which does not contain any “ballast” and represents MC) presented in Table have been chosen with the micro fertilizer of practically 100% absorption. Very high purpose to receive manganese (II) nitrate, citrate and solubility is fixed for MN (Manganese nitrate) material oxalate distinguished with different solubility. received on the basis of MnO2 and NH4NO3. The results of the research presented in Table show Different values of solubility are characteristic to that manganese (IV) oxide solubility in test reagent is manganese organic compounds, particularly, those very low, which indicates ineffectiveness of purposeful indicated with indices ML and MC. Especially low direct using of manganese oxide and manganese oxide solubility is characteristic to manganese oxalate, containing materials. But, the solubility of the received manganese citrate is solved better. In both material, Mn materials differs from solubility of the initial components concentration is optimum (30‐38%) and is in absolute while according to solubility index they can be correlation with its “classic” composition presented in conventionally attributed to low (DM‐composition) and manganese sulfate [4]. medium (MP, MB) solubility materials. It should be mentioned that all three types of compositions are very

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With participation of MR and MS materials MSB and MRB have been composed, as well as charges of model M2B materials, in which the possibility of manganese borate receipt determined interrelation existing between the ingredients.

Fig. 1. Spectral curves of extracts obtained with treatment of MSB(1) and MRB(2) materials in 2% CA.

Composition of mono and binary charges and solubility of manganese containing materials treated at different temperatures

Effect of thermo treatment Charge Charge compositions, mass% in materials’ test reagent, (material) solubility, % index 0 0 0 MS MR MnO2 H3BO3 750 C 850 C 950 C MS 100 ------MR - 100 - - - - - MSB 87.5 - - 101.4 22.1 18.2 7.9 MRB - 84.8 - 101.4 38.0 17.3 10.2 M2B - - 50.9 101.4 53.7 34.4 11.9

For manganese borate compositions have been The effect of granulommetry (δ) of synthesized stated that temperature increase for all considered materials on solubility (∆G) in reagent has been materials decreased its solubility in reagent. determined and the kinetics of solubility process has been At the same time model M2B is characterized with studied for MRB and MSB compositions. The particular higher solubility than MRB and MSB materials differing effect of materials grain sizes for 0≤δ≤2 (mm) case has with complicated composition and manganese content been detected. The further growth of grain sizes has less which is proved with respective spectral researches. effect on solubility index of researched materials (Fig.2).

The results of changes of weight losses (∆G) received with tests are studied for 2‐24 hours (τ, h) interval and it has been stated that MSB material solubility in water is less effective than in 2% CA but in both cases solubility decrease is fixed in the whole interval of reagent action (Fig.3). It appeared that model M2B composition and initial material showed similarity to MR (ore) solubility and stability of losses is achieved after 4‐8 hours. In general, with the tendency to solubility materials can be 0 1 2 3 4 presented in series Mr→MRB→MSB→M2B. δav., mm The received results should be directly depended on the change of materials phase composition at thermal Fig. 2. The dependence of solubility (∆G) on material treatment which is proved with carried out differential‐ sizes (δav) in test reagents of MSB(1) and MRB(2) materials thermal and X‐ray phase researches.

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basis some regularities have been proved. In test reagent of mono materials the solubility determination condition are their composition and thermal development conditions. In binary compositions one more factor becomes determinative of the received materials properties – the second ingredient and chemical composition of the material received with synthesis. The solubility of materials is determined with their materials granulometry and time of reagent action.

References

Fig.3. Kinetic curves of solubility of M2B(∙), MR(X), MRB(∆) and 1. M. Khutsianidze, M.Mshvildadze, T.Cheishvili. Study of MSB( ) composition materials in water (a) and (b) in 2% CA. the products of interaction of manganese oxides and cirtic acid. Chemical journal of Georgia, v.6 No 2, 3. CONCLUSION 2006. (in Georgian) The received results enable to make solution that it is 2. Diagrams of silicate systems state. Reference book. possible to produce promising new composition First ed. Double systems. L. 1969. (in Russian). manganese containing inorganic and organic materials 3. Chemist’s reference book. V.II., L., Chimia. 1965. (in with the view of their using in practical means and as Russian). micro fertilizers. 4. Micro elements and micro fertilizers. www. In monocharges of manganese ore and manganese agromgroup.ry. 22/09/2008. sulfate slime and binary compositions made up on their

uak 666. 1/2: 666. 3/7: 666. 4/5 manganumSemcveli nedleulis safuZvelze specialuri masalebis sinTezi da maTi Tvisebebis Seswavla m. SavlayaZe, T. WeiSvili qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 69, saqarTvelo. reziume: Catarda eqsperimentuli kvleva, romelic miznad isaxavda mikrosasuqad gamoyenebadi manganumSemcveli masalebis miRebis SesaZleblobis dadgenas. manganumis dioqsidis, manganumis madnis da manganumSemcveli widis safuZvelze sinTeziT miRebuli, da Seswavlil iqna modeluri da sxva mono- da binaruli Sedgenilobis kompoziciebSi masalebis miRebis pirobebi, maTi xsnadoba da sxva maxasiaTebeli Tvisebebi. Catarebuli kvleva qmnis winapirobas manganumSemcveli axali Sedgenilobis prolonguri qmedebis, araorganuli da organuli saxis, perspeqtivaSi maTi mikrosasuqebad gamoyenebadi masalebis Sesaqmnelad. sakvanZo sityvebi: manganumis madani; wida; dioqsidi; kazmi; sinTezi; xsnadoba.

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UDC 09(54) SIMPLIFIED METHOD OF OLD KVEVRI (WINE VESSEL) DIGGING OUT FROM THE GROUND M. Tsintsadze, Kh. Tsikarishvili, R. Chagunava Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] occupied that deserted place, dug out those kvevris and Resume: The article discusses the simplified method took home” [2; p.128]. of old kvevris (wine vessel) digging out from ground In 1893 Iase Mordali, a noblemen, had written a spe‐ which has been developed by Georgian wine‐makers. cial petition to Prince Iovane about digging out of kvevris This method implied water saturation of soil layer adja‐ from marani (wine cellar). This petition reports that one cent to kvevri which caused the formation of expulsive of the bullying noblemen had invaded the wine cellar of force in soil layer relative to kvevri. As a result the vessel another nobleman and had tried to dig out kvevris. It was coming out of the ground all by itself without any seems that at digging two kvevris were broken and three force imposed. The expulsive force was also working kvevris had been taken intact. when wine‐jar was sealed with wet mortar. In order to From the petition of 1795 sent to King Erekle by avoid the mentioned phenomenon mortar was poured in priest Mate Kodalashvili it becomes known that from portion‐by‐portion and each portion was added to al‐ “deserted place” belonging to the priest the villagers of ready dried mortar. Matani and Akhmeta “had dug out kvevris” and in spite that “villagers of Bakhtriani told them not to take kvevris Key words: Kvevri (wine vessel), water, soil, digging as they had the owner” they did not change their mind out, sealing with mortar. and took away the dug out kvevris” [2; p.315]. The procedure of kvevri digging out of ground is

technically quite complicated and labour consuming 1. INTRODUCTION work. As a rule, around each kvevri an area far greater In viticulture of old Georgia, as is seen from a num‐ than its diameter was dug out in order that in the ber of old charters, quite widely was spread the practice process of digging the workers, little by little coming of repeated exploitation of already used wine vessels. down into the ground, had free area for uninterrupted The cause was that kvevris found at the sites of old work. At the same time, the process of digging needed ruined houses were of very high quality and extraction great caution as to avoid breaking or cracking of brittle work was economically more convenient than manufac‐ walls of the vessel. After getting down to the bottom turing of new wine jars. quite laborious and risky work was to be done which

meant kvevri’s extraction from the hole with ropes. 2. THE BODY OF THE ARTICLE The well known viticulturist L.Jorjadze had described The extraction of old kvevris and their transportation the method which simplifies the procedure of kvevri’s to a new place was widely spread practice in Georgia extraction and implied digging of ground on the whole since the ancient times. This is well seen from a docu‐ height on one side of the kvevri. After this, kvevri was ment of the 2nd half of the XIII century which reports leant on the dug side and the empty place left on the about one vizier: “He made to dig out churis (large bu‐ bottom of the hole was filled with a certain portion of ried wine‐jars), made his sister to take eight of them to soil. Then the kvevri was stood vertically on this raised Sachreteli. Two churis were left and were taken to Bna‐ heap and now the raised section was filled with soil. visi” [1; p.186]. Here we see that vizier had dug up ten Again kvevri was leant on the raised place and this churis from the ground, eight of them he sent to village process of kvevri leaning on one and the other side and Sachreteli and two ones to village Bnavisi. adding soil on both sides was continued [3; p.234]. At the end of the XVIII century we often come across Besides the described usual methods of kvevri ex‐ petitions containing complaints connected with willful traction, in practice there was a third method as well, extraction of old kvevris at devastated estates or usual which was written down in 1997 according to the narra‐ houses. For example, in 1791 priest Zakaria Chikladze in‐ tion of Sh.Bliadze, 77 years old informer from Chiatura. forms Prince Iulon in respect to one of the officials: “He

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According to the informer at first round hole was dug Water poured into the hole (4) dug around the upper out around the kvevri to the depth of the greatest di‐ part of kvevri (1) at draining into ground makes a “water ameter of this kvevri. Then, the empty place circum‐ jacket” around kvevri body, or more precisely, creates scribed with hole wall and upper part of kvevri was filled water saturated soil jacket (3). In such media expulsive with water. Water was added each time when the pre‐ force begins to act on the body of kvevri which after vious volume of water was absolutely drained out. After “water jacket” achieves a certain thickness becomes so as certain time, which depended on the type of soil, the much substantial that kvevri is pushed out on the surface kvevri began to rise on the ground surface without assis‐ of the ground. tance. Sometimes this simple method of kvevri extraction The mentioned phenomenon is visually demonstra‐ with water worked in nature, too. Particularly, in July of ted in Fig. 1. 2007, in the village Gavazi after heavy downpours the ground was so saturated with water that empty kvevris dug in in the open air began coming out of the ground by themselves. Another method of the action of expulsive force on kvevris was also known to Georgian wine‐makers. When for sealing, mortar was poured between the walls of dug out hole and the walls of the kvevri put into it the wine jars began upward motion. According to the statement of sealing masters “if mortar is poured momentarily it will tighten around the kvevri and will break or push up the wine jar“ [4; p.132], i.e. mortar in wet condition has the same affect on kvevri as the water saturated soil around the vessel. According to the information of the well known ethnographer L.Pruidze, in order to avoid this undesirable phenomenon Georgian masters elabo‐ Fig.1. Scheme of kvevri extraction with water rated the method of step‐by‐step sealing. 1. Kvevri, 2. Ground, 3. “Water jacket”, 4. hole

Fig. 2. Kvevris dug in in the open air

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Fig.3. Kvevri ready for sealing

In the process of sealing when wet mortar raised up tioned in Georgian life the development of a new me‐ to about 70 cm, mortar pouring was stopped until the thod which was simple and guaranteed safe dug out of poured mortar was absolutely dried and solidified. After kvevri, as well. this, a new portion of mixture was again poured in until achieving the measured height, was delayed for drying References and the process was continued until the end of sealing. 1. Block of Georgian historical documents. ”Mets‐ The mentioned methods which consider different ap‐ niereba”. Tbilisi. 1984. proaches to the same physical phenomenon indicate once 2. Texts of Georgian laws. v.VIII. “Metsmniereba”. more high professional level of Georgian winemakers. Tbilisi. 1985. 3. L.Jorjadze. Viticulture. Tbilisi. 1876. 3. CONCLUSION 4. L.Pruidze. Vine‐growing and wine‐making in Thus, the difficulty of old kvevris extracting proce‐ Georgia. I. Racha. Academy of Sciences of Geor‐ dure which required very large ground works had condi‐ gia. Tbilisi. 1974.

uak 09(54) miwidan Zveli qvevrebis amoRebis gamartivebuli wesi m. cincaZe, x. wiqariSvili, r. Cagunava qimiuri da biologiuri teqnologiebis departamenti. saqarTvelos teqnikuri universiteti, 0175, Tbilisi, kostavas 69, saqarTvelo. reziume: statiaSi ganxilulia Zveli qvevrebis miwidan amoRebis gamartivebuli wesi, romelic qarTvelma meRvineebma SeimuSaves. Ees wesi iTvaliswinebda qvevris garSemo mimde- bare miwis fenis wyliT gajerebas, rac am fenaSi qvevris mimarT amomgdebi Zalis gaCenas iwvevda. Sedegad WurWeli miwidan TviTneburad, yovelgvari Zalis datanebis gareSe amo- dioda. amomgdebi Zala qvevris Cakirvisas sveli duRabis pirobebSic iCenda Tavs. aRniSnu- li movlenis Tavidan asacileblad am duRabis Casxma wyvetilad mimdinareobda da Ti- Toeuli ulufa ukve gamomSral duRabs emateboda. sakvanZo sityvebi: qvevri; wyali; miwa; amoReba; Cakirva.

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UDC 536.45; 539.893 GRADIENTLY ANISOTROPIC CONDUCTING POLYMER COMPOSITES G. Basilaia, J. Aneli, L. Nadareishvili R.Dvali Institute of Machine Mechanics. 10, Mindeli Str. Tbilisi, 0186, Georgia. E‐mail: [email protected] To the graphite suspension the surface active Resume: The character of variation of the local substance was added and dispersed in the colloid mill electric resistance of sheet polymer composites on the during definite time. After this the water solution of basis of polyvinyl alcohol and graphite after orientation polyvinyl alcohol was prepared and intensively mixed. has been studied. It is established that this change The mixture was filtered and the film was formed on the essentially depends on both initial shape of the films and dryer table. on direction of their orientation. It is concluded that the The specific volumetric electric resistance of the films of gradiently anisotropic polymer composites may polymer films obtained with using of described above be used in electronics. method was changed in the interval 10‐50 kOhm.sm. The selection of such interval of the composite resistance was dictated by preliminary selection of conducting Key words: local electric resistance; polyvinyl alco‐ composites effectively reacted on the mechanical hol; graphite; gradiently anisotropic polymer. deformations. The experiments were carried out on the basis of 1. INTRODUCTION one and same electric conducting polymer composite It is well known that there are several methods for films with rectangle and trapezoidal shapes, the width of obtaining of materials with anisotropic properties which was no more than 0.2 mm. The deviation of the (copolymerization, polymer‐analogous transformation, resistance of any local region of the film was no more radiation –chemical modifications, etc.) [1,2]. At present than 10%. These films were fixed in special clamps, for obtaining of such structures one of the best methods placed to the heater and were stretched on 200‐300% is the orientation of polymer films in the definite with rate 50 cm/min at temperatures 100‐120oC. direction and environment conditions. It is known also Stretching was conducted for rectangle form sample that at stretching of thermoplastic polymers above glass along big side and for trapezoidal sample in parallel temperature the material in orientation state is formed. direction to bases (Fig.1 and 2). Polymer obtains the anisotropy of mono‐axis crystal symmetry. In this state the principal direction of macromolecules coincides with the direction of stretching. If the polymer filled with different dispersive fillers among which may be the electric conductive materials (metal powders, graphite, carbon black) the particles of the latters interacting with macromolecules N a b from chaotic state transform to orientation one, too. Fig.1. Rectangle (A) and trapezoidal (B) shape films before (top) The change of polymer microstructure in this case and after (bottom) stretching. Dashed line indicates the equiresistent entirely define the material properties [3,4]. regions (numbers in megaohms) In the presented work the character of change of electric conductivity of composites in view of films based on polyvinyl alcohol and graphite at their gradiental stretching has been investigated.

2. THE BODY OF THE ARTICLE The films were prepared using the following techno‐ Fig.2. The scheme of orientation of trapezoidal shape film. A – logy: before stretching, B –after stretching

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After strtching of the deformed films local resistances described by increasing of degree of reservation of were measured. First of all, it was necessary to mark the electric conductive channels [4]. film with square grid. In our case the length of square side was equal to 5 mm. The local resistances were 16 measured by using of twin needles after touching them 14 to the film. The measuring of resistance of elementary 12 cages were performed several times and then the 10 average significances of resistances were calculated. 8 max R 6 Results and discussion 4 2

0 As a result of measuring of local resistances of -2 oriented rectangle shape samples it was established 0246 dl/l that maximum change of this parameter was noticed o along symmetry axes taken along the longest side of the Fig.4. Dependence of local resistances on the stretching degree rectangle. This change has an extreme character (the maximum is at the central part of the film) and its full shape has Gaussian form. Fig.3 shows that the amount of maximum of the local resistances depends on the value of stretching. This dependence is near to exponent (Fig.4). This result is in good agreement with the known conception on the mechanism of conductivity of conductive polymer composites [3]. The analogical character has the same dependence for films stretched in rectangle direction having the analogical character of the same dependence, although this dependence is somewhat weaker.

240

200 3

160

120 2 R, kOhm 80

40 1

-6 -4 -2 0 2 4 6 d, cm

Fig. 3. Dependence of local resistances on the value of stretching. 1‐ 150%, 2‐200%, 3‐ 300% Fig.5. Dependences of local resistances on the film coordinates It was interesting to establish the character of the in the stretched ( 200%) trapezoidal shape samples: top – along perpendicular to stretching direction; bottom – a long stretching above considered functional dependences on the direction ( for stripes placed on one side from central strip. The concentration of powder electric conductive particles. numbers on the curves indicate the numbers of stripes in Fig.4 shows that the increase of filler concentration leads perpendicular (top) and parallel (bottom) to stretching direction to decreasing of resistance change both in parallel and in perpendicular directions. This phenomenon may be

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The geometry of distribution of local resistances in desirable anisotropy of electric conductance. The case of trapezoidal shape films is more complex. Its perspective is in application of above described materials analysis demands more scrupulous study, although in this for creation of the so called printed schemes. In case it is possible to describe definite lows of this problem. electronics these films will be useful for preparing of The following series was fulfilled on the trapezium of some functional micro‐schemes. the same shape, but with one difference – only small base and nearest to it region was stretched. Here was References created the mechanical stretch gradient in perpendicular 1. Polymers and polymeric materials for fiber and gra‐ to base direction (Fig.5). This gradient was increased dient optics / VSP (Utrecht‐Boston‐Köln‐Tokyo), from zero at big base and was ended at more stressed 2002 (With N.Lekishvili, L. Nadareishvili, et al.), small base with maximum. 230 p. Here it is interesting that if the shape of the clamps is 2. L. Nadareishvili et al. GB‐optics – a new direction of linear the dependence of stress (or deformation) in gradient optics. J.Appl.Pol.Sci.2004,v.91,489‐493. perpendicular to bases direction is hyperbolic and vice 3. J. Aneli, L. Khananashvil, G. Zaikov. Structuring and versa, if the clamps shape is hyperbolic, this dependence conductivity of polymer composites. Nova Sci. Publ. has linear character. At this time this phenomenon is yet N.–Y. 1998, 326 p. unknown. Investigation of this problem will be conducted 4. J. Aneli, L. Khananashvil, G. Zaikov. Effects of mecha‐ with using of modern methods of structure analysis. nical deformations on structurization and electric conductivity of polymer composites. J.Appl.Pol.Sci. 3. CONCLUSION 1999, v.74,p.601‐621. The experiments described above open the perspectives in the field of creation of the films with

uak 536.45; 539.893 anizotropuli gamtari polimeruli kompozitebi g. basilaia, j. aneli, l. nadareiSvili r. dvalis manqanaTa meqanikis instituti, mindelis 10, Tbilisi 0186, saqarTvelo.

reziume: Seswavlilia polivinilqloridisa da grafitis safuZvelze miRebuli polimeruli kompoziciuri masalebisgan damzadebuli firisebri eleqtrogamtari masalebis lokaluri eleqtruli winaRobebis cvlileba firebis orientirebis Semdeg. dadgenilia, rom es cvlilebebi arsebiTad damokidebulia rogorc firis sawyis formaze, ise misi gaWimvis mimarTulebaze. miRebuli Sedegebis bazaze gakeTebulia daskvna gradientulad orientirebuli eleqtrogamtari firebis eleqtronikaSi gamoyenebis Sesaxeb.E

sakvanZo sityvebi: lokaluri eleqtruli winaRoba; polivinilqloridi; grafiti; firi; gradientulad orientirebuli.

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UDC 666.12 STUDY OF ACID MAGMATIC ROCKS OF SOUTH‐EAST GEORGIA FOR THE PURPUSE OF USE IN GLASS AND CERAMICS PRODUCTION N. Kamushadze, L. Gabunia, E. Shapakidze, I. Gejadze, R. Kvatashidze, M. Khutsianidze Caucasian Alexander Tvalchrelidze Institite of Mineral Resources, 85, Paliashvili st., Tbilisi, 0162, Georgia

E‐mail: [email protected] hyaloandesites of Arsiani Ridge, which are characterized Resume: The work is dedicated to the study of pos‐ by unified content of SiO2, Al2O3 and R2O [1]. sibility of use of South‐East Georgian acid magmatic rock According to chemical composition there is high con‐ as a basic raw material in the production of finishing tent of SiO2 and Al2O3 in the mentioned rocks; alkaline glass slabs with colored surface and ceramic slabs for ex‐ metals are represented in the form of Na and K oxides, ternal and internal finishing. besides, in the case of metasomatites and rhyolites, in‐ creased quantity of potassium oxides – up to 6.5‐8% is Key words: acid magmatic rocks; finishing glass noted. Quartz‐adular metasomatites are characterized slabs with colored surface; ceramic slabs for external and by the content of barium sulphate up to 4‐5%. As for fer‐ internal finishing. ric oxides, their content varies within 1.2‐2%, unlike hya‐ lo‐andesite, where Fe2O3 reaches up to 4%. Calcium and 1. INTRODUCTION Magnesium oxides are represented in small quantities. Georgia experiences deficit of high‐quality raw mate‐ Chemical compositions of the investigated rocks are rials intended for silicate production. In such situation, for provided in the Table 1. the purpose of extension of the raw material base, mining It has been established by mineralogical‐petrographic prospect of complex material, by means of which several research, that quartz‐adular metasomatites are repre‐ components will be introduced in silica blends simulta‐ sented by biotite, rarely – dense, metasomatically mod‐ neously, becomes very topical. It will lead to simplification ified fragmented tuffs of hornblende‐biotite rhyolite of silica blend and the technology of its preparation. composition. Rhyolites have massive structure. Their basic mass is of 2. THE BODY OF THE ARTICLE felsite, microlite or fluid nature; it is structured by quartz For this purpose, acid magmatic rocks of South‐East and feldspar crystals and quartzified volcanic glass; por‐ Georgia were chosen, in particular, in the form of quartz‐ phyry extracts are represented by quartz and feldspar. adular metasomatites, trachyte‐rhyolites, ignimbrites of Hornblende crystals, also plagioclase porphyry extracts, Mushevani location, rhyolites of Kochuli location and substituted by albite or quartz, are also encountered.

Table 1 Chemical compositions of the investigated rocks 3 3 2 5 2 3 O O O O

The name 2 O 2 2 2 2 ture SO K CaO BaO SiO P TiO MnO MgO

of rocks Na Al Fe Mois- L.O.I.

Quartz- adular me- 0.49 1.32 78.7 0.22 7.80 1.75 0.10 0.11 0.40 1.46 0.30 6.60 0.03 1.77 tasomatite

Ignimbrite 2.15 3.20 72.90 0.15 12.50 1.26 0.10 0.70 1.71 _ 2.80 2.50 0.03 _

Trachyte- 1.24 3.20 66.30 0.24 16.30 1.85 0.10 3.22 1.12 _ 5.00 1.10 0.12 0.01 rhyolite

Rhyolite 1.60 1.14 74.20 0.17 10.50 1.60 0.10 0.54 0.39 _ 0.90 7.80 0.06 _

Hyalo- 0.20 0.12 63.21 0.80 17.60 3.76 0.20 5.40 1.73 _ 4.80 1.90 0.30 _ andesite

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Ignimbrites are represented by microfelsitic, albitized and the superficial film is crystallized at maximum level basic mass, where metamorphosed plagioclase crystals and obtains pale‐brown crust. are well seen. Quartz phenocrystals are scattered in it, The dependence of linear expansion of glasses on rocks are mineralized irregularly, which is mainly temperature was studied for the determination of the represented in the form of fine‐dispersed ore mineral. temperature of burning (Fig. 1). Hyaloandesite is andesitic, volcanic erupted rock of hyalopilitic texture, where the formations of micropor‐ phyric plagioclase and pyroxene are encountered in very small quantities. Basic mass is crypto‐crystalline, is com‐ posed of glassy bodies with oriented microlites of pla‐ gioclase. As a result of provided researches, the possibility of use of the above mentioned rocks as a base material for obtaining of construction glass, as well as ceramic finish‐ ing slabs, has been established. The research was conducted for the purpose of ob‐ taining of finishing glass slabs with colored surface from the investigated raw minerals. Fig. 1. The temperature curves of linear expansion According to traditional methodologies, the use of scarce and expensive coloring matters – Cd, Se, Cu, etc. For the purpose of study of thermal expansion of is necessary. This circumstance, as well as complex tech‐ glasses, the temperature of their burning was deter‐ nology of production hampers mass introduction of co‐ mined within 580‐640°C. lored glass materials in construction. Against such back‐ Rhyolite of Kochulo location and ignimbrite of Mu‐ ground, development of cheap and available composi‐ shevani location were selected as basic raw materials for tions and simple technologies is very important and it the use in ceramic production. was done during the presented work. Due to low plasticity of the mentioned raw material, for In the developed optimal composition, on the basis of the purpose of improvement of technological properties of hyaloandesite, rhyolite and metasomatite, selection of the ceramic mass, the raw material was corrected by the addi‐ required proportion among oxides ensures formation of tion of plastic clay, in this case – local Metekhi clay. On the claret red‐brownish film on the surface of glass in the basis of investigated raw material and plastic clay the two‐ process of its free forming. In particular, certain amount of component blends were made, where the proportion of rocks and clays was 70% / 30%, correspondingly. oxides and hematite – Fe2O3 in its compositions (CaO+MgO) facilitates the migration of three‐valent iron Forming of the samples was done according to plastic ions to the glass surface, which takes the form of colored method. Burning of the formed slabs was carried out in film after cooling, whereas the glass in volume is black. electric furnace at temperatures 1000, 1050, 1100 and As a result of physical‐chemical researches for ex‐ 1150 °C; duration of burning – 7 hours at maximum tem‐ planation of superficial coloring mechanism, it was de‐ perature with 1 hr delay. tected that in the volume it represents black, transpa‐ For the determination of ceramic properties of expe‐ rent glass; its superficial colored film of 0.3‐0.5 mcm rimental blends, fire‐related and general shrinkage, wa‐ thickness is also glassy and is colored by ferric oxides, ter absorption, porosity and average density were de‐ where the intense spreading of spinel minerals of termined. The results are provided in Table 2. Optimal temperature of burning for internal wall fi‐ Fe(Fe,Al)2O4 composition is seen in the form of germ sub‐microscopic crystals, the size of which doesn’t ex‐ nishing slabs made 1050°C and for floor slabs – 1150°C. ceed 0.5 mcm. On the basis of study of physical‐mechanical charac‐ In the case of thermal processing of glass within the teristics of the samples it was established that the ob‐ range of 700–1000°C, the color and intensity of glossi‐ tained characteristics completely meet the requirements ness of the surface doesn’t change, while at 1050‐1100°C of standards for internal wall finishing slabs, as well as, the phase composition of the crystalline film changes for floor ceramic slabs.

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Table 2 Ceramic and physical‐mechanical properties of experimental blends Tempera- Shrinkage ,% Water ab- Average Basic raw ture of Porosity, Air shrinkage, Flexural sorption, density, material burning, fire- 3 % % strength , Mpa general kg/m °C related % 1000 0.4 4.4 17.0 1755 29.2 1050 1.0 5.0 15.0 1764 26.5 Rhyolite 1100 1.5 5.5 10.1 1680 17.9 1150 3.0 7.0 4.0 2028 8.3 3.8 21.8 1000 0.8 6.8 17.3 1704 29.4 1050 1.1 7.1 15.0 1740 26.0 Ignimbrite 1100 1.9 7.9 9.2 1859 17.1 1150 3.0 9.0 3.5 2020 7.2 5.2 33.5

By low‐melting standard solid glazing of the slabs of both construction glass and ceramic slabs was estab‐ burnt at the temperature 1150°C and their further burn‐ lished. ing at the temperature 940 °C, well‐burnt slabs were ob‐ tained without deformation and cracks. References The study of characteristics of the obtained samples 1. L. Gabunia, G. Nadareishvili, J. Gejadze, E. Shapakidze, showed, that water absorption of the slabs is within 3,2‐ O. Machavariani, M. Tkemaladze, S. Kavtaradze. 4,0%, abrasion resistance makes 0,05‐0,07 g/cm2, which OVERBURDEN ROCKS OF THE DAVID GAREJI‐ completely meets the standard requirements for floor MUSHEVANY DEPOSIT, AS RAW MATERIALS FOR THE slabs [2, 3]. GLASS INDUSTRY OF GEORGIA. ‐ The 2nd International Scientific Conference of Ceramic Association. Tbilisi, 3. CONCLUSION 2009, p. 153‐154. 2. GOSI 6141‐91. Glazed ceramic tiles for lining of the Thus, on the basis of the performed research the sui‐ walls. Specifications. tability of the investigated rocks for using in production 3. GOST 6787‐2001. CERAMIC FLOOR TILES. Specifica‐ tions.

uak 666.12 samxreT-aRmosavleT saqarTvelos mJave magmuri qanebis Seswavla minisa da keramikis warmoebaSi gamoyenebis mizniT n. qamuSaZe, l. gabunia, e. SafaqiZe, i. gejaZe, r. kvataSiZe, g. enuqiZe, m. xucianiZe kavkasiis aleqsandre TvalWreliZis mineraluri nedleulis instituti, faliaSvilis 85, Tbilisi, 0162, saqarTvelo. reziume: samuSao eZRvneba samxreT-aRmosavleT saqarTvelos mJave magmuri qanebis ZiriTad nedleulad gamoyenebis SesaZleblobis Seswavlas minis feradzedapiriani mosapirkeTebeli filebis da Siga da gare mopirkeTebis keramikuli filebis warmoebaSi. sakvanZo sityvebi: mJave magmuri qanebi; minis feradzedapiriani mosapirkeTebeli filebi; keramikuli filebi Siga da gare mopirkeTebisaTvis.

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UDC 666.293.52 INVESTIGATION AND DEVELOPMENT OF ONE‐COAT GLASS ENAMELS WITH BEST ADHERENCE PROPERTIES N. Zeikidze, I. Berdzenishvili Department of Chemical and Biological Technology, Georgian Technical University. 69, Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] However, implementation of a single‐layer ename‐ Resume: The paper presents the results of investiga‐ ling technology requires specialized glass enamel frits tion and development of one‐coat zirconium‐strontium with a set of physical and mechanical properties to en‐ chemically resistant enamels, created for the protection of sure performance of pipelines in corrosive environ‐ pipes, working in corrosion‐active medium. It is shown ments (transportation of stratified water‐flooded oil that coatings adherence strength depends on the content with particles of sand, gypsum, clay). Corrosion of of complex adherence activators in them. The effect of pipelines under the influence of such media usually melts on a steel substrate increases at the content Со2O3 happens in 1–1,5 years after their commissioning. and СuO up to 1,8 weight %. Upgraded without fluorine and nickel one‐coat enamels of dark color meet the re‐ 2. THE BODY OF THE ARTICLE quirements of standards of enamel steel pipes. These Taking into consideration the indubitable economic enamels are recommended for testing on pipelines. prospects of direct‐on enameling of pipes, the objec‐ tive of our work was the development of compositions Key words: one‐coat enamels, direct‐on enameling, of special low‐melting one‐layer coatings. pipes, corrosion‐active medium, acid resistance, adhe‐ Besides, for compliance with European Standards, rence strength. it was essential to solve the problem of reducing the content of harmful fluorine and hard‐to‐get nickel 1. INTRODUCTION oxide, which, along with cobalt oxide, is one of the ba‐ Creating East‐West energy corridor, trans‐Caspian sic oxides of adhesion. Among expensive components and trans‐Caucasus oil and gas pipeline systems crossing of chemically resistant low‐melting coatings is lithium Georgia, raise issues of safe transportation of oil and gas carbonate, the cost of which makes up to 8‐16% of resources to world markets in a number of important the total cost of all raw materials of the blend. At the national objectives. Over the past decade the life of same time it wants to reduce the firing temperature pipes in almost all spheres of their application is de‐ and to improve the adhesion strength to steel. creased, on the one hand due to a sharp decrease in the Creation of new coatings that meet these require‐ corrosion resistance of metal, but on the other – due to ments will save much money, as the volume of use of increasing corrosive environments in which the pipes such enamels are enormous. are operating. Therefore, the exploitation of oil pipelines As a result of investigation performed we devel‐ without adequate protection is excluded [1‐6]. oped a series of experimental compositions of fluo‐ Traditionally used enameled pipes allow increasing rine‐free zirconium‐strontium enamel frits containing significantly the service life of pipelines, though their a complex of cobalt and copper oxides (0,5 – 0,8% and cost approaches the cost of stainless steel pipes. The 0,6 – 1,3%, respectively) as an adherence activator, high cost of enameled pipes is conditioned by the use which intensely imparted a blue color to the enamels. of technology of multilayer enameling, which is ac‐ The chemical composition of the developed frits of complished by the following scheme: metal‐primer‐ brand SL is as follows (wt.%): SiO2 44.2 – 51.8; enamel (2 layers‐2 firings) [4‐6]. ∑(ZrO2+TiO2) 6,5 – 9,0; B2O3 6,2 – 9,1; Al2O3 2,5 – 4,0;

Using of the technology of direct‐on enameling al‐ Co2O3 0,5 – 0,8; ∑(SrO+CaO+MgO) 9,3 – 13,9; CuO 0,6 lows solving the problems of manufacture of competi‐ – 1,3; Na2O 17,4 – 19,2; K2O 1,0 – 2,0 [7]. tive high‐quality products and making the production Glass frits were smelted at 1250‐13000C in weak process much simpler at the expense of reduction of the acid atmosphere in an electric silite furnace; digesting number of coating layers and firing cycles and, conse‐ time – 60‐90 minutes. The granulation of melts was quently, of the reduction of production costs [4, 6]. performed in water.

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The results of the X‐ray phase analysis of the blend X‐ray pattern shows the presence of quartz and sili‐ composition after heat treatment at 5000C, 7000C, 9000C cate zirconium crystals. and 11500C are given in Table 1. The synthesis of enamels was performed by the Table 1 slip‐firing technology on steel 9XГС sample pipes with Crystalline phases of the product of blend heating external diameter of 80‐426 mm, wall thickness of 2‐ Temperature, °С Phase composition after heat 10 mm and length of up to 2,6 m. treatment The enamels of brand SL with optimal firing tem‐ 500 Na Ca(CO ) , NaBO , SrCO , 2 3 2 2 3 perature of 760‐7700C are easy to manufacture; they Al2O3, ZrSiO4, SiO2 form in wide temperature range (800) in 15‐20 minutes 700 SrCO3 , Al2O3, ZrSiO4, SiO2 900 Na2CaSiO4, SrCO3, (Fig. 2). The firing of enamels was carried out by induc‐

Сa(Mg,Al)[(Si,Al)2O6], γ‐Na2Si2O5, tive method. ZrSiO4, SiO2 1150 ZrSiO4, SiO2 1300 −

The intensity of the processes of silicate and glass for‐ mation due to the formation is of multi‐component eutec‐ tics; Most refractory compounds (SiO2, ZrSiO4) in the tem‐ perature range 1150‐1300° C dissolved with the formation of a fully amorphous mass. Fig. 1 shows the X‐ray results of the charge mixture obtained at 1150° C.

Fig. 2. Sample pipes with two‐surface coating

The slip was prepared by milling of the frit in a ball mill with adding of 5% clay, 0.75% electrolytes and a fil‐

ler (marshallite (SiO2) and others) in the amount of 18 %. Such a composition of the slip allowed increasing the ac‐ id resistance of enamels by 35‐40% and expanding the 0 firing temperature range up to 120 (Fig. 3). Fig. 1. X‐ray investigation of crystalline phases of charge SL‐3

at 1150° C S − SiO2, Z − ZrSiO4

120 100 80 60 acid resistance,% 40 20 firing temperature 0 range

Fig. 3. Dependence of acid resistance and firing temperature range of glass covers on filler content

152

The results of complex tests of steel samples coated with single‐layer coatings 15 SL‐3 and 18 SL‐3 for their com‐ pliance with the specifications are presented in Table 2. Table 2 Parameters of composite glass coatings of brand SL Impact resis‐ Thick‐ Acid resis‐ Alkali resis‐ Compre‐ Heat resis‐ Wear, Brand tance, ness of tance, tance, ssive tance, DIN DIN of the GOST the ISО 2743 ISО 2745 strength 51167 51152 coating 3‐17‐48‐98 coating mg/cm2 mg/cm2 MPa °С J mg/m2 µm 15 SL‐3 0,14 0,21 1500 230 5,1 0,8 450 18 SL‐3 0,12 0,32 1600 250 5,6 0,7 450

Note: 15 SL‐3 and 18SL‐3 are the coatings with addition of 15% and 18% marshallite, respectively, to the milled grit. (based on frit SL‐3) were characterized by best adhe‐ The developed direct‐on enamels provide good as‐ rence strength (1‐2 grades) to the substrate. They con‐ similation of mineral fillers in the amount of 15‐18%. tain the minimum quantity of expensive adherence

This makes possible applying a 450µm layer with high promoter components (Co2O3 + CuO) up to 1.8 wt.%, degree of smoothness and luster to steel items. increasing the reaction activity of melts on a steel. The The adherence strength, which is the most impor‐ coatings based on frits SL‐1 and SL‐4 with high content tant property of direct‐on enamels, was estimated by of magnesium and boron were not satisfactory and impact testing in accordance with European Norms EN their estimation made 4‐5 grades, i.e. the area of 10209 [4]. Fig. 4 shows the exterior view of two ena‐ enamel spalling was equal to 60‐70%. meled samples after the impact test. From the expe‐ rimental compositions, coatings 15 SL‐3 and 18 SL‐3

15 SL‐3 15 SL‐4

Fig. 4. The exterior view of enamelled samples after impact tests

The comprehensive tests also involved soaking of the • the appearance of coatings remained unchanged in all best samples with coatings 15 SL-3 and 18SL-3 in crude media; oil for 1000 hours and, in accordance with techniques • the adherence strength, determined by the method of NACE TM 0177-96 and TM 0284-96, in the medium impact load, remained at the level of initial values; the character of spalling did not change; containing 5% solution of NaCl (GOST 4233) +0,5% so- • the characteristics of coatings satisfied the specifica- lution of CH3COOH (GOST 19814) and saturation with tions; hydrogen sulfide (pH ≤3,5; T=297K; testing time - 96 • the smooth vitreous surface excluded the formation of hours). In the result of tests, it was established that: protuberances.

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3. CONCLUSION 2. E. Proskurin. Protective coatings. Quality and ser‐ Thus, the obtained results show possibility of syn‐ vice life of pipes. National Metallurgy. 2003, #5, p. thesis of fluorine‐free competitive one‐coat glass 69‐78. enamels with a minimum quantity of expensive adhe‐ 3. V.I. Shkandratov, S. Kim. Anticorrosive protection. Oil rence activators Co2O3 and CuO. Direct‐on enamels and Gas Vertical, 2006, # 10, p. 158‐162. represent new environment‐friendly long‐lasting coat‐ 4. Technology of Enamels and Protective Coatings. Eds. ing systems which make it possible to prevent corro‐ L.L. Bragina and A.P. Zubekhin. – Kharkov: KPI , 2003. – sive destruction of inside and outside surfaces of oil 484p. and gas pipelines, oil product pipelines and heat pipe‐ 5. I. Berdzenishvili. Protective glass coatings for che‐ lines. All the above mentioned properties of glass mical equipment, pipes and pipelines. Tbilisi. Geor‐ enamels as well as their low cost allow to consider that gian Technical University, 2008, – 150p. their application to pipelines will be efficient and eco‐ 6. Theory, practice and prospects of the use of enam‐ nomically justified. elled pipes. Proceedings of the Conference. –

Penza: House of Knowledge, 1999, p.3‐24. References 7. I. Berdzenishvili. A Frit for direct‐on enamel coat‐ 1. V. Shubin, Yu.A. Ryumin. Reliability of equipment ing. Georgian Patent No. P 4765. Invention Bulletin, of chemical and oil‐refining industries. Moscow. 2009, 08, 25, #16. Chemistry, 2006. – 359 p.

uak 666.293.52 maRali adheziuri Tvisebebis mqone erTSriani minasafarebis SemuSaveba da kvleva n. zeikiZe, i. berZeniSvili qimiuri da biologiuri teqnologiis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, kostavas 69, saqarTvelo.

reziume: milebis koroziisagan dasacavad SemuSavebulia da gamokvleuli erTSriani ufToro qimiurad mdgradi minanqrebi, romlebic SeWidulobis aqtivatorTa minimalur raodenobas Seicavs. naCvenebia, rom minanqris ფოლადის სუბსტრატTan maqsimaluri SeWidu- loba aRiniSneba Со2O3 da СuO Semcvelobisas 1,8 წონ. %-მდე. ugrunto safarebis kompleqsuri gamocda dadebiTi SedegebiT dasrulda. konkurentunariani muqi feris minanqrebi Ta- visi fizikur-qimiuri da teqnologiuri maxasiaTeblebiT akmayofilebs moqmed standartebs. minanqrebi rekomendebulia milsadenebze gamosacdelad. sakvanZo sityvebi: erTSriani minasafari; milebi; koroziulad aqtiuri garemo; mJavemedego- ba; Sewebebis simtkice.

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EFFECT OF PYROPHİLLİTE ON FIRING BEHAVIOUR OF MONOPOROSA WALL TILE BODIES Özgür Cengiz*, Alpagut Kara** *Department of Material Science and Engineering, Anadolu University, Eskisehir, Turkey; **Ceramic Research Centre, Eskişehir, Turkey

a double beam non‐contact optical dilatometer (ODHT). Resume: In the production of ceramic wall tiles, fast The thermal properties were characterised by TG‐DTA. firing process requires a careful attention with regard to The phase and microstructural analyses were carried out the selection of raw materials. The aim of this study was by XRD and SEM, respectively. The results showed that to determine the effects of pyrophillite on fast firing be‐ an appropriate amount of pyrophillite has the potential haviour of large size monoporosa tiles by removing car‐ to give improved technological properties under fast fir‐ bonates and/or lowering decomposition temperature. In ing conditions so as to achieve thin wall tiles. order to achieve this, several body formulations contain‐ ing different amounts of pyrophillite were prepared and Key words: Wall Tile; Fast Firing; Pyrophillite; thin fired under laboratory conditions. The sintering beha‐ wall tile. viour of the representative bodies were evaluated using

pirofilitis gavlena monoporozas kedlis filebis gamowvis xasiaTze o. cengizi*, a. kara** *masalaTamcodneobis da sainJinro departamenti, anadolus universiteti, eskisehiri, TurqeTi; **keramikis kvleviTi centri, eskiseri, TurqeTi. reziume: keramikuli sakedle filebis damzadebisas gansakuTrebuli yuradReba unda mieqces nedleulis SerCevas swrafi gamowvis procesSi. mocemuli kvlevis mizania gani- sazRvros pirofilitis zemoqmedeba didi zomis monoporozas filebis swrafi gamowvis xasiaTze karbonatis moSorebiT da/an daSlis temperaturis SemcirebiT. amis miRwevis mizniT momzadda ramdenime ZiriTadi formula sxvadasxva raodenobis porfiritis Sem- cvelobiT da maTi gamowva Catarda laboratoriul pirobebSi. warmodgenili Sedgeni- lobis gamowvis xasiaTis gansazRvra moxda or-sxiviani ukontaqto optikuri dilato- metris gamoyenebiT (ODHT). Termuli Tvisebebi daxasiaTebulia NG-DTA-s meSveobiT. fazuri da mikrostruqturuli analizi Catarda, Sesabamisad, XRD da SEM-ze. Sedegebma gviC- vena, rom porofilitis saTanado raodenobis gamoyenebisas SesaZlebelia swrafi gamowvis pirobebSi miviRoT Txeli sakedle filebis damzadebis gaumjobesebuli teqnologiebi. sakvanZo sityvebi: sakedle fila; swrafi gamowva; pirofiliti; Txeli sakedle fila.

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UDC 615.1(075.8) DEVELOPMENT OF COSMETIC COMPOSITIONS CONTAINING KAOLINE, BENTONITE AND PELOID D. Jincharadze, N. Bokuchava Department of Chemical and Biological Technology, Georgian Technical University, Tbilisi, 0175, Kostava str. 69

E‐mail: [email protected] In the given report we continue this theme, having add‐ Resume: The formulas of various cosmetic composi‐ ed usage of curative mud. Besides, by present time we tions – shampoos, tooth‐pastes, cream‐masks are devel‐ had already developed compositions of cosmetic prod‐ oped, where kaoline, bentonite and peloid replace tradi‐ ucts containing clays and peloid. tional chemical components and besides having washing, Let's notice also, that in literature the new term – softening, jelling, foaming and tonic functions, bring also “cosmeceutics”, formed of words cosmetics and phar‐ their specific curative and prophylactic properties. At the maceutics becomes adopted. This term implies cosmet‐ same time similar properties are attached to product by ics with curative and prophylactic properties. As it fol‐ extracts of herbs and curative mineral waters. This lows from the title of the project the receipt of exactly enables to call the developed compositions – cosmeceu‐ such cosmetic products is the objective of our work tic products. where clays and peloids are not on the last place.

2. THE BODY OF THE ARTICLE Key words: kaolin; bentonite; peloid; mud; clay; The use of clays and peloids in curative and prophy‐ cosmeceutic; base; active component; recipe; formula. lactic purposes is widely known, proved and practically widely spread. In a sense, this is not an innovation in 1. INTRODUCTION cosmetology, either. The specificity of our work is re‐ Within the project “Development of compositions placement of synthetic chemical components in cosmetic and creation of samples of curative and prophylactic compositions with natural materials without loosing cosmetic production on the basis of natural resources of their corresponding functions – washing, softening, jel‐ Georgia” our group is conducting experimental research ling, foaming, tonic and remedial functions, etc. Clays and creates receipts of cosmetic creams, shampoos, and peloids should in more or less degree replace surfac‐ balms, lotions, tooth‐pastes using different types of nat‐ tants, emulsifiers, emolents, emulsion stabilizers, struc‐ ural raw materials and their combinations with the pur‐ ture‐forming agents (gel‐forming components) and pose to select most effective and rational samples from thickeners. At the same time they should enrich cosmetic the point of view of functional and consumer properties products with those curative and prophylactic properties (cheap including). Below we discuss how to estimate which they reveal when used in medicine. cosmetic attractiveness of product as objectively as poss‐ Here is given general characteristics of those dis‐ ible. cussed natural materials, of course, within the frames Among natural raw materials used in our composi‐ concerning cosmetology. tions here we focus our attention on different types of a Clay is the product of chemical destruction of the clay material. Namely, as they say in cosmetology, white rocks, making a basis of soils, ground, sedimentary clay (china clay) – kaoline, blue clay – bentonite and pe‐ breeds. Its basic components – compounds of aluminum, loid, or curative mud, the basis of which also contains silicon, iron, small amounts of sodium, magnesium, cal‐ clay skeleton. cium, potassium. Non‐clay inclusions – mica materials, It was interesting to find out what functions in a cos‐ chlorites, fine quartz, feldspath, zeolites and organic par‐ metic product clays and peloids can execute according to ticles. The general indices of clays are the small size of their chemical, mineralogical structure and natural prop‐ particles (<5 micron), laminated structure and presence erties. of structural hydroxyl groups in silicates. Clay is capable The interest to this question was reflected in the re‐ to form paste‐like, easily stirred mass which may be giv‐ port of our group members “Color clays of Georgia in en any form. The main part of clay consists of colloidal cosmetics” published in materials of 2nd International hydrate of silicon earth and the alum earth, determining Conference of Ceramists Association of Georgia in 2009.

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its major physical properties. From the point of view of change processes in integuments, normalizes operation of cosmetics, the silicon contained in clay stimulates hair sebaceous and sweat glands, helps elimination of microbi‐ growth, an exchange of lipids, formation of collagen and al disbalance, has keratolytic effect, stimulates maturation a bone fabric, gives elasticity to vessels and positively in‐ of collagen structures, provides bactericidal, fungicidal and fluences on false skin (epidermis). Aluminum possesses anti‐inflammatory properties. The substantial sorptive ca‐ drying and binding properties, manganese disinfects, pacity and complicated phase structure makes mud an ef‐ deodorizes and dries the skin. fective peeling and cleansing agent, promotes regenera‐ Peloids are natural formations consisting of water, tion of skin cover. In cosmetic products it serves first of all the mineral and organic substances, having fine dis‐ as a structure forming component. persed structure, homogeneity and salve‐like consis‐ Let’s consider the types of clays and peloids, which tence. They possess plasticity, a high thermal capacity are presented in our work. It’s kaoline, bentonite and and slow heat emission, contain biologically active sub‐ volcano mud. stances and live microorganisms. Oxide content of a crys‐ The table presents oxide contents of kaoline from talline skeleton of peloids is close to clays. Jvarisa deposit (Tkibuli area), bentonite from Askana de‐ The most complicated complex of biologically active posit (Ozurgeti area) and volcano mud from Akhtala de‐ substances, macro‐ and the micro‐ components containing posit (Gurjaani area). in peloids, intensify microcirculation of blood and all ex‐

Table 1 Oxide contents of clays and peloid, %

Material SiO2 Al2O3 Fe2O3 FeO CaO MgO Na2O K2O H2O MnO TiO2 SO3 Kaoline Jvarisa 64,96 20,74 4,69 1,13 0,53 1,48 6,44 Bentonite Askana 60,34 22,21 2,04 0,84 2,72 4,87 0,24 0,19 7,05 0,04 0,25 Peloid Akhtala 53,1 16,1 5,7 7,0 3,2 2,0 2,6 1,0

As to mineral structure, in kaoline is kaolinite Bentonite (blue clay) is porous clay, a product of vol‐

Al4[Si4O10](OH)8, in bentonite – montmorillonite (Ca, Na...) canic ash, consists basically of montmorillonite group

(Mg, Al, Fe) 2 [(Si, Al) 4O10] (OH) 2∙nH2O, in volcano mud – minerals. Aluminosilicate layers consist of three lattices: montmorillonite and illite (Al(OH)2 ((Si, Al) 2O5)) ∙K (H2O). one octahedral and two tetrahedral lattices. In the cen‐ Kaoline (white clay, china clay) is a mineral from alu‐ ters tetrahedrons are located atoms of silicon and in the minosilicates group. Silicate of aluminum with small ad‐ centers of octahedrons – atoms of aluminum. At interac‐ mixture of calcium and magnesium silicates. Hygroscop‐ tion of minerals with solutions crystal lattice is expand‐ ic, possesses high plasticity, adhesive and absorbent ing. Bentonite possesses high adsorptive capacity, ability properties. Cleans false skin (epidermis), has antiseptic to swelling and ion exchange. It can act as the catalyst in and skin surface regenerating effect; stimulates human biochemical reactions and in contact with skin covers, as well. For bentonite is typical solidification, suspendability body protection, saturates epidermis with minerals; pre‐ and jelling properties. It activates blood circulation and vents expansion of microbes due to it’s property to ab‐ intensifies exchange process in skin cells. It is nontoxic, sorb toxins and pollution; simplifies cellular regenera‐ stable in a wide interval of pH and temperatures. Bento‐ tion, stimulating an exchange. Kaoline gives flexibility to nite is used in emulsion creams and lotions, provides skin upper layer vessels, promotes formation of collagen bleaching effect and quick removal of excess skin fat. It is which, in turn, makes skin more elastic. Kaoline is rec‐ used in range of cosmetic products for thickening, emul‐ ommended to be included in cosmetic compositions, in‐ sification of oils and suspensions. tended for a dry, loose and sensitive skin. It strengthens Curative muds differ genesis, place of formation, the hair, reduces their brittleness and loss. In tooth‐pastes chemical and mineralogical content and specificity of cura‐ kaoline, replacing a chalk, does not demand surfactants tive and prophylactic action. There are practically all types any more for creation of paste consistency, thus carrying of peloids in Georgia, from which, at the given stage, we out abrasive functions, it removes tooth stones and have selected volcanic mud of the Akhtala deposit, which strengthens enamel. was used for treatment already in X‐XI centuries.

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In cosmetic compositions this mud can carry out It was already said about role and functions of clays functions of gel‐forming component and a source of mi‐ and peloids in these compositions and in cosmetic prod‐ croelements. By the way, gel‐forming substances are the ucts in general. Now, briefly, about other ingredients in components defining visual quality of a cosmetic prod‐ these compositions. uct, affecting on the consistency and stability at storage. It is clear, that extracts and tinctures of herbs are giv‐ In the light of the new term (cosmeceutics), clays and ing their specific curative and prophylactic properties to peloids are considered not only as gel‐forming sub‐ a cosmetic product. In our mixtures the following plants stances, but also components, in many respects defining are listed: burdock, origanum, sweetflag (calamus), am‐ curative and prophylactic properties of cosmetic product. brosia, chamomile, orange, sage, mint, melisse, juniper. Moreover, it is possible to use pure clays and peloids It’s possible to say about their specific curative and in medicine and cosmetology as separate medical prod‐ prophylactic properties which each of them possesses: uct, but it is also possible to use them as components of the burdock – is used for treatment of skin diseases, more complicated mixtures. In our compositions they helps growth and strengthening of hair; origanum – pos‐ usually, are “diluted” with mineral water, herbal infusions sesses anti‐inflammatory, antimicrobic, sedative proper‐ and extracts, etc. ties; calamus – is applied against loss of hair, for greasy Before passing to the discussion of our compositions, skin care, has the anti‐inflammatory properties; ambro‐ let’s say briefly about properties of the cosmetic prod‐ sia – possesses anti‐inflammatory and anti‐allergenic ucts defining effect of their application. Each cosmetic properties; chamomile – has emollient action on skin irri‐ preparation consists of a base and an active component. tation, is used as anti‐inflammatory, antiseptic, anti‐ Value and speed of diffusion, i.e. process of absorption spasmodic, softening agent; orange – possesses moisten‐ of active substances is defined by many physiological and ing and softening properties, is useful for dry skin; sage – physico‐chemical factors. It is possible to define several has anti‐inflammatory and tanning properties on a head parameters of basis and active component which can skin, narrows sebaceous channels; mint has softening have influence on cosmetic product effect. and strength restoring properties; melisse – is used for For a basis these are: flowing (ability to spreading), care of a dry and greasy, sensitive and ageing skin; the since well spreading products improve contact between juniper regulates activity of sebaceous glands, has anti‐ components and skin; viscosity – low viscosity increases septic properties, strengthens hair roots. speed of active component transfer from a basis; occlu‐ Five different curative mineral waters of Georgia are sive ability – influences hydration and skin swelling; pH used in our compositions. Placing them into recipes was value – defines physico‐chemical state of active sub‐ motivated by two reasons: first, because it was desirable stances and thus, determines the conditions of dissolving to enrich cosmetic products with all those specific to in carrier – basis. curative mineral waters properties and second, Georgia Properties of an active component imply: the solubili‐ so is rich with mineral waters of various contents and re‐ ty characteristic – the active component with worse so‐ spectively different functions, that missing such oppor‐ lubility conditions releases better from the basis; its po‐ tunity would be wrong. Actually mineral waters in our larity; diffusion factor; distribution factor; concentration compositions are not only simple solvents, but they also of a component; duration, quantity, the area and a me‐ saturate cosmetic product with direct curative and thod of application. prophylactic potential. For example, the use of mineral All these parameters characterize cosmetic product. waters from Biisa and Borjomi containing fluoride accor‐ It should be noted, that cosmetic effect of using of this or dingly 32 mg/l and 10 mg/l in tooth‐pastes directly pro‐ that preparation is the response reaction on the part of vide anti‐caries effect and cavity protection action. the object expressed in normalization and activation of Other mineral waters in our compositions – from de‐ physiological properties of skin covers. posits of Tbilisi, Nunisi, Tskhaltubo are chosen mainly ac‐ We demonstrate developed compositions of some cording to the two indices: first, because of their low mi‐ cosmetic products containing clays and peloid. These are three compositions of the shampoos, three compositions neralization, i.e. they will not overload cosmetic products of the tooth‐paste and two compositions of a cream‐ with excess of salts, and second, their curative action in mask. Their samples are stored in our laboratory within case of skin diseases is well known. already six months.

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Table 2 Structures of cosmetic means, %

Shampoo # 1 Shampoo # 2 Clay Askana 20,4 Clay Askana 18,9

NaHCO3 1,1 NaHCO3 1,0 Burdock alcohol extract 1,2 Burdock alcohol extract }3,8 Origanum castoric extract 0,8 Calamus alcohol extract Mineral water Tskaltubo 76,5 Origanum oil extract 0,6 Mineral water Nunisi 75,7

Shampoo # 3

Mud Akhtala 31,7 NaHCO3 0,6 Sodium laurilsulphate 0,6 Ambrosia tincture 12,7 Sodium Carboxymethyl Cellulose 0,5 Chamomile tincture 12,7 Glycerin 1,2 Ethanol 4,4 Odorant 0,1 Origanum castoric extract 3,2 NaCl 0,6 Mineral water Tbilisi (Lisi) 31,7

Tooth paste # 1 Tooth paste # 2 Kaoline 60,1 Clay Askana 55,6 Sodium benzoatum 0,3 Sage alcohol extract Sorbitol 0,6 Mint alcohol extract }11,1 Glycerin 9,0 Melisse alcohol extract Orange tincture 7,5 Mineral water Borjomi 33,3 Vanillin ‐ Mineral water Nunisi 22,5

Tooth paste # 3 Kaoline 46,0 Coloring agent ‐ Glycerin 6,5 Juniper alcohol extract 1,6

NaHCO3 0,1 Juniper oil extract 1,6 NaCl 1,1 Mint alcohol extract 3,3 Honey 1,3 Vanillin 0,1 Menthol ‐Mineral water Biisa 39,4

Cream Mask # 1 Cream Mask # 2 Mud Akhtala 46,1 Clay Askana 12,5 Soy milk 38,5 Lanoline 37,5 Beeswax 7,7 Peach kernel oil 37,5 Honey 7,7 Vitamin E 10 dr. Mineral water Nunisi 12,5

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There are small amounts of traditional components in shampoo №3: sodium laurilsulphate – surfactant, wash‐ ing and foaming component, acting more softly, than other analogs; sodium carboxyl methyl cellulose – carries out thickener, stabilizer and gelling agent functions; gly‐ cerin – emulsifier, promotes active mixing of a mixture components, keeps them in a suspended condition for a long time; cooking soda (NaHCO3) is necessary for main‐ tenance of environment pH. In a tooth‐paste №1 sodium benzoatum – preserva‐ tive; sorbitol – is moistening, texturing substance. Honey in shampoo №3 and in cream‐mask №1 – is a stimulator of a salt and grease exchange; beeswax – structure‐ forming component. In cream‐mask №2 lanolin softens, gives elasticity, promotes metabolism of the skin; peach oil is included into a base of cosmetic composition. 3. CONCLUSION Soy milk in a cream‐mask №1 needs special notice. Use of different types of clays and also a curative We actively mix this component into different kinds of muds in cosmetic compositions enabled replacement of cosmetic compositions – shampoos, creams and lotions some chemical components and provided functional and and we are discovering its new and unknown features consumer properties of cosmetic products. and functions in cosmetics. Patent application for use of Simultaneous use of medical mineral waters and soy milk in cosmetic compositions is made. extracts of herbs in compositions synergistically and The perception by the consumer of a cosmetic prod‐ purposefully increased curative and prophylactic properties of products. It allows calling products cos‐ uct as a skin, hair and teeth care solution is in a great meceutic. deal determined by the influence of that product on sense organs and first of all, what sort of tactile feelings References causes a product (sensory properties of a product). Ob‐ 1. L. Bokuchava, D. Nizharadze. Fundamentals of perfu‐ jective methods of measurement are not enough to es‐ mery and cosmetics. Georgian Technical University, timate these subjective feelings. Under modern ap‐ Tbilisi, 2004. proaches, using of sensorial estimation testing method, it 2. L. Bokuchava, N. Bokuchava, D. Jincharacdze. Raw ma‐ is possible to estimate sensory properties of a cosmetic terial of perfumery‐cosmetic production. Georgian product with acceptable accuracy (and repeatability), by Technical University, Tbilisi, 2007. involving standard mixtures and strict observance of test‐ 3. N. Bokuchava, D. Bibileishvili, I. Berdzenishvili, L. Eba‐ ing instructions. This method supposes participation of noidze. Coloured clays of Georgia in cosmetics. II In‐ examinees, well trained in sensorial estimation. ternational Conference and Exhibition of Georgian It is necessary to establish also typical, subjectively Ceramists’ Association, Tbilisi, 7‐10 October, 2009, experienced feelings and the sequence of their percep‐ p.122‐127. tion. The quantitative estimation is made by examinees 4. L. Ebanoidze, I. Memanishvili, N. Bokuchava, M. Mi‐ for each sensory parameter with the help of a number kaia, N. Spiranti. Receipt of therapeutic‐pro‐ scale. Uniting the results received from each of exami‐ phylactic cosmetic products (cream, lotion) on the nees, the so‐called sensory profiles are received, the ex‐ basis of natural raw material. Trans. of Interna‐ ample of which is presented on drawing. tional Scientific‐Practical Conference “Innovation The samples of all presented compositions were on Technologies and Contemporary Materials” Kutai‐ trial in core organization for toxic and hygienic tests. It si, 2010, p.392‐393. was concluded, that samples do not render irritating ac‐ 5. N. Bokuchava. Healing muds of Georgia. Georgian tion, do not change a functional condition of a human Technical University. Tbilisi, 2009, p.37‐100. skin, and also, that product meet the hygienic norms for 6. V.E. Slastenenko, B.A. Polivoda. All about cosmetics the preparations of the given class. and cosmetic agents. Fenix, Rostov‐na‐ Dony, 2009.

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7. Yu. Dribnokhod. Kosmetics and cosmetology. ID “Ves” 9. M. Polevaya. Healing clay, medicinal muds. ID “Ves” Sankt‐Peterburg, 2002. Sankt‐Peterburg, 2004. 8. I.I. Krasnyuk. Therapeutic‐cosmetic agents. “Academa” 10. H. Kutz. Cosmetic creams and emulsions. Content, 2006, p.93‐120. receipt, test methods. “Kravel”Ltd. M. 2004.

uak 615.1(075.8) kaolinis, bentonitisa da peloidis Semcveli kosmetikuri saSualebebis recepturebis SemuSaveba d. jinWaraZe, n. bokuCava qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 69, saqarTvelo.

reziume: damuSavebulia sxvadasxva saxeobis kosmetikuri saSualebebis - Sampunebis, kbilis pastebis, krem-niRbebis recepturebi, sadac kaolini, betoniti da peloidi cvlis tradiciul qimiur ingredientebs da mrecxavi, damarbilebeli, Jeles Semqmneli, qafwar- momqmneli, matonizirebeli funqciebis Sesrulebis garda produqts aniWebs maTTvis damax- asiaTebel samkurnalo-profilaqtikur Tvisebebs. samkurnalo mcenareebis eqstraqtebisa da samkurnalo mineraluri wylebis Setana, Tavis mxriv, aniWebs produqts samkurnalo- profilaqtikur Tvisebebs. es safuZvels iZleva miRebul saSualebebs kosmecevtikuri vu- wodoT.

sakvanZo sityvebi: kaolini; bentoniti; peloidi; talaxi; Tixa; kosmecevtika; fuZe; aqtiuri komponenti; receptura; Sedgeniloba.

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UDC 666.946.6 STUDY OF DOLOMITE FROM THE SKURI DEPOSIT FOR RECEIVING HIGH REFRACTORY COMPOSITE M. Balakhashvili, N. Nizharadze, D. Gventsadze, M. Mshvildadze, Z. Kovziridze Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava str., Tbilisi 0175, Georgia.

E‐mail: [email protected] This already makes it interesting for refractory materials Resume: High refractory carbon containing compo‐ receiving on dolomite basis. Thermographic and X‐ray site is received with addition of different carbon contain‐ structure analysis has been carried out for studying do‐ ing materials on dolomite‐serpentinite clinker. For re‐ lomite phase transformations. ceiving of clinker the Skuri (Tsalenjikha) deposit dolomite Thermal analysis has been carried out on derivato‐ 0 and the Tsnelisi deposit serpentinite are chosen. graph G‐1500D with average rate of heating 10 C/min in 0 The fitness of the Skuri deposit dolomite for receiving 20‐1000 C temperature interval. of high refractory composite is studied. On the thermogram of dolomite from the Skuri depo‐ Technical carbon, carbon fiber and coal wastes are sit two endothermic effects (Fig.1) are marked out with 0 0 chosen as additives. The content of these components in maximums at 810 C and 870 C which is characterized for 0 the composition is stated when the material shows its dolomites. At 810 C happens the decomposition of 0 best exploitation properties. MgCO3 and extended endopeak (maximum 870 C) cor‐ The researches are performed with the methods of responds to CaCO3 separated from dolomite and also to thermographic and X‐ray structure analysis and the me‐ that CaCO3 which in this rock is presented with a small thods of studying thermal and mechanical properties. amount of calcite which is confirmed with the results of X‐ray structural analysis (Fig.2). X‐ray structural analysis was carried out on diffrac‐ Key words: dolomite; serpentinite; clinker; high re‐ tometer ДРОН‐3. X‐ray pattern shows a small amount of fractory composite; additive. calcite, CaCo3, while the main component is CaMg(CO3)2, the diffraction maximums of which are d ‐ 3.690; 1. INTRODUCTION hkl 3.020; 2.665; 2.537; 2.190; 1.803 Ǻ. With consideration A number of researches have been carried out in or‐ of all obtained results the use of the Skuri deposit dolo‐ der to receive base composition refractories [1‐4]. Do‐ mite is possible for receiving dolomite‐serpentinite lomite and magnesium hydrosilicate raw material [5‐8] clinker. are studied. In Georgia this problem is of particular im‐ Chemical analysis and thermogram of the Tsnelisi portance as here magnesite raw material is not quarried deposit serpantinite are presented in Table 2 and Fig.3. and if needed refractory materials are imported from Chemical composition of serpentinite shows that SiO abroad. Thus, for receiving base refractories we used do‐ 2 content in it is 37.22% and MgO amount is 39.36 mass%. lomite and adding magnesium hydrosilicate serpentinite Differential curve of serpentinite heating (Fig.3) we received clinker. shows that comparatively small amount of water, hy‐

groscopic water is removed at 1100C. The remained 2. THE BODY OF THE ARTICLE amount of water is constitutional water which is re‐ The presented work envisages the study of the Skuri moved at 500‐6000C and in this process crystal lattice is (Tsalenjukha) deposit dolomite for receiving dolomite‐ disturbed. It is that endothermal effect on thermogram serpentinite clinker and receiving and study of carbon with maximum at 6700C is connected with the loss of this containing composite on the basis of clinker. water. Serpentinite transformation into stable waterless In order to receive clinker we have chosen the Skuri magnesium silicates is egsothermal process and is cor‐ (Tsalenjikha) deposite dolomite and serpentinite from responded with maximum at 8700C. In order to receive the Tsnelisi deposit. clinker, dolomite and serpentinite were broken, pow‐ From chemical analysis of dolomite it is evident (Ta‐ dered, mixed and moulded into briquettes and baked at ble 1) that it is distinguished with small content of oxide 14500C, regime – 50/min. admixtures and its basic components are CaO and MgO.

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Table 1 Chemical analysis of the Skuri deposit dolomite

Oxides composition, mass%

SiO2 Al2O3 CaO MgO FeO Fe2O3 P2O5 MnO SO3 TiO2 Na2O K2O Heating loss

‐ 2,04 32,25 19,93 ‐‐ 0,08 0,12 0,02 0,14 0,03 1,3 0,1 45,8

Fig. 1. Thermogram of dolomite from the Skuri deposit

Fig.2. Diffractogram of dolomite

Table 2 Chemical composition of serpentinite Name of raw Oxides composition, mass%

material SiO2 Al2O3 Fe2O3 CaO MgO SO3 MnO R2O Heating loss Humidity serpentinite 37,22 1,70 8,20 0,56 39,36 0,3 - 0,13 12,20 0,32

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Fig. 3. Thermogram of serpentinite from the Tsnelisi deposit

Differential‐thermal analysis of dolomite‐serpentinite small endothermal effects with maximums at 410, 510, mixture and clinker has been carried out. 670 and 8000C are presented which are connected with On differential curve of the mixture (curves DTA, hydrated minerals dehydration, while endoeffect (1200C) DTG, TG) endothermal effects are fixed with maximums is caused with the loss of adsorption water. at 625, 780 and 8700C which are characteristic to dolo‐ Phase composition of clinker was studied with the mite and serpentinite (Fig. 4.1). The Figure presents method of X‐ray phase analysis on example of the sam‐ thermogram of dolomite‐serpentinie clinker. On DTA ple baked at 14000C (Fig.5).

Fig. 4. Thermograms of dolomite‐serpentinite mixture and clinker

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Fig. 5. X‐ray pattern of dolomite‐serpentinite clinker

As it is seen from the given data (Fig.5) X‐ray pattern For sample preparation clinker, coal wastes and silicon shows diffraction maximums characteristic to periclase were at first broken, then powdered, moulded into sam‐ o 0 (2.425; 2.109; 1.489Ǻ), C3S (2.775; 2.736; 2.599; 1.760; ples and baked in silite furnace at 1400 C, regime 5 /min.

1.644Ǻ), C2S (2.283; 1.627Ǻ). Each mixture was taken in amount of 100 g. (Table 3).

Table 3 Composition of mixture and main properties

Composition of mixture, mas % Physical‐chemical indices

‐ ‐ ‐

C ‐ , ‐ ‐ 0

car σ

den C 3

coal resis 0 fiber %

ctori poro comp

‐ phite

(1300 ‐

nical bon sity, Clay buli ‐ g/cm waste ‐ Water sity, Silicon Clinker ression Sample ness, –water) Gra Refra Open strength, Tki mate Carbon tance Thermal Apparent Tech 1 90 10 _ _ _ _ _ 10 58,8 25,2 2,31 1770 6 2 85 15 _ _ _ _ _ 10 21,3 41,05 2,08 1770 6 3 85 _ 7,5 7.5 _ _ _ 12 58,3 11,6 2,60 1580 6 4 80 _ 10 10 _ _ _ 12 65,1 20,0 2,58 1550 6 5 70 _ 15 15 _ _ _ 12 _ _ _ <1500 _ 6 90 _ _ _ 10 _ _ 10 62,8 23,9 2,41 1770 6 7 85 _ _ _ 15 _ _ 12 96,8 17,8 3,1 >1770 7 8 90 _ _ _ 8,5 1,5 _ 10 67,0 24,2 2,45 1770 7 9 85 _ _ _ 12,75 2,25 _ 10 101,4 1,38 2,99 1770 7 10 95 _ _ _ _ _ 5 10 70,5 20,7 2,22 1770 7 11 94 _ _ _ _ _ 6 10 42,0 31,2 2,16 1770 7 12 85 _ _ 15 _ _ _ 11 69,9 4,02 2,67 1770 7

Thus, studying the effect of variation of carbon con‐ tained when 15% technical carbon is added. In this case taining additives amount on the main properties of the high refractory composite is received the ultimate com‐ received composites shows that the best result is ob‐ pression strength of which is 96.8 MPa. The improved

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results are obtained at adding of silicon together with With consideration of these data technical carbon, technical carbon (sample 8‐9) when 5% carbon fiber the Tkibuli coal waste and carbon fiber are selected as (sample 10) and 15% coal waste are used (sample 12). carbon containing additives.

Fig.6. Thermograms of materials: 1. Technical carbon; 2. Technical carbon and clinker mixture; 3. Sample 7; 4. Clinker and coal waste mixture; 5. sample 12

On the curve of technical carbon heating (Fig.6.1) noted that on the thermogram of technical carbon (Fig. from 4500C begins exothermal process of carbon oxida‐ 6.1) oxidation (burning) process continued to 10000C. tion (burning) with maximum at 5600C which continues The last exoeffect in the mixture was fixed at 8100C. to 10000C. Mass loss is 75.2%. Mass loss of mixture makes 20.1%. On thermogram of technical carbon and clinker mix‐ It means that only a part of carbon was burnt out of ture (Fig.6.2) at 4000C a small value endoeffect (Fig. 4.2) mixture. is noticed, then endoeffects characteristic to clinker are On the thermogram of roasted samples (No 7) (Fig. marked out which are covered with carbon exoeffect 6.3) only an unimportant endoeffect is detected at 1000C with maximums at 630 and 8000C. At 8500C endoeffect is which should be connected with adsorption water loss. noticed which is characteristic for clinker. It should be

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Other effects are not detected and mass loss is not no‐ stance consisting of calcium aluminates and alumofer‐ ticed either. rites. On DTA of clinker and coal waste mixture (Fig. 6.4) X‐ray patterns of composites received with addition mainly endoeffects characteristic to clinker are pre‐ of different additives on the basis of clinker are pre‐ sented which differing from Fig. 6.2 are not overlapped sented in Fig. 7. with exoeffect of technical carbon waste which is unim‐ On X‐ray pattern of all composition samples the ref‐ portant compared to technical carbon exoeffect. Ther‐ lexes characteristic to three‐calcium silicate are pre‐ mogram of the sample received with roasting of the sented with quite high intensity (dhkl ‐ 3.04; 2.736; 2.745; same mixture (sample 12) is analogous to thermogram 2.309; 2.30; 2.188; 1.766Ǻ) except sample 11 (Table 3) of sample 7 (Fig. 6.5). It means that carbon containing where peaks characteristic to α and β form two calcium composite is received with a definite phase composition silicate are more notable (dhkl ‐ 4.70; 2.885; 2.745; 2.695; which does not change at heating. This indicates the ex‐ 2.46; 2.235; 2.02; 1.928Ǻ). The same r X‐ray pattern istence of thermally stable calcium silicate in its compo‐ shows diffraction maximum characteristic to carbon (dhkl sition which is very important at production of articles. ‐ 3.38Ǻ) which is also fixed on carbon containing sample As a result of clinker investigation with the method of 12. On the roentgenogram of all samples, the peaks cha‐ X‐ray structural analysis it is stated that its component racteristic to periclase are of almost the same intensity phases are alit, belit, periclase and intermediate sub‐ (dhkl ‐ 2.103; 1.488Ǻ).

Fig. 7. Diffractograms of carbon containing composites : 1. ‐ 11; 2. ‐ 7; 3. ‐ 12; 4. ‐ 9

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3. CONCLUSION 3. I.M. Glushchenko, O.F. Dolgikh, A.Yu. Melnichuk. On The Skuri deposit dolomite is studid and its suitability the possibility of production of nonburning periclase‐ for clinker receiving is stated. carbon items. Refractories, 1991, No 12, p.21‐23. High refractory carbon containing composite can be 4. Author’s certificate 147 944 USSR – K.B.Simonov, received from dolomite‐serpentinite clinker. Ya.G.Gaponov, A.M.Chuklei. Discoveries, inventions, The effect of carbon containing additives amount var‐ 1989, No 18, p.59. iation on mechanical indices of the composite is studied. 5. O. Mchedlov‐Petroyan. Usage of serpentinite in na‐ The best results received at addition of the following tional economy. Conference works on chemistry of amounts of components are stated (mass %): cement. Promstroiizdat, 1956, p.67‐77. 1. Technical carbon ‐ 15; 6. I.G. Ochagova. Information review. Refractory produc‐ 2. Carbon fiber ‐ 5; tion. Institute “Chermetinformatsia”. 1985, ch.1. 3. Coal waste ‐ 15. 7. E. Zedginidze, N. Nizharadze, D. Adamia. Dolomite‐ serpentinite refractories for casing of sintering zone References of cement‐calciners. Collection of scientific works. 1. C.M. Roak, V.I.Shubin. Periclase‐belite refractory for GruzNIIstrom. Tbilisi, 1987, p.67. sintering zone of rotating furnaces. Tsement. 1971. 8. Z. Kovziridze, N. Nizharadze, V. Kinkladze, N. Nepa‐ No 10. p. 18‐20. ridze, M. Balakhashvili. Refractory composites receiv‐ 2. I.S. Kainarski, E.V. Degtiareva. Main refractories. Mos‐ ing on the basis of dolomite‐serpentinite clinker. Ce‐ cow, Metalurgizdat, 1977, p.367. ramics, 1(18), 2008, Tbilisi, p.10‐12.

uak 666.946.6 skuris sabados dolomitis Seswavla maRalcecxlgamZle kompozitis misaRebad m. balaxaSvili, n. niJaraZe, d. gvencaZe, m. mSvildaZe, z. kovziriZe qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi, 0175, kostavas 69, saqarTvelo.

reziume: maRalcecxlgamZle naxSirbadSemcveli kompoziti miRebulia dolomit- serpentinitur klinkerze sxvadasxva naxSirbadSemcveli masalis damatebiT. klinkeris misaRebad SerCeulia skuris (walenjixa) dolomiti da wnelisis sabados serpentiniti. Seswavlilia skuris sabados dolomitis vargisoba maRalcecxlgamZle kompozitis misaRe- bad. danamatebis saxiT SerCeulia teqnikuri naxSirbadi, naxSirbadis boWko da qvanaxSiris narCenebi. Ddadgenilia am komponentebis Semcveloba, romlis drosac masala amJRavnebs saukeTeso saeqspluatacio Tvisebebs. kvleva Catarebulia Termografiuli, rentgenostruqturuli analizis, Termuli, da meqanikuri Tvisebebis Seswavlis meTodebiT.

sakvanZo sityvebi: dolomiti; serpentiniti; klinkeri; maRalcecxlgamZle kompoziti; danamati.

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UDC 539.143.43 INDUCTIVE EXCITATION OF MAGNETOELECTRIC RESPONSES IN LAYERED MAGNETOELECTRIC COMPOSITE MATERIALS USING A MAGNETIC VIDEO‐PULSE EXCITATION М. Chikovani*, А. Akhalkatsi*, T. Gavasheli*, G. Mamniashvili**, Т. Gegechkori**, D. Gventsadze*** *Javakhishvili Tbilisi State University, 3, Chavchavadze Av. Tbilisi 0128, Georgia; **Andronikashvili Institute of Physics, 6, Tamarashvili St. 0177, Tbilisi, Georgia; ***Dvali Institute of Machine Mechanics, 10, Mindeli Str., Tbilisi, 0186, Georgia.

E‐mail: [email protected] change at influence of the second RF pulse interacting Resume: Magnetoelectric responses excitation at ap‐ with an acoustic signal excited by the first RF pulse. plication of magnetic video‐pulses was studied in a num‐ In work [4] the method of works [1,3] was used for ber of layered magnetoelectric‐piezoelectric composites investigation of magnetoacoustic response properties in consisting of alternative ferrite‐piezoelectric, nickel‐piezo‐ these materials following each RF pulse of periodic train electric and phosphate‐magnetite‐nickel (or cobalt) layers. of RF pulses, and further in [5] it was used for study of The intensity of the observed magnetoelectric voltage in ferrite‐piezoelectric (FP) layered composite with electric fabricated layered composites makes them interesting for recording of magnetoelectric signal using silver contacts practical applications in smart sensors and transducers. on outer piezoelectric layers of composite with the PFPFP structure. The analysis of magnetoacoustic responses investiga‐ magnetoelectrics; layered composites; Key words: ted in [4] showed their similarity with ones observed in magnetostriction, piezoelectricity, bioceramics, magnetic [1]. video‐pulse excitation. Besides this it was shown that these magnetoacous‐ tic responces were apparently formed by the same mag‐ 1. INTRODUCTION netostrictive mechanism related with the domain wall Different types of magnetoacoustic responses were displacement as in the case of the DAE. observed in magnetostrictive materials after excitation Further experimental investigations are necessary to of a magnetostrictive sample by radio‐frequency (RF) clear out the DAE and magnetoacoustic response nature pulses and magnetic video‐pulses (MVP) [1‐4]. and finding out new magnetostrictive materials with In work [1] a slab shaped ferrite sample was excited strong magnetoacoustic responses to the excitation by by a train of RF pulses of 0.5 μs width with 10 ms repeti‐ RF and MVP. tion period and at 5 МHz frequency. The ring‐down Duriny the recent years the great attention was paid magnetoacoustic signals were observed after termina‐ to study the multilayered FP composites consisting of tion of each RF pulse, in the RF pulse train. The Fourier comparatively thin alternating films of these materials transformation of these signals gives a series of equally showing so‐called magnetoelectric effect making them spaced peaks with spaces between them depending on perspective for development of new type smart sensors sample’s geometry. Using these data for the slab shape and transducers [6]. sample one could find acoustic wave velocity in this ma‐ In these materials the deformation of the ferrite due terial and compare it with similar data obtained with to the magnetostriction effect at influence of external ac other methods [2]. magnetic field results in the deformation of the piezoe‐ In work [3] the domain‐acoustic echo (DAE) signals, lectric layer that is mechanically coupled to the ferrite. possessing a long‐time memory, were excited by three This results in a change in the polarization of the pie‐ RF pulses using a pulse NMR spectrometer in ferrites, zoelectric layer accompanied by the formation of the iron borate and ferrite‐piezoelectric composites at 20 bound charges on the ferrite‐piezoelectric interfaces

MHz frequency. and, as result, in the appearance of voltage UМЕ generat‐ The formation of DAE in these materials was ex‐ ed on the structure surfaces. Such multilayered struc‐ plained by irreversible processes of magnetization tures reveal the particularly large ME effect which is cha‐ racterized by a large value of magnetoelectric voltage

169

U factor α = ME , where d is the total thickness of E (,hd ) piezoelectric layers in the structure and h is the ampli‐ tude of ac magnetic field, in contrast with a comparative‐ ly weak magnetoelectric effect observed in natural sin‐ gle‐phase magnetoelectrics. In work [7] a comparatively simple method was sug‐ gested for wide‐band magnetoelectric characterization of a ferrite‐piezoelectric multilayer structure using MVP Fig. 2. Magnetoelectric сomposite sample: F – ferrite; influence. The procedure involves measuring of magne‐ P – piezoelectric; K – silver contacts. toelectric response of sample to the application of MVP. In Fig. 3a the oscillogram of a magnetoelectric re‐ This method allows to avoid frequency limitations re‐ sponse of PFPFP composite sample at excitation by MVP lated with the inductance of the coils used to produce is presented. For comparison in Fig.3b we present the the ac magnetic field in methods so far used to study the oscillogram of the magnetoelectric response generated magnetoelectric characteristics of samples. at application of 20 MHz frequency PF pulse of the same sample which was inductively excited in the resonance 2. THE BODY OF THE ARTICLE coil of pulse NMR spectrometer [5]. For investigation of magnetoacoustic responses gen‐ erated at application of MVP with amplitude up to 500 Oe and duration up to ~ 5 μs there was used installation similar to the one first used in [7], Fig. 1.

Fig. 3. а) Magnetoelectric response to excitation by magnetic video‐ pulse. Upper beam shows the time location of magnetic video‐pulse; lower beam presents magnetoelectric response.The full oscilloscope beam sweep is 50 μs. b) Oscillogram of a magnetoelectric response in the layered PFPFP composite at excitation by a train of RF pulses with filling frequency 20 MHz and repetition rate 3⋅103 Hz and RF pulse du‐ ration 3 μs. The full oscilloscope beam duration is 100 μs. Oscillo‐ grams were taken at zero outer magnetic field and room temperature. Time moment t соrresponds to the end of RF pulse. Fig. 1. Magnetic video‐pulse excitation set‐up: e 1. Pulse generator; 2. Current pulse amplifier; 3. Voltage‐pulse amplifier; 4. Oscilloscope; 5. Silver contacts; 6. Piezoelectric layer; In Fig. 4 there are presented the results of signal in‐ 7. Ferrite layer tensity (I) measurements in arbitrary units (a.u.) of PFPFP The set‐up for MVP generation used by us in work [8] composite magnetoelectric signal in dependence on the to study domain wall dynamics by NMR echo method value of outer biasing magnetic field (Ho) directed along with influence of additional MVP excitation was used as the surface of the sample at different amplitudes of a unit for generation of MVP. magnetic video‐pulse (Hd). The magnetoelectric responses at excitation by MVP Let us present further the results of the similar study were generated in layered slab shaped FP composite of nickel‐piezoelectric structure PNiPNiP where a com‐ sample consisting of five layers of material with PFPFP mercial nickel foil and piezoelectric layers with thick‐ 3 structure and 10 x 6 x 1 mm dimensions, consisting of nesses 0.15 mm and 1 mm, respectively, were used. The ferrite usually used in a TV induction coil and as a piezoe‐ sample had 5 layers of 15 х 10 х 1 mm3 dimensions. lectric layer ‐ СеTiPb ceramics. The magnetoelectric vol‐ In Fig. 5. it is presented the obtained intensity de‐ tage UМЕ was removed from silver contacts on two outer pendences of magnetoelectric signal on the value of piezoelectric layers of the composite (Fig. 2). baiasing magnetic field Ho directed along the surface of a

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sample at different values of MVP amplitude Hd for The composite material was treated in a laboratory PNiPNiP composite. alternative mill during 15 minutes, after which it was consolidated in press mould at 130 – 160ºС temperature and 50 МPa pressure during 15 minutes. After consolida‐ tion samples were subjected to thermal treatment in the electric furnace at Т=400оС during 2 hours. As it is known, the thermal treatment at temperature exceeding 300оС imparts phosphates with insolubility property in water and improves their mechanical proper‐ ties. In Fig. 6а and 6b there are presented the magnetoe‐ lectric response signal intensities of the synthesized phosphate‐magnetite composite with Co and Ni com‐ mercial powder additives with mean grain size ~ 10 μm, respectively.

Fig. 4. Magnetoelectric signal intensity dependence on biasing outer

magnetic field Ho at different amplitudes of magnetic video‐pulse

Hd. The duration of magnetic video‐pulse τm =1 μs;

о – Hd=15 Ое; ♣ ‐ Hd=37 Ое; ‐ Hd=75 Ое;.

‐ Hd=110 Ое; • ‐ Hd=150 Ое.

Fig. 5. Magnetoelectric signal intensity dependence on the value of

biasing magnetic field Ho at different amplitudes of magnetic video‐ pulse Hd in PNiPNiP composite.

Fig. 6. Magnetoelectric signal intensity dependence

The duration of magnetic video‐pulse τm =1 μs; on the value of biasing outer magnetic field Ho at different values of magnetic video‐pulse Hd in а) Нd= 180 Oe; b) Нd= 450 Oe ; c) a) phosphate‐magnetite‐nickel composite: at I) Н = 150 Oe; II) Н = 375 Oe and III) Н = 525 Oe. Н = 500 Oe; d d d d b) phosphate‐magnetite‐cobalt composite: at Similar investigations were also carried out on the I) Нd= 7.5 Oe; II) Нd= 300 Oe; III) Нd= 450 Oe and IV) Нd= 570 Oe. μ magnetoelectric composite containing the layer of a new The duration of magnetic video‐pulse τm =1 s; magnetostrictive material on the basis of yttrium phos‐ 3. CONCLUSION phate synthesized by us. The results of study of magnetoelectic signals gener‐ Among its precursor components yttrium phosphate ated at application of magnetic video‐pulses in a number (14 %) in the form of a white powder was used as bound‐ of layered composites consisting of alternating layers of ing material. Other components were magnetic and magnetostrictive and piezoelectric materials are pre‐ nickel (or cobalt) powders taken in 4:1 ratio. sented in the work.

171

In difference to multilayered magnetoelectric sam‐ Acknowledgements ples (NZPO‐PZT) studied in work [7], our samples con‐ The work has been supported by the Georgian Na‐ tained smaller number of layers (up to 5) at their larger tional Science Foundation Grant N GNSF/ST07/7‐248. thickness (up to 1 mm).

Samples in work [7] contained 11 layers of NZPO References and10 layers of РZТ at thickness 8 μm each and dimen‐ 1. J. Park, S. Lee, I. Yu, and Y. Seo. Sensors and Actua- sions 5.9 х 7.3 mm2. Although values of magnetoelectric tors. A140, 84 (2007). voltage U , ~ 10 mV and factor α in the samples stu‐ МЕ Е 2. V.I. Khizhny, V.V. Tarakanov, A.P. Koroljuk, T.M. died by us were smaller than in work [7] almost by an Khizhnaya, Low. Temp. Phys. 32, 638 (2006). order, nevertheless magnetoelectric signal UМЕ in our 3. G.Mamniashvili, Y.Sharimanov, A.M. Pohorily, samples was sufficiently intensive. For this reason and O.M. Kuzmak. J. Appl. Phys. 105, 07A504 (2009). due to the simplicity of their preparation they could 4. G.Mamniashvili, Y.Sharimanov, T.Gegechkori. Jour- present a practical interest for their use in sensors and transducers as well as functional materials – implantants nal of the Georgian Ceramists’ Association ISSN in medicine where bioceramics on phosphate basis are 1512-0325. 1-2(20-21), 200 (2009). widely used [9]. 5. G.Mamniashvili, Y.Sharimanov, T.Gegechkori, It is interesting to note that the magnetoelectric re‐ A.Akhalkatsi, A.M. Pohorily, O.M. Kuzmak. Func- sponse dependence on the value of baising of outer tional Materials 7, N3 (2010) (to be published). magnetic field observed in phosphate‐magnetite‐nickel 6. G. Srinivasan. Annual Review of Material Research. (or cobalt) resembles one observed in work [7] in sam‐ 40, 153 (2010). ples prepared on the basis of ferrite what could be ex‐ 7. Y.K. Fetisov, K.E. Kamentsev, A.Y. Ostashchenko, G. plained by corresponding change of magnetostrictive Srinivasan. Solid State Communication. 132, 13 (2004). factor λ under influence of outer magnetic field in fer‐ 8. A.Akhalkatsi, G.Mamniashvili, T.Sanadze. Appl. rites [7]. In nickel‐piezoceramics composite a similar de‐ Magn. Res. 15, 393 (1998). pendence was close to one observed for the magnetoac‐ 9. P. Parhi, A. Ramanan, A.R. Ray. Amer. J. Biochem.& oustic response intensity dependence on outer magnetic Biotech. 2, N2, 60 (2006). field in work [4].

uak 539.143.43 magnetoeleqtruli rezonansis induqciuri agzneba fenovan magnetoeleqtrul kompoziciur masalebSi magnituri videoimpulsiT zemoqmedebisas m. Ciqovani*, a. axalkaci*, c. gavaSeli*, g. mamniaSvili**, t. gegeWkori**, d. gvencaZe*** *ivane javaxiSvilis Tbilisis saxelmwifo universiteti, Tbilisi, 0128, WavWavaZis gamz. 3, saqarTvelo; **andronikaSvilis fizikis instituti, TamaraSvilis 6, Tbilisi, 0177, saqarTvelo; ***dvalis manqanaTa meqanikis instituti, mindelis 10, Tbilisi, 0186, saqarTvelo. reziume: gamokvleulia magnetoeleqtruli signalebis generacia magnituri video- impulsebis moqmedebisas fenovan kompozitebSi, romlebiც Sedgeba magnetoeleqtruli da ferit-piezoleqtrikis, nikel-piezoeleqtrikis da magnetoeleqtrikis tipis piezoeleq- truli monacvle fenebisagan fosfat-magnetitis bazaze. damzerili magnetoeleqtruli signalis intensivoba da nimuSebis damzadebis simartive sainteresod xdis maTi praqtikuli gamoyenebis SesaZleblobas sensorebsa da mimRebebSi. sakvanZo sityvebi: magnetoeleqtrikebi; fenovani kompozitebi; magnetostriqcia; piezoe- leqtroba; biokeramika; magnituri videoimpulsuri agzneba.

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UDC 621.894 DEVELOPMENT OF HIGH‐TEMPERATURE ECOLOGICALLY CLEAN FRICTION MATERIALS OF NEW GENERATION AND STUDY OF THEIR WEAR PROPERTIES L. Gventsadze Republic Center for Structure Researches, Georgian Technical University, 77, Kostava st., 0175, Tbilisi, Georgia

E‐mail: [email protected] low speed braking, noise at high speed movement, de‐ Resume: The nanoporous polymer friction materials crease of braking performance at heating of the brake sys‐ on the basis of modified phenol‐formaldelyde resin and tem above 350°C, instability (falling down) of the high index diatomite, modified by liquid silane, carbon black and friction coefficient at moment of transition from dry to wet basalt fibre have been developed. The physico‐chemical friction and a brake disk high wear intensity. and tribology properties of these materials were studied It should be noted that the most of serially produced using friction machine IM‐58. It was shown that these brake pads are characterized with the above mentioned de‐ materials are characterized with stable friction coeffi‐ fects and as compared with the asbestos containing brake cient and good wear stability at high temperature in the pads they are more expensive. From the fact that the as‐ range of 500 – 6000C. The friction materials developed bestos containing brake pads production is prohibited by environment protection organizations, the actual scientific‐ by us and low‐metallic (LM) and non‐asbestos organic technical problem is the finding out of new ways to produce (NAO) pad materials from the USA and EU markets were the new non‐asbestos braking pad materials. tested. The tests carried out using the pin‐on‐disc ma‐ To eliminate the above mentioned defects in the ex‐ chine indicated the advantage of developed materials isting non‐asbestos brake friction materials, the creation and it was shown that these materials form a considera‐ of nanoporous composite materials with improved tribo‐ bly smaller amount of airborne wear particles than the logical properties at dry friction (braking) high tempera‐ conventional materials and the wear products of the lat‐ ture conditions is necessary. It was established that the ter contain not more then 5 elements while in foreign simplest way to produce such materials is the introduc‐ analogs this number was greater than 7‐9. tion of ultradisperse powder [7], every particle of which

Key words: phenol resin; diatomite; basalt; friction contains a definite number of nanosize pores and in or‐ der to achieve this goal we used one of natural Georgian coefficient; wear intensity; pin‐on‐disc machine. raw materials – diatomite. The surface structure investigations of non‐modified 1. INTRODUCTION and modified samples were done on the laboratory The leading firms of the world such as Reimark (USA), stand (friction machine IM‐58), and on the scanning elec‐ Beral, Texstar (Germany), Mintex Don, Ferodo (England), tron microscope (SEM) (DSM‐960, OPTON, Germany). In Reitecks, Valeo (France), etc. produce friction materials these investigations it was clearly revealed that the wear for cars without asbestos‐cancerogenic material. As as‐ stability of all materials is in correspondence with the bestos substitution they use different type artificial and standard exploitation requirements which in our opinion natural fibres‐glass, steel, carbon and basalt fibre, ara‐ is stipulated by diatomite content and ware mechanism mide (Kevlar type) cellulose fibre and so on. According to conditioned by its nanoporousity, as it was explained by statistical data, Georgian import frictional products con‐ Prof. Kutelia in works [7,8]. tain approximately 70 % of asbestos. Scientists are looking for different technology methods 2. THE BODY OF THE ARTICLE to create structures with unique asbestos properties. One We developed three types of friction material (I,II,III) on of them is the creation of pores and the introduction of as‐ the basis of phenol‐formaldehyde resin one of which was bestos substituting ingredients to the composites [1‐6]. modified by silane liquid, the second one by technical car‐ In spite of the fact that the produced non‐asbestos bon, and the third one by basalt fiber. Their common main brake pads satisfy main technical requirements (high fric‐ components were diatomite and barite. Friction material tion factor, stable brake regime, brake unit operation capa‐ samples were pressed as rods (Ø15mm) and tubes (Ø28 bility preservation at high temperature ~350°C), most of mm x Ø20 mm) at 170°C temperature and 70 MPa pres‐ them have definite shortcomings, as follows: squeaking at sure. Physico‐mechanical and tribological properties of

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these materials were studied using friction machine IM‐58 was set to a flow rate of 7.7 m3/h. The filter (D) was used at 0.7 MPa pressure loading, stepwise increasing of friction to ensure particle‐free inlet air. speed at 0,25 m/sec rate from the 2 m/sec speed. The corresponding investigations of the modified pin‐ The main instru‐ optical particle counter (Grimm ment used to Aerosol Technik, Ainring, Germany), on‐disc machine where also carried out where along with measure particles which measures particles, developed materials one LM material from EU market and was a GRIMM 0.25‐32µm in size, in 31 size intervals one NAO pad material from the USA market were tested condensation nucleus counter (TSI, The second in‐ [9]. The pin‐shaped samples were Ø10 mm in diameter and Shoreview, NM, USA), which meas‐ strument was 15 mm high. The actual size, shape and elemental compo‐ ures the number concentration of P‐Trak sition of the wear particles generated from different mate‐ airborne particles 0.02–1 µm in size aerosol monitor (TSI, Shoreview, NM, rials and accumulated on filters were examined. The third instru‐ USA), which records the mass con‐ The pin‐on‐disc machine is presented in Fig. 1. The ma‐ ment was a centration in mg/m3 (weigh) of air‐ chine runs under stationary conditions with constant ap‐ DustTrak borne particles 0.1–10 µm in size plied normal forces up to 100 N and at constant rotational speeds up to 3 000 rp/m. A load cell is used to measure the During testing, the pump collected airborne wear tangential force acting on the pin. The nominal contact particles on filters. A volume of approximately 6 dm3 of pressure was 0.4 MPa, typical of light braking that reduces air was pumped through Nuclepore polycarbonate filters the speed of a vehicle but does not stop it. The coefficient with pore size of 0.4 µm (Whatman, Maidstone, UK). of friction was calculated as the measured tangential force The particles collected were analyzed using SEM and EDX divided by the applied normal force. (energy‐dispersive X‐ray spectroscopy) [9]. The samples were in contact for 30 min with gray The obtained results, including speed data, are pre‐ cast‐iron disc (the corresponding sliding distance was sented in Table 1. 13.5 km). Each material combination was tested twice As it is seen from Table 1, the operational range of (the disc was 63 mm in diameter and 6 mm thick). non‐modified friction materials is up to 400°C tempera‐

ture, because at this moment a drastic decrease of fric‐ tion coefficient is fixed and in spite the fact that the wear stability is satisfactory the braking effectiveness is low. The developed friction materials are characterized by the stable friction coefficient and high wear stability at high temperatures, among them one modified by carbon black is distinguished by its indices which was explained by us as due to the formation of percolation heat con‐ ducting channels by carbon nanoparticles the existence of which positively influences on the dry friction process. Fig. 1. Schematics of the test equipment. A: room air; B: fan; In the extreme conditions (500‐600°C approximately) its C: flow measurement system; D: filter; E: flexible tube; wear index is not more than 2,5‐10‐9, the friction coeffi‐ F: clean air inlet ; G: closed chamber; H: pin‐on‐disc machine; I: pin sample; J: air outlet, measurement points; cient is lower as compared to other composites, but it is L: dead weight; M: disc sample; N: air inside chamber stable in the whole range of study. The introduction of basalt fiber increases the friction coefficient, but the In these tests closed chamber was used to control wear resistance 2‐3 times decreases at high tempera‐ the cleanliness of the air surrounding the test samples. tures, nevertheless it is high and satisfy the standard re‐ The fan (B) draws room air (A) into the chamber (G) via a quirements. Introducing fibre we can control at demand flow measurement system (C) and a filter (D) and finally the friction factor and possibly improve the technology through the air inlet opening (F). The air in the chamber parameters at processing of linings during their massive (N) was well mixed due to the complicated internal vo‐ production. Composite I is distinguished by aesthetic co‐ lume of the pin‐on‐disc machine (H) and the high air ex‐ lour (white‐yellow) and is the lightest of all composites. change rate. The air in the chamber transported the The developed materials do not squeak and following generated particles to the air outlet (J), where particle wetting tests showed that the decrease of friction factor measurement sampling points were situated. The fan is insignificant and is soon recovered.

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Table 1 Physico‐chemical and tribological properties of developed nanoporous friction materials.

‐9 Friction coefficient, μ Wear intensity, J ⋅ 10

Friction MPa 3

material σ density

compression kg/m %

type absorption,

d, 200°C 380°C 600°C 200°C 380°C 600°C Specific strength, Water Ultimate

Non‐modified material 1570 85 0.36 0.40 0.19 ‐ 5.7 7.7 ‐

I - material modified 2065 118 0.30 0.40 0.29 0.47 4.8 4.5 6.7 by silan

II - modified carbon 2068 145 0.34 0.33 0.31 0.37 1.1 2.3 2.5 black

III - modified basalt 2460 137 0.54 0.54 0.33 0.42 2.15 5.42 8.3 fiber

As per disc wear (Table N 2) where we take ZHMX the operation with samples II and III, the wear is again brand cast‐iron discs, it wears most during operation at minimal. 2000C with the non‐modified material, than with I, II and At 6000C the cast‐iron disc operating with sample I III materials. The minimum wear 0,3‐0,39∙10‐10 in the experiences the wear intensity which is equal to 0.6∙10‐ range of wear intensity is observed. 10, while with sample II it is equal to zero, and with sam‐ At 3800C cast‐iron does not experience the wear due ple III it is equal to 0.39∙10‐10, which is explained by the to the decrease of friction coefficient, and it is most sub‐ great value of friction coefficient and the presence of fi‐ jected to the wear at operation with sample I, but during bre in the composite. The results of inrestigation on the modified pin‐on‐ Table 2 disc machine are presented in Fig. 2 and Fig. 3.

Disc wear intensity, J ⋅ 10‐-10

2000C 3800C 6000C type

Friction material

Non‐modified material 1.60 0 _

I - material modified 0.80 1.0 0.6 by silan

II - modified carbon 0.30 0.25 0 black

Fig. 2. The mean coefficient of friction (µ) and the pin III -modified basalt fi‐ 0.39 0.21 0.39 temperature (T ) after running-in. Black column: bre pin first test; white column: second test.

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In Fig. 2 the mean values after running‐in for the It should be noted that the study of airborne wear measured coefficient of friction and pin temperature are particles collected on filter of all three instruments using presented. The figure shows that for friction materials SEM and EDX showed both their size and shape as well developed by us friction coefficients are approximately as their elemental composition and it was established 0.41, 0.3 and 0.32 and are again in the correspondence that in wear products of friction materials developed by with the obtained by us results with tube‐like samples. us there was not presented more than 5 elements, while Though it should be noted that during the rod friction in foreign analogs their content was 7‐9 times higher. the overlapping coefficient is aiming to zero, but the The obtained results confirm the advantage of devel‐ tube friction is realized torsionally and the overlapping oped materials as compared with the market available coefficient K is of the order of unit. It is seen from figure ones and their high wear stability is stipulated by the that at similar conditions of testing (at the second test‐ wear mechanism which was explained by Prof. Kutelia. ing), the materials worked out by us (particularly sample It could be noted that the work carried out during the II) develop the lowest indices (110‐120°C) which proba‐ second test presents the airborn particle distribution, bly could be explained by the existence of perculative collection and analysis method for particles originated at channels and a different friction mechanism. As per LM the pin and disk contact in the laboratory. The compara‐ and NAO materials their surface temperature is about tively low wear index and sufficiently high coefficient of 200°C. friction points to the necessity of further study of nano‐ porous brake pad linings developed by us.

3. CONCLUSION As it follows from the all above mentioned, it could be said that materials developed by us went through differ‐ ent and original tests on two different stands. The ob‐ tained results of the tribological properties study con‐ firmed their identity. The following conclusion can be drawn from the present work:

• Two nanoporous friction materials developed by us (II and III) are distinguished by high wear resistance and at the same time they generate considerably fewer airborne wear particles as compared with the studied by us friction materials available in the foreign market.

• It is confirmed that the stability limit of tribo‐

Fig. 3. The mean concentrations after running-in as measured us- logical parameters of materials developed by us is 500‐ ing the GRIMM (c ), P-Trak (c ), and DustTrak (c ) GRIMM P-Trak DustTrak 600°C and they contain 5 elements in the wear products instruments. Black column: first test; white column: second test. (as compared with more than 7‐9 in wear products of

foreign ones). In Fig. 3 the mean concentration values of particles for the last 10 minutes (after running‐in) measured with Acknowledgement GRIMM, DustTrak, and PTrak instruments are presented. It is seen from the figure that wear particles mean con‐ I wish to express my gratitude to my advicer Prof. centrations measured by three instruments are mainly in Elguja Kutelia and Prof. Ulf Olofsson for their great help correspondence with each other and the lowest concen‐ during the implementation of this work. trations are characteristic again for our samples II and III References which are worn less of all ones. It turned out that sample 1. France presentation N 2581149, SPK D69/02, 1986. I at the repeated tests was better than NAO material but 2. Japan presentation N 60‐151435, SPK F16 D69/02, worse than LM one. 1985.

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3. Great Britain presentation N 2581149, SPK D69/02, 8. L. Gventsadze, E. Kutelia, D. Gventsadze, O. Tsurtsu‐ 1986. mia. The peculiarities of friction and wear resistance 4. New friction polymer/ Mater/+Manuf. ‐7, #3, 1990, of nano porous compositional material with percola‐ p.20. tion thermally conductive channels, V International 5. Russian Patent № 2229634, SPK F16 D69/02, 2002. Conference BALTTRIB 2009, Kaunas, Lithuania, 19‐21 6. M.Z. Levit, N.A. Kraynova, V.I. Izyumova et al. Friction November 2009. and Wear, 2005, Vol. 26, N2, pp.201‐207 [in Russian]. 9. J. Wahlström, D. Gventsadze, L. Olander, E. Kutelia, 7. E. Kutelia, D. Gventsadze, O. Tsurtsumia, R. Datiash‐ L. Gventsadze, O. Tsurtsumia, U. Olofsson. A pin‐on‐ vili, L. Gventsadze.: Friction and wear peculiarities of disc study of nanoporous composite‐based and con‐ the nanoporous composition base brake linings. Pub‐ ventional brake pad materials focussing on airborne lished paper GEN, # 2, 2008 p.69‐76. wear particles. International conference NORDTRIB‐ 2010, Lulea, Sweden, 7‐10 June, 2010.

uak 621.894 axali Taobis maRaltemperaturuli ekologiurad sufTa friqciuli masalebis SemuSaveba da maTi cveTis aspeqtebis kvleva l. gvencaZe saqarTvelos politeqnikuri universitetis struqturul kvlevaTa respublikuri centri, 0175, Tbilisi, kostavas 77, saqarTvelo.

reziume: SemuSavebulia fenoluri fisis da diatomitis bazaze nanoforovani polimeruli friqciuli masalebi, romlebic modificirebulia silanuri siTxiT, teqnikuri naxSirbadiT da bazaltis boWkoTi. Seswavlilia am masalebis fizikur- meqanikuri da tribologiuri Tvisebebi ИМ-58 xaxunis manqanaze. naCvenebia, rom am masalebs axasiaTebs stabiluri xaxunis koeficienti da kargi cveTamedegoba 500-600°C temperaturis farglebSi. SemuSavebuli da evropul da aSS bazarze gavrcelebuli araliTonuri (LM) da uazbesto organuli (NAO) friqciuli masalebis Rero-diskur xelsawyoze gamocdebma aCvena SemuSavebuli masalebis upiratesoba, aseve aCvena, rom maTi cveTisas haerSi warmoiqmneba gacilebiT naklebi cveTis nawilakebi am masalebTan SedarebiT da cveTis produqtebSi 5-ze meti elementi ar fiqsirdeba, rodesac ucxour analogebSi 7_9-ze metia.

sakvanZo sityvebi: fenoluri fisi; diatomiti; bariti; xaxunis koeficienti; cveTis intensivoba; Rero-diskuri xaxunis xelsawyo.

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UDC 666.95 PECULIARITIES OF SYNTHESIS OF SELENIUM‐CADMIUM RED ENAMELS S. Sanadze, G. Gaprindashvili Department of Chemical and Biological Technologies, Georgian Technical University, 69, Kostava Str. Tbilisi 0175, Georgia

E‐mail: [email protected] metal selenium with solid phase reactions. Their compo‐ Resume: For synthesis of selenium‐cadmium red sition can be expressed with general formula nCdS‐CdSe. pigments at 620‐6500C the chromophores: sulfuric cad‐ mium and metal selenium are used. The reactions be‐ 2. THE BODY OF THE ARTICLE tween the mentioned compounds proceed with forma‐ Selenium‐cadmium chemical compounds unite dif‐ tion of solid solutions nCdS‐CdSe in strong gas reducing ferent pigments from yellow and orange to dark red and medium. New composition fluxes without lead com‐ brown. For example, orange color is received with corre‐ pounds are obtained on the basis of pearlite, boric acid, lation of 0.1‐0.15 mole CdSe per 1 mole CdS, while dark zinc oxide, chalk, soda ash and other chemicals. The neg‐ purple color ‐ with correlation of 1‐1.5 mole per 1 mole ative effect of lead and niter on selenium containing CdS; at CdSe composition less than 0.1 mole per 1 mole enamels is stated. CdSe solid solution is yellow, while CdSe composition of more than 1.5 mole per 1 mole CdS violet tint is received (1). Key words: selenium; cadmium; pigment; flux; gas As seen from the above mentioned relation yellow reducing medium; solid solutions. color of pigment is received at maximum content of sul‐ furic cadmium while the gradual addition of cadmium se‐ 1. INTRODUCTION lenide changes pigment color from orange to red. It The family of red enamels generally unite also purple should be mentioned that the synthesis of selenium‐ coral red and pink enamels the synthesis of which com‐ cadmium red pigments with interaction of sulfuric cad‐ pared to other color enamels is characterized with a mium and metal selenium is analogous to CdCO3 in case number of peculiarities and difficulties. The pigments of of Se and S using, too. the mentioned color artistic enamels can be divided into The major reactions in this case can be represented the following groups: in the following form: 1. Ferriferous; CdCO3 → CdO + CO2; 2. With chrome and chrome‐tin 2CdO + S → CO2 + 2Cd; 3. With selenium‐cadmium Cd + S → CdS; 4. Gold containing purple and pink Cd + Se → CdSe Synthesis of red pigments was performed with ther‐ Heating mal treatment of chromophores – sulfuric cadmium and nCdS + CdSe → nCdS ∙ CdSe at high temperature

The table shows the difference of colors.

Composition, mass.p Pigment color Cadmium carbon Selenium Sulfur Orange 81,50 3,40 15,10 Orange‐red 78,80 6,62 14,58 Red 76,28 9,62 14,10 Bright‐red 71,00 19,00 10,00 Bright‐red 75,00 10,00 15,00 Purple‐red 69,90 14,00 16,10 Bluish‐red 69,90 17,50 12,60

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Small amount of prepowdered charge (CdS 88%, Se tions and on the quality of end product were studied for 12%) is put into shamotte crucible and cylindrical article the first time. Alkaline‐earth oxides MnO, CaO, SrO, BaO prepared from shamotte is put into crucible so that the ar‐ have been tested. It appeared that addition of 0.2‐0.3% ticle be not higher than the main crucible. The purpose of MgO to charge promotes the perfection of synthesis. creation of additional volume in the major crucible is uni‐ The problem of flux composition of the second major form and homogeneous burning of charge, also accelera‐ component of enamel added to selenium‐cadmium pig‐ tion of reaction going on between CdS and Se. The space ment has the most importance. The fluxes containing between main and additional billet is filled with charge lead, boron‐lead and alkali boron‐lead were tested. and covered with ceramic plate, while clearance between It is stated that ZnO content in fluxes in amount of 6‐ crucible and cover is filled with caoline. Burning process at 8% is necessary to receive deep red color of enamel. The 629‐6500C is carried in strict gas recovering medium, the full substitution of ZnO with CaO, BaO, MgO, SrO gives air penetration into crucible is not allowed. We should undesirable result and changes red tint to dark indeter‐ take into consideration that at first burning a part of sele‐ minate colors. nium is evaporated while sulphur is partially burned out Zinc and cadmium are located in one subgroup of pe‐ and in spite of solid cover of crucible there happens their riodic system and are characterized with analogous phys‐ leaking while a great part of charge in crucible reacts with ical‐chemical properties. The latter considerably differs cadmium and less volatile compound CdSSe is formed. At from the properties of the above mentioned elements. further heating of charge the latter is dissociated forming Therefore, without zinc fluxes with calcium and barium sulphur or selenium vapour. As sulphir melting tempera‐ do not give red enamel. Experiments proved the possibil‐ ture is 444,60C, it is natural that compound dissociation ity of using of the mentioned oxides for imparting other happens physical‐chemical properties to enamels. For example, CdSSe → CdSe + S ↑ BaO lowers the boiling temperature of fluxes, produces After the first burning crucible is unloaded from the low temperature enamels and increases the luster of the furnace and cooled to room temperature, pigment is latter. poured out and sifted through 400 coil/cm2 sieve. At vis‐ Multi‐lead (>30%) fluxes have a very bad effect on ual observation after first burning pigment is characte‐ the color of selenium‐cadmium enamels. Artistic ena‐ rized with inhomogeneous color, in different places its mels synthesized by us and tested in picturesque and color is reddish‐orange which proves that reaction be‐ plique‐a‐jour enamelling of ceramics, glass, silver, copper tween CdS and Se is not fully performed. Besides, in and their alloys we became convinced that fluxes with pigment mass the black dot‐inclusions of steel selenium high PbO composition chemically effect on celenium and are still quite numerous, which do not enter into reac‐ generate black PbSe (2); in our opinion on multiple burn‐ tion at first burning. ing selenium red enamels transfer into dark colors which In order to bring the solid phase reactions to the end is connected with PbSe formation. This process is inten‐ the sieved pigment should be burned for the second sively proceeding especially at three, four, five and so on time. The temperature of the second burning is some‐ burning (3,4). how less compared to the first burning and makes 600‐ It is inadmissible to use nitre containing fluxes in se‐ 8200C, while burning duration is ~ 25 min. lenium pigments as niter oxidizes CdS and wipes out red The laboratory tests carried out by us proved that the tinting. above mentioned solid phase reactions need to perform Very high quality fluxes are synthesized on the bases these thermal processes for the third and sometimes of the Paravani pearlite, boron acid, lithium carbonate, fourth time which ensures the synthesis of high quality barium and lead oxides, titanium dioxide, the Abano do‐ pigment nCdS ∙ CdSe. lomite, soda ash, chalk and minimum quantity (<5%) of In the process of selenium‐cadmium pigments syn‐ PbO. thesis the effect of mineralizators on solid phase reac‐

179

3. CONCLUSION References Selenium containing pigments, dyes and enamels 1. B.A. Vizir, V.A.Martinov. Ceramic paints. Kiev. 1964. should be fritted and burned in as much as possible little 2. Collection of articles edited by P.P. Budnikova. Phy‐ time to avoid their decomposition and evaporation. sical‐chemical basis of ceramics. Moscow. 1956. 3. E.Brepol. Artistic enamalling. Leningrad, 1986. 4. A.N.Flerov, M.T.Demina. Technique of artistic enamel, chasing and smithery. Moscow, 1986.

uak 666.95 selen-kadmiumis wiTeli minanqrebis sinTezis Taviseburebani s. sanaZe, g. gafrindaSvili qimiuri da biologiuri teqnologiebis departamenti, saqarTvelos teqnikuri universiteti, Tbilisi 0175, kostavas 69, saqarTvelo.

reziume: selen-kadmiumis wiTeli pigmentis sinTezisaTvis 620_6500C gamoyenebulia qro- moforebi: gogirdovani kadmiumi da liTonuri seleni. reaqciebi aRniSnul naerTebs Soris myari xsnarebis warmoqmniT nCdS ⋅ CdSe mimdinareobs airis Zlier aRmdgen garemoSi. miRebulia axali Sedgenilobis fliusebi tyviis SenaerTebis gareSe perlitis, boris mJavas, TuTiis oqsidis, carcis, kalcinirebuli sodis da sxva qimikatebis safuZvelze. dadgenilia selenis Semcvel minanqrebze tyviis da gvarjilis uaryofiTi gavlena.

sakvanZo sityvebi: seleni, kadmiumi, pigmenti, fliusi, airis aRmdgeni garemo, myari xsna- rebi.

180

JurnalSi `keramika~ JurnalSi agreTve gamoyenebis gamoqveynebuli statiebis SesaZlebelia ganTavsdes sferoebi statiebi Semdeg ZiriTadi Tematika sakiTxebze:

yvela saxis minis, energetika axali teqnika, mowyo- keramikis, keramikuli da mSenebloba biloba sawarmoTa da polimeruli kompozite- warmoebis teqnikuri ga- saxalxo moxmarebis bis, zegamtari masalebis, daiaraReba sagnebi Wiquris da minanqaris, sanedleulo bazis qimia da qimiuri teq- sxmuli qvis, ganviTareba, nedleulis nologia mineraluri bambis, racionaluri gamoyeneba, masalaTmcodneoba mWida masalebis, cementis maT Soris adgilobrivi warmoebis narCenebis. metalurgia da sxva araorganuli, resurs- da energodam- eleqtronika da eleq- Zneldnobadi, zogveli teqnologiebi. troteqnika axali da tradiciuli ma- garemos dacva. salis sferoSi medicina sawarmoTa sameurneo optika Catarebuli samecniero moRva-weoba sabazro pi- kvlevebi, robebSi, ekonomika, mar- sxva sferoebi maTi miRebis teqnika da ketingi. garemos dacva teqnologia, nanoteqno- saqarxno gamocdileba. logia da nanoqimia informacia, reklama.

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2(23).2010, 1(24). 2011 s a r e d a q c i o k o l e g i a: i. berZeniSvili, m. bibilaSvili, g. gafrindaSvili (mT. red. moadgile), a. grigoliSvili, g. kakabaZe, m. kekeliZe, z. kovziriZe (mT. redaqtori), r. mamalaZe (mT. red. moad.), m. mujiri, n. niJaraZe (pasuxismgebeli mdivani), a. saruxaniSvili (mT. red. moad.), a. soxaZe, g. tabataZe, r. xuroZe, T. WeiSvili. EDITORIAL BOARD: I. Berdzenishvili, M. Bibilashvili, T. Cheishvili, G.Gaprindashvili (vice-editor-in-chief), A.Grigolishvili, G. Kakabadze, M.Kekelidze, R. Khurodze, Z.Kovziridze (editor-in-chief), R.Mamaladze (vice-editor-in-chief), M.Mujiri, N. Nizharadze (executive secretary), A.Sarukhanishvili (vice-editor-in-chief), A. Sokhadze, G.Tabatadze. kompiuteruli uzrunvelyofa x. ungiaZis redaqtorebi: l. mamalaZe, n. centeraZe

saqarTvelos keramikosTa asociacia 2007 wlidan gawevrianda keramikosTa msoflio federaciaSi

saqarTvelos keramikosTa asociacia 2002 wlidan evropis keramikosTa asociaciis wevria

saqarTvelos keramikosTa asociacia daarsda 1998 wels Jurnali daarsda 1999 wels JurnalSi statiebi ibeWdeba qarTul, inglisur, germanul da rusul enebze

gamoqveynebuli masalis avtorebi pasuxismgebelni arian moyvanili faqtebis, citatebis da sxva monacemebis SerCevasa da sizusteze, aseve Ria publikaciaSi kanoniT akrZaluli monacemis gaxmaurebaze. redaqcias SeuZlia gamoaqveynos masalebi ise, rom ar iziarebdes avtoris Sexedulebebs. Авторы публикуемых материалов несут ответственность за подбор и точность приведенных фактов, цитат и других сведений, а также за неразглашение сведений, запрещенных законом к открытой публикации. Редакция может публиковать материалы, не разделяя точку зрения автора. Authors of the published materials are responsible for choice and accuracy of adduced facts, quotations and other information, also for not divulging information forbidden open publication. Publishing material the editorial board may not share the views of the author.

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