DOCSLIB.ORG

2,799,912 Tem (Particularly Titanium, Zirconium, Hafnium, Thorium

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
2,799,912 Tem (Particularly Titanium, Zirconium, Hafnium, Thorium 2,799,912 Patented July 23, - 1957 2 merci-al manufacture, particularly since in some instances it is very desirable to provide for ‘a ?nal forming step 2,799,912 intermediate the initial forming and ?nal ?ring. In such PROCESSES FOR FQRME’NG HIGH TEMPERATURE instance, it is necessary to bisque ?re or sinter the compact CEIC ARTICLES at very high temperatures to obtain a sufficient hardness where grinding with conventional means is possible. Herbert Hans Gregor, Rockville, Md. Certain improvements over the above sintering method No Drawing. Application December 18, 1950, have been obtained by the addition of small quantities of Serial No. 201,483 r metal, such as cobalt or nickel powder, which causes the 10 carbide to sinter at lower temperatures. The added metal 2 Claims. (Cl. 25-156) is subsequently volatilized in vacuum at high tempera (Granted under Title 35, U. S. Code (1952), see. 266) tures, thus leaving the pure carbide. Yet even this im provement is cumbersome ‘and of limited ?exibility for commercial practice. The present invention relates generally to the fabrica 15 The di?iculties and limitations of current practices are tion of molded high temperature ceramic articles, and essentially avoided and overcome by the process of the more particularly to a process and compositions for the present invention. Considerable freedom is obtained not manufacture of carbide-bonded, boride-bonded, or simi only in iorming the compact, but also in the ?nal prop; larly bonded articles of metal carbides, borides, and like erties of the article by a suitable choice of» molding com a: , compounds by sintering, wherein the bond ‘for the base positions compounded in accordance with chemical equiv particles is formed in situ during ‘the process of manu alents and ratios demanded by reactions which develop ?acturing the articles. The present invention is concerned during the stages of heat treatment. Furthermore, the in its principal application with compounds generally re initial forming methods are not con?ned to dry pressing ferred to as hard carbides and hard bor-ides, which term of the molding compositions, but the forming may also is herein used to refer to the carbides ‘and borides of ' be accomplished in the plastic state, and even slip casting metals of-groups IIVB, VB, and Vl-B of the periodic sys— in plaster or paper molds may be had. Also, very high tem (particularly titanium, zirconium, hafnium, thorium, accuracy is obtained in the form and dimensions of the vanadium, columbium, tantalum, chromium, molybde ?nal article produced. num, ‘and tungsten) and in addition thereto, boron. \In accordance with one embodiment of the present in Hard carbides are used as abrasives and in the manu vention, where a dense carbide article is sought, the desired tacture of high speed cutting tools. \At present, a conven carbide as a ?ller and an appropriate quantity of a react— tional method of preparing carbide shapes =for these pur ant constituting an oxide of a metal which forms a hard poses is by bonding the carbide grain with a high melting carbide, are mixed with a suitable quantity of temporary glass or metal or the like. These conventional binders, binder for intially forming the carbide article. if a porous however, have a very low melting point compared with carbide product is desired, a reactant constituting the those of the carbides themselves, and consequently fail metal itself of the above indicated metal oxide is substituted at low temperatures relative to what the carbides them therefor. The binder should be of such composition that selves can withstand. ‘In order to take advantage of the it decomposes to leave a carbon residue on being heated. hard carbide high melting points, the present invention Hard pitch plasticized with tar has been found suitable provides a process for bonding these high temperature ' as a temporary binder for the present process, although carbides with their own or some other similar hard car other binders of the thermoplastic or thermosetting type bide. in this manner a self-bonded or carbide-bonded can be used. After the article is formed and its binder carbide shape is produced free vfrom extraneous binder, has been carbonized, it is of su?icient strength to permit a which may be used at any temperature which the carbides further or iinal shaping by conventional grinding or other themselves can withstand. machining means. Thereafter, the shape is further heat The hard carbides, carbides of the metals above indi treated under controlled conditions to produce, in the case cated, have melting points in excess of 2000" C., some of the oxide reactant, the cxycarbide of both the react-ant even in excess of 3000° 1C., and these high melting points and the carbide ?ller ingredient, which subsequently lib-_ are shared vwith the nitrides and borides of most of the era-tes its oxygen in combination ‘with the carbon binder mentioned metals. Attempts have been made to sinter to leave a sintered carbide article composed essentially these high temperature materials themselves into molded wholly of carbides. ‘In the case of the metal reactant, the articles; however, they oifer considerable resistance to sin heat treatment results in a direct formation of reactant tering, which may be overcome only when heat treated at metal carbide ‘which sinters with the basic carbide ingre temperatures approaching their melting points. The close dients to leave again a sintered carbide-bonded carbide proximity of their sintering temperatures to their melting article composed essentially Wholly of hard carbides. if points and the resultant lack of su?icient temperature desired, a hard :boride ?ller may be used in place of the range between vsintering and melting causes considerable hard carbide to produce a carbide-‘bonded boride. difficulty in such a direct approach, and this dif?culty is In accordance with another embodiment of the present made more severe by the extremely high temperatures in invention, a hard boride ?ller may be mixed with an volved and the poor means presently available for close oxide of a metal capable of forming a hard boride to ‘temperature control and measurement in these ranges. gether with boron carbide as the reactants, and a suitable One process presently employed ‘for sintering hard car temporary binder decomposable on heating to a carbon bide gr-ains is to press form ?nely divided carbide powder residue is also mixed therewith. This mixture is then having intermixed therewith a suitable quantity of an organic binder, such as Oarbowax. The binder is then heat treated in the same manner as for the previously removed by heating, leaving a fragile compact of carbide indicated embodiment to yield products of similar prop which becomes denser and obtains strength as the heating erties. In the instant embodiment however, the oxygen temperature is increased. There are certain disadvantages of the metal oxide combines with the carbon residue of connected with a fabricating method of this type. The the binder and the carbon of the boron carbide to re; method is limited mainly to pressed compacts of very move both elements from the composition, and as a part simple shape. After removal of the wax they become of this reaction the boron from the boron carbide com; very fragile, which is a ‘very undesirable condition in com bines with the metal of the oxide to produce a bOIld€1 2,799,912 3 4 bonded boride article composed essentially wholly of sets into a hard carbonaceous residue which is suffi borides. ciently strong for further ordinary handling, machining, Broadly stated, therefore, the present invention may be or grinding. Further gaseous substances are given off characterized as a process for producing hard carbide up to a temperature of about l000° C.; so for the re or hard boride ceramic articles, wherein as a ?rst stage moval of most of these gaseous constituents it is desir in the production of such articles a hard carbide or boride able to continue the coking about 600° C., at least to ?ller is temporarily bonded by carbon, and then the 700-800" C. The shapes which are thus produced are carbon is reacted with a metal or metals capable of true in dimension and contour. Occasionally, for simpli forming hard carbides or borides or compounds of such iication of molding dies and pressing operations the ?nal a metal or metals so as to form in situ a hard carbide or 10 shape may be developed after coking through grinding boride bond for the ?ller, leaving the ?nal article essen or machining. The articles thus formed are then heat tially wholly composed of hard borides and/or hard treated in the temperature range of 1800—2500° C. to carbides, as the case may be. And in addition, the obtain transformation of the carbon bond into a carbide present invention further contemplates as within its scope or boride by reaction of the carbon with the reactant. the several compositions essential to carrying out the This heating cycle should be as rapid as possible, and processes here indicated to the desired ends. usually lasts from 20 to 30 minutes. It is therefore one object of the present invention to In the fabrication of dense carbide-bonded carbide provide a method of fabrication of carbide- or boride shapes, it is important that maturity be possible at tem bonded articles of carbides or borides. peratures below 2500" C. For this purpose, a ?uxing Another object of the present invention is to provide a reactant is used in the mixture in the form of an oxide; method of manufacturing precision formed hard carbide for example, a molding powder of titanium carbide may articles.
Load more

Recommended publications
  • Download Article (PDF)
    Recent IUPAC technical reports and recommendations that aff ect the many fi elds of pure and applied chemistry. Making an imPACt See also www.iupac.org/what-we-do/journals/ Standard Atomic Weight of Hafnium elements. For example, radioactive decay of lutetium Revised alters the isotopic composition of hafnium by produc- ing the light isotope of hafnium-176. Thus, some rare The IUPAC Com- terrestrial materials can have abnormal isotopic com- mission on Isotopic positions of hafnium with the most extreme known Abundances and case being sedimentary chert from South Africa hav- Atomic Weights ing atomic-weight value of 178.447. (CIAAW) met under The CIAAW continues to evaluate literature data the chairmanship of which leads to identifi cation of developments in the Dr. Juris Meija (Can- measurement science, recognition of new discover- ada), at the Federal ies, and remains committed to modernize its technical Institute for Mate- guidelines and work towards further expansion of its rials Research and website to include more historical databases. These Testing (bam.de), changes and considerations will be published in Pure Berlin Germany, in and Applied Chemistry [2] and can be found online at June 2019. As IUPAC celebrates its centennial in 2019, the website of The CIAAW (ciaaw.org). its oldest body, the CIAAW, turns 120 with its beginnings tracing back to Berlin in 1899 [1]. Following its 2019 Notes meeting, the CIAAW recommended changes to the stan- 1. For a historical account of the CIAAW, see J.R. De dard atomic weight (i.e. relative atomic mass) of hafnium Laeter and J.
    [Show full text]
  • The Development of the Periodic Table and Its Consequences Citation: J
    Firenze University Press www.fupress.com/substantia The Development of the Periodic Table and its Consequences Citation: J. Emsley (2019) The Devel- opment of the Periodic Table and its Consequences. Substantia 3(2) Suppl. 5: 15-27. doi: 10.13128/Substantia-297 John Emsley Copyright: © 2019 J. Emsley. This is Alameda Lodge, 23a Alameda Road, Ampthill, MK45 2LA, UK an open access, peer-reviewed article E-mail: [email protected] published by Firenze University Press (http://www.fupress.com/substantia) and distributed under the terms of the Abstract. Chemistry is fortunate among the sciences in having an icon that is instant- Creative Commons Attribution License, ly recognisable around the world: the periodic table. The United Nations has deemed which permits unrestricted use, distri- 2019 to be the International Year of the Periodic Table, in commemoration of the 150th bution, and reproduction in any medi- anniversary of the first paper in which it appeared. That had been written by a Russian um, provided the original author and chemist, Dmitri Mendeleev, and was published in May 1869. Since then, there have source are credited. been many versions of the table, but one format has come to be the most widely used Data Availability Statement: All rel- and is to be seen everywhere. The route to this preferred form of the table makes an evant data are within the paper and its interesting story. Supporting Information files. Keywords. Periodic table, Mendeleev, Newlands, Deming, Seaborg. Competing Interests: The Author(s) declare(s) no conflict of interest. INTRODUCTION There are hundreds of periodic tables but the one that is widely repro- duced has the approval of the International Union of Pure and Applied Chemistry (IUPAC) and is shown in Fig.1.
    [Show full text]
  • Three Related Topics on the Periodic Tables of Elements
    Three related topics on the periodic tables of elements Yoshiteru Maeno*, Kouichi Hagino, and Takehiko Ishiguro Department oｆ physics, Kyoto University, Kyoto 606-8502, Japan * [email protected] (The Foundations of Chemistry: received 30 May 2020; accepted 31 July 2020) Abstaract: A large variety of periodic tables of the chemical elements have been proposed. It was Mendeleev who proposed a periodic table based on the extensive periodic law and predicted a number of unknown elements at that time. The periodic table currently used worldwide is of a long form pioneered by Werner in 1905. As the first topic, we describe the work of Pfeiffer (1920), who refined Werner’s work and rearranged the rare-earth elements in a separate table below the main table for convenience. Today’s widely used periodic table essentially inherits Pfeiffer’s arrangements. Although long-form tables more precisely represent electron orbitals around a nucleus, they lose some of the features of Mendeleev’s short-form table to express similarities of chemical properties of elements when forming compounds. As the second topic, we compare various three-dimensional helical periodic tables that resolve some of the shortcomings of the long-form periodic tables in this respect. In particular, we explain how the 3D periodic table “Elementouch” (Maeno 2001), which combines the s- and p-blocks into one tube, can recover features of Mendeleev’s periodic law. Finally we introduce a topic on the recently proposed nuclear periodic table based on the proton magic numbers (Hagino and Maeno 2020). Here, the nuclear shell structure leads to a new arrangement of the elements with the proton magic-number nuclei treated like noble-gas atoms.
    [Show full text]
  • Periodic Table 1 Periodic Table
    Periodic table 1 Periodic table This article is about the table used in chemistry. For other uses, see Periodic table (disambiguation). The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations , and recurring chemical properties. Elements are presented in order of increasing atomic number, which is typically listed with the chemical symbol in each box. The standard form of the table consists of a grid of elements laid out in 18 columns and 7 Standard 18-column form of the periodic table. For the color legend, see section Layout, rows, with a double row of elements under the larger table. below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
    [Show full text]
  • Carbides and Nitrides of Zirconium and Hafnium
    materials Review Carbides and Nitrides of Zirconium and Hafnium Sergey V. Ushakov 1,* , Alexandra Navrotsky 1,* , Qi-Jun Hong 2,* and Axel van de Walle 2,* 1 Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California at Davis, Davis, CA 95616, USA 2 School of Engineering, Brown University, Providence, RI 02912, USA * Correspondence: [email protected] (S.V.U.); [email protected] (A.N.); [email protected] (Q.-J.H.); [email protected] (A.v.d.W.) Received: 6 August 2019; Accepted: 22 August 2019; Published: 26 August 2019 Abstract: Among transition metal carbides and nitrides, zirconium, and hafnium compounds are the most stable and have the highest melting temperatures. Here we review published data on phases and phase equilibria in Hf-Zr-C-N-O system, from experiment and ab initio computations with focus on rocksalt Zr and Hf carbides and nitrides, their solid solutions and oxygen solubility limits. The systematic experimental studies on phase equilibria and thermodynamics were performed mainly 40–60 years ago, mostly for binary systems of Zr and Hf with C and N. Since then, synthesis of several oxynitrides was reported in the fluorite-derivative type of structures, of orthorhombic and cubic higher nitrides Zr3N4 and Hf3N4. An ever-increasing stream of data is provided by ab initio computations, and one of the testable predictions is that the rocksalt HfC0.75N0.22 phase would have the highest known melting temperature. Experimental data on melting temperatures of hafnium carbonitrides are absent, but minimum in heat capacity and maximum in hardness were reported for Hf(C,N) solid solutions.
    [Show full text]
  • Processing of Ores of Titanium, Zirconium, Hafnium, Niobium, Tantalum, Molybdenum, Rhenium, and Tungsten: International Trends and the Indian Scene
    High Temperature Materials and Processes, Vol 9, Nos. 2-4,1990 Processing of Ores of Titanium, Zirconium, Hafnium, Niobium, Tantalum, Molybdenum, Rhenium, and Tungsten: International Trends and the Indian Scene N.P.H. Padmanabhan, T. Sreenivas, and N.K. Rao Ore Dressing Section, Bhabha Atomic Research Centre AMD Complex, Begumpet, Hyderabad, India CONTENTS Page ABSTRACT 218 1. INTRODUCTION 218 2. TITANIUM 219 2.1. International Scenario 219 2.1. Indian Scene 220 3. ZIRCONIUM-HAFNIUM 224 3.1. International Scenario 224 3.2. Indian Scene 227 4. NIOBIUM-TANTALUM 227 4.1. International Scenario 227 4.2. Indian Scene 229 5. MOLYBDENUM-RHENIUM 229 5.1. International Scenario 229 5.2. Indian Scene 237 6. TUNGSTEN 238 6.1. International Scenario 238 6.2. Indian Scene 240 7. CONCLUSIONS 245 REFERENCES 246 217 Vol. 9, Nos. 2-4,1990 Processing of Ores of Titanium, Zirconium, Hafnium, Niobium, Tantalum, Molybdenum, Rhenium, and Tungsten ABSTRACT computers, telecommunications, and superconducting The current international status and Indian scene materials, have brought a host of new metals and on the resource position and processing practice of materials into the limelight. Although they were the strategically important transition metals—titan- known to exist in nature, they were not until recent- ium, zirconium, hafnium, niobium, tantalum, molyb- ly considered to be of much use to mankind. These denum, rhenium, and tungsten—are briefly reviewed. include a number of transition group elements and With the exception of molybdenum these metals are rare earth metals. Due to their special physical, strongly lithophilic, forming stable oxide and silicate chemical, and nuclear properties, newer and more minerals that are resistant to weathering processes.
    [Show full text]
  • BNL-79513-2007-CP Standard Atomic Weights Tables 2007 Abridged To
    BNL-79513-2007-CP Standard Atomic Weights Tables 2007 Abridged to Four and Five Significant Figures Norman E. Holden Energy Sciences & Technology Department National Nuclear Data Center Brookhaven National Laboratory P.O. Box 5000 Upton, NY 11973-5000 www.bnl.gov Prepared for the 44th IUPAC General Assembly, in Torino, Italy August 2007 Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This preprint is intended for publication in a journal or proceedings. Since changes may be made before publication, it may not be cited or reproduced without the author’s permission. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use or the results of such use of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors.
    [Show full text]
  • Processing Development of 4Tac-Hfc and Related Carbides and Borides for Extreme Environments Osama Gaballa Gaballa Iowa State University
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2012 Processing development of 4TaC-HfC and related carbides and borides for extreme environments Osama Gaballa Gaballa Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Mechanics of Materials Commons Recommended Citation Gaballa, Osama Gaballa, "Processing development of 4TaC-HfC and related carbides and borides for extreme environments" (2012). Graduate Theses and Dissertations. 12635. https://lib.dr.iastate.edu/etd/12635 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Processing development of 4TaC-HfC and related carbides and borides for extreme environments by Osama Gaballa Bahig Gaballa A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Materials Science and Engineering Program of Study Committee: Alan M. Russell, Major Professor Vitalij Pecharsky Scott Chumbley Kristen Constant Sriram Sundararajan Iowa State University Ames, Iowa 2012 Copyright © Osama Gaballa Bahig Gaballa, 2012. All rights reserved. ii Table of Contents Abstract 1 Chapter 1: Introduction 4 1.1 Aluminum Silicon
    [Show full text]
  • The Elements.Pdf
    A Periodic Table of the Elements at Los Alamos National Laboratory Los Alamos National Laboratory's Chemistry Division Presents Periodic Table of the Elements A Resource for Elementary, Middle School, and High School Students Click an element for more information: Group** Period 1 18 IA VIIIA 1A 8A 1 2 13 14 15 16 17 2 1 H IIA IIIA IVA VA VIAVIIA He 1.008 2A 3A 4A 5A 6A 7A 4.003 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.941 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 3 Na Mg IIIB IVB VB VIB VIIB ------- VIII IB IIB Al Si P S Cl Ar 22.99 24.31 3B 4B 5B 6B 7B ------- 1B 2B 26.98 28.09 30.97 32.07 35.45 39.95 ------- 8 ------- 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.47 58.69 63.55 65.39 69.72 72.59 74.92 78.96 79.90 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr NbMo Tc Ru Rh PdAgCd In Sn Sb Te I Xe 85.47 87.62 88.91 91.22 92.91 95.94 (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La* Hf Ta W Re Os Ir Pt AuHg Tl Pb Bi Po At Rn 132.9 137.3 138.9 178.5 180.9 183.9 186.2 190.2 190.2 195.1 197.0 200.5 204.4 207.2 209.0 (210) (210) (222) 87 88 89 104 105 106 107 108 109 110 111 112 114 116 118 7 Fr Ra Ac~RfDb Sg Bh Hs Mt --- --- --- --- --- --- (223) (226) (227) (257) (260) (263) (262) (265) (266) () () () () () () http://pearl1.lanl.gov/periodic/ (1 of 3) [5/17/2001 4:06:20 PM] A Periodic Table of the Elements at Los Alamos National Laboratory 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Lanthanide Series* Ce Pr NdPmSm Eu Gd TbDyHo Er TmYbLu 140.1 140.9 144.2 (147) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Actinide Series~ Th Pa U Np Pu AmCmBk Cf Es FmMdNo Lr 232.0 (231) (238) (237) (242) (243) (247) (247) (249) (254) (253) (256) (254) (257) ** Groups are noted by 3 notation conventions.
    [Show full text]
  • Synthesis of Hafnium(IV) Polyaminoacetates
    molecules Article Synthesis of Hafnium(IV) Polyaminoacetates Alexandra T. Shulyak 1,2,*, Evgeniy O. Bortnikov 3, Alexey S. Kubasov 1, Nikita A. Selivanov 1, Alexey A. Lipengolts 4, Andrey P. Zhdanov 1 , Alexander Yu. Bykov 1 , Konstantin Yu. Zhizhin 1 and Nikolai T. Kuznetsov 1 1 Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskiy pr. 31, 119991 Moscow, Russia; [email protected] (A.S.K.); [email protected] (N.A.S.); [email protected] (A.P.Z.); [email protected] (A.Y.B.); [email protected] (K.Y.Z.); [email protected] (N.T.K.) 2 Inorganic Chemistry Department, Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, pr. Vernadskogo, 86, 119454 Moscow, Russia 3 Organic Chemistry Department, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel; [email protected] 4 N.N. Blokhin National Medical Research Center of Oncology, Federal State Budgetary Institution, Ministry of Health of the Russian Federation (N.N. Blokhin NMRCO), Kashirskoye Shosse 24, 115478 Moscow, Russia; [email protected] * Correspondence: [email protected]; Tel.: +7-(916)-823-01-57 Abstract: The interaction of hafnium(IV) salts (oxide-dichloride, chloride, and bromide) with nitrilo- triacetic acid (NTA), diethylenetriamminepentaacetic acid (DTPA), 1,2-diaminocyclohexanetetraacetic acid (CDTA), 1,3-dipropylmino-2-hydroxy N,N,N0,N0-tetraacetic acid (dpta), and N-(2-hydroxyethyl) ethylenediamine triacetic acid (HEDTA) has been studied. The corresponding complexes Na2[Hf(NTA)2]· 3H2O(1), Na[HfDTPA]·3H2O(2), [HfCDTA(H2O)2](3), and Na[Hf2(dpta)2]·7.5H2O·0.5C2H5OH (4) have been isolated and characterized and their structures have been determined by single crystal Citation: Shulyak, A.T.; Bortnikov, X-ray diffraction.
    [Show full text]
  • Hafnium Is Essential to Aerospace Superalloys & Microchips
    Mining the metals of the future Hafnium is essential to aerospace superalloys & microchips Aerospace applications NASA re-entry modules Hafnium’s stability Superalloys for jet engines and strength at Hafnium diboride (HfB2) high temperatures Hafnium is considered is used for ultra high- in both metallic irreplaceable in the MAR M temperature ceramics or and compound 247 superalloy, used in the coatings for components form makes it hot part of jet engines in NASA atmospheric ideal for several (turbine blades and vanes). re-entry modules. aerospace applications Industrial applications Hafnium and its Industrial gas turbines Plasma cutting tips compounds are Hafnium-containing Hafnium is used in not limited to plasma cutting tips and high-temperature superalloys are used in the larger cast parts of welding torches due to aerospace its high melting point and applications, turbines for electricity generation. ability to shift electrons but are used in into the air. industry as well Optoelectronics Having fantastic electrical insulation Integrated circuits Optical Coatings and high-index/low Using hafnium oxide to Thin deposits of hafnium optical absorption replace silicon dioxide oxide provide hard, properties, gate insulators has scratch-free coatings for hafnium oxide allowed a significant leap applications such as has many forward in the quest to near-UV laser applications in the shrink computer chips anti-reflective and optoelectronics and improve efficiency. dielectric mirror designs. industry. Unleashing hafnium’s Thermal reflector potential New cancer treatments Prototypes of thin lamellar Researchers composites of hafnium across the globe Use of hafnium oxide oxide, silicon dioxide and are exploring a nanoparticles in radiation silver are being developed raft of potential oncology to destroy cancer to reflect sunlight back applications for cells is being explored.
    [Show full text]
  • Atomic Weights of the Elements 2011 (IUPAC Technical Report)*
    Pure Appl. Chem., Vol. 85, No. 5, pp. 1047–1078, 2013. http://dx.doi.org/10.1351/PAC-REP-13-03-02 © 2013 IUPAC, Publication date (Web): 29 April 2013 Atomic weights of the elements 2011 (IUPAC Technical Report)* Michael E. Wieser1,‡, Norman Holden2, Tyler B. Coplen3, John K. Böhlke3, Michael Berglund4, Willi A. Brand5, Paul De Bièvre6, Manfred Gröning7, Robert D. Loss8, Juris Meija9, Takafumi Hirata10, Thomas Prohaska11, Ronny Schoenberg12, Glenda O’Connor13, Thomas Walczyk14, Shige Yoneda15, and Xiang-Kun Zhu16 1Department of Physics and Astronomy, University of Calgary, Calgary, Canada; 2Brookhaven National Laboratory, Upton, NY, USA; 3U.S. Geological Survey, Reston, VA, USA; 4Institute for Reference Materials and Measurements, Geel, Belgium; 5Max Planck Institute for Biogeochemistry, Jena, Germany; 6Independent Consultant on MiC, Belgium; 7International Atomic Energy Agency, Seibersdorf, Austria; 8Department of Applied Physics, Curtin University of Technology, Perth, Australia; 9National Research Council of Canada, Ottawa, Canada; 10Kyoto University, Kyoto, Japan; 11Department of Chemistry, University of Natural Resources and Applied Life Sciences, Vienna, Austria; 12Institute for Geosciences, University of Tübingen, Tübingen, Germany; 13New Brunswick Laboratory, Argonne, IL, USA; 14Department of Chemistry (Science) and Department of Biochemistry (Medicine), National University of Singapore (NUS), Singapore; 15National Museum of Nature and Science, Tokyo, Japan; 16Chinese Academy of Geological Sciences, Beijing, China Abstract: The biennial review of atomic-weight determinations and other cognate data has resulted in changes for the standard atomic weights of five elements. The atomic weight of bromine has changed from 79.904(1) to the interval [79.901, 79.907], germanium from 72.63(1) to 72.630(8), indium from 114.818(3) to 114.818(1), magnesium from 24.3050(6) to the interval [24.304, 24.307], and mercury from 200.59(2) to 200.592(3).
    [Show full text]