DOCSLIB.ORG

THE REACTIVITY of SOME TRANSITION METAL NITRIDES and CARBIDES by JEREMY NEIL CLARK a Thesis Submitted to the University of Plymo

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
THE REACTIVITY of SOME TRANSITION METAL NITRIDES and CARBIDES by JEREMY NEIL CLARK a Thesis Submitted to the University of Plymo University of Plymouth PEARL https://pearl.plymouth.ac.uk 04 University of Plymouth Research Theses 01 Research Theses Main Collection 1995 THE REACTIVITY OF SOME TRANSITION METAL NITRIDES AND CARBIDES CLARK, JEREMY NEIL http://hdl.handle.net/10026.1/1891 University of Plymouth All content in PEARL is protected by copyright law. Author manuscripts are made available in accordance with publisher policies. Please cite only the published version using the details provided on the item record or document. In the absence of an open licence (e.g. Creative Commons), permissions for further reuse of content should be sought from the publisher or author. THE REACTIVITY OF SOME TRANSITION METAL NITRIDES AND CARBIDES by JEREMY NEIL CLARK A thesis submitted to the University of Plymouth in partial fiilfilment for the degree of DOCTOR OF PHILOSOPHY Department of Environmental Sciences Faculty of Science in collaboration with British Steel, Teesside April 1995 i i":/-\f"rd(J REFERENCE ONLY 90 0274095 3 UNIVERSiTY OF PLYMOUTH Item No. I c:^002"/4 0953 Date 7 JUN 18§g Class No. ContlNe, LIBRARY STORE THE REACTIVITY OF SOME TRANSITION METAL NITRIDES AND CARBIDES Jeremy Neil Clark ABSTRACT The formation and oxidation of transition metal nitrides and carbides is reviewed and the crystal structures and types of bonding are discussed. Types of nitrides and carbides are categorized in terms of physical and chemical properties and type of bonding. The principles of sintering are summarised. Tlie theory and applications of thermal analytical techniques are reviewed. Surface area determination and estimation of average crystallite size by the BET method utilizing the adsorption of nitrogen gas at -196 X are explained along with the application of x-ray dififractometry ajid scanning electron microscopy to work in this area. In this present research selected transition metal nitrides and carbides have been oxidised in air and carbon dioxide. Activation energies have been determined for these reactions from isothennal oxidations utilizing the Arrhenius equation and from oxidations at different heating rates utilizing the Kissinger equation. Kinetic schemes for the isothermal oxidations have been proposed based on two models of the reactions, that is half order kinetics in which the rate of reaction is determined by the diffijsion of oxidising gas througli the oxide product and two-thirds order kinetics in which the reaction takes place at the surface of a spherical particle of diminishing size as the reaction pioceeds. Surface area measurements and electron microscopy have been utilized to study the ability of the product formed during the oxidations to sinter. X-ray diffractometry has been used to identify the crystal phases present in the initial nitride or carbide and in the oxidation products. The activation energies of the carbides were found to be lower than that foimd for the respective nitrides. At low temperatures the carbides oxidised more extensively than the respective nitrides, but at high temperatures the situation was reversed. Tliis is explained in terms of the difference in the pre- exponential term of the Arrhenius equation. Tlie kinetics were found to be dependent on whether the oxide produced was structurally compatible with the remaining reactant and whether the oxide produced was able to sinter at the temperature used in the experiment. CONTENTS Page Copyright statement 1 Title page 2 Abstract 3 Contents 4 Tables 7 Figures 8 Plates 11 Acknowledgements 12 Author's declaration 13 Chapter 1 INTRODUCTORY SURVEY AND REVIEW 14 1.1 Introduction 14 1.2 Solid-gas reactions 16 1.2.1 Non-porous solid-gas reactions 17 1.2.2 Porous solid-gas reactions 18 1.2.3 Two-thirds and half order reaction kinetics 19 1.2.4 Sintering 20 1.3 Classification of nitrides and carbides 22 1.3.1 Transition metal nitrides and carbides 25 1.3.2 Hagg rules 26 1.3.3 Pauling-Rundle theory 27 1.3.4 Band theory 28 1.3.5 Ubbelohde - Samsanov theory 29 1.4 Production of refractory nitrides and carbides 31 1.5 Oxidation of carbides and nitrides 35 1.5.1 Titanium nitride and carbide systems 35 1.5.2 Zirconium nitride and carbide systems 38 1.5.3 Vanadium nitride and carbide systems 39 1.5.4 Niobium nitride and carbide systems 40 1.5.5 Tantalum nitride and carbide systems 41 1.5.6 Manganese nitride and carbide systems 42 1.5.7 Chromium nitride and carbide systems 42 1.5.8 Iron nitride and carbide systems 42 1.6 Aims of this research 44 Chapter 2 EXPERIMENTAL TECHNIOUES 45 2.1 Thermal analysis 45 2.1.1 Review and introduction 45 2.1.2 The Massflow thermobalance 49 2.1.3 Procedure 56 2.1.4 The STA 781 thermal analyzer 57 2.1.5 Procedure 61 2.1.6 Tube furnace 62 2.1.7 Procedure 62 2.2 Surface area determination 63 2.2.1 Review and introduction 63 2.2.2 The nitrogen sorption balance 70 2.2.3 Procedure 75 2.3 X-ray diffraction 77 2.3.1 Introduction 77 2.3.2 X-ray generator 80 2.3.3 Procedure 81 2.4 Electron microscopy 82 2.4.1 Introduction 82 2.4.2 The Joel JSM-T20 scanning electron microscope 85 2.4.3 Procedure 86 2.5 Products used 88 Chapter 3 RESULTS OF OXIDATIONS IN AIR 90 3.1 Introduction 90 3.2 Oxidation of titanium nitride and carbide in air 91 3.3 Oxidation of zirconium nitride and carbide in air 114 3.4 Oxidation of vanadium nitride and carbide in air 139 3.5 Oxidation of niobium carbide in air 145 3.6 Oxidation of chromium nitride and carbide in air 153 3.7 Oxidation of iron nitride in air 168 3.8 Oxidation of tantalum carbide in air 177 3.9 Oxidation of manganese carbide in air 183 3.10 Effect of addition of chromium carbide on the oxidation of zirconium carbide in air 189 Chapter 4 RESULTS OF OXIDATIONS IN CARBON DIOXIDE 190 4.1 Introduction 190 4.2 Oxidation of chromium nitride in carbon dioxide 191 4.3 Oxidation of iron nitride in carbon dioxide 195 4.4 Oxidation of titanium nitride in carbon dioxide 202 Chapter 5 COMPARISONS AND CONCLUSIONS 204 5.1 Introduction 204 5.2 Comparison between carbides and nitrides 210 5.3 Comparisons within group IVa 211 5.4 Comparisons within group Va 213 5.5 Comparisons across period 214 5.6 Comparison between oxidation in air and carbon dioxide 215 5.7 Conclusions and future work 216 5 .7 .1 Recent research 216 5.7.2 Conclusions 217 5.7.3 Future work 224 References 227 Appendicies 1 Paper published in Thermochimica Acta, 1986, 103(1\ 193-199 243 2 Paper published in Revue de Chimie Minerale, 1987, 24(6), 654-666 251 TABLES Table Page 1 Classification of crystal systems, based on characteristic symmetry 78 2 Isothermal oxidation of titanium nitride in air 94 3 Effect of heating rate on the oxidation of titanium nitride in air 98 4 Isothermal oxidation of titanium carbide in air 108 5 Variation of surface area during oxidation of titanium carbide in air 110 6 Isothermal oxidation of zirconium nitride in air 119 7 Effect of heating rate on the oxidation of zirconium nitride in air 124 8 Isothermal oxidation of zirconium carbide in air 128 9 Variation of specific surface area during oxidation of zirconium carbide and oxide products with temperature and oxidation period 134 10 Isothermal oxidation of vanadium carbide in air 143 11 Isothermal oxidation of niobium carbide in air 147 12 Effect of heating rate on the oxidation of chromium carbide in air 162 13 Isothennal oxidation of chromium carbide in air 165 14 Isothennal oxidation of iron nitride in air 173 15 Isothennal oxidation of tantalum carbide in air 180 16 Variation of specific surface area during oxidation of manganese carbide and oxide products with temperature and oxidation period 186 17 Isothennal oxidafion of iron nitride in carbon dioxide 200 18 Summary of starting materials and oxidation phases observed 205 19 Activation energies for the oxidation of selected transition metal nitrides and carbides determined by Arrhenius and Kissinger methods 208 FIGURES Figure Page 1 Schematic diagram of Massflow thermobalance 50 2 Schematic diagram of Massflow reaction chamber and gas inlet/outlet ports 51 3A Schematic diagram of DTA sample head showing positioning of thermocouples 53 3B Schematic diagram of TG sample head showing position of thermocouple 53 4 Schematic diagram of thermocouple electrical connections 55 5 Schematic diagram of ST A 781 thermal analyser 58 6 Schematic diagram of DTA hangdown assembly and reaction chamber 60 7 The five types of adsorption isotherm in the BET classiflcation 66 8 Schematic diagram CI Electronics Microforce balance 72 9 Chart recorder interface circuit 72 10 Schematic diagram of light microscope, transmission electron microscope and scanning electron microscope 83 11 DTA curves and TG curves for oxidation of titanium nitride in flowing air 92 12 Isothermal TG curves for the oxidation of titanium nitride in static and flowing air 93 13 Arrhenius plot for the oxidation of titanium nitride in air 95 14 Half order and two-thirds order kinetic plots for the isothermal oxidation of titanium nitride in air 97 15 Kissinger plot for the oxidation of titanium nitride in air 99 16 X-ray diflraction traces for titanium nitride and its oxidation products on heating in air at 10 °C min-' 101 17 Isothential TG curves for the oxidation of titanium carbide in flowing air 105 18 Half order and two-thirds order kinetic plots for the isothermal oxidation of titanium carbide in air 106 19 Arrhenius plot for the oxidation of titanium carbide in air 109 20 Surface area changes for 1 hour oxidations of titanium carbide in air 111 2! X-ray diffraction traces of the oxidation products of zirconium nitride 115 22 Isothermal TG curves for oxidation of zirconium nitride
Load more

Recommended publications
  • Sintering of Niobium Containing AISI M2 High Speed Steel
    Sintering of AISI M2 high speed steel with the addition of NbC Alexandre Wentzcovitch1, Francisco Ambrozio Filho1, Luis Carlos Elias da Silva2, Maurício David Martins das Neves2 1Centro Universitário da FEI 2Instituto de Pesquisas Energéticas e Nucleares – IPEN-CNEN/SP [email protected]; [email protected]; [email protected]; [email protected] Keywords: powder metallurgy, high speed steel, NbC, sintering and microstructure. Abstract. The influence of adding 6 wt% (NbC) niobium carbide on the sintering temperature and microstructure of high speed steel - AISI M2 (0.87% C, 5.00% Mo, 6.00% W, 4,00% Cr, 2.00% V and Fe bal.) powder was studied. The starting material was obtained by vacuum melting followed by atomization in water. The samples were axially cold compacted in a cylindrical matrix and then vacuum sintered at 1250 and 1350 °C. Dilatometry and differential scanning calorimetry measurements indicated an increase in sintering temperature with addition of niobium to the AISI M2 steel. Optical and scanning electron microscope observations revealed a microstructure with uniformly distributed niobium carbides. Introduction High-speed steels have been widely used in the manufacture of cutting tools and wear-resistant materials [1]. Several techniques have been used to improve the properties of sintered high speed steels and these include: addition of alloying elements to increase carbide formation [2, 3], addition of ceramic reinforcements and use of high- energy milling [4]. Niobium is an alloying element that can be added to high speed steels to form stable carbides and provide reinforcement to the matrix. The niobium added to the steel combines with carbon to form a MC-type carbide, which can increase the hardness and wear resistance of the high speed steel and prevent austenite grain growth during sintering and heat treatment.
    [Show full text]
  • Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides
    Article pubs.acs.org/cm Thermodynamic Routes to Novel Metastable Nitrogen-Rich Nitrides Wenhao Sun,†,‡ Aaron Holder,§,⊥ Bernardo Orvañanos,‡ Elisabetta Arca,§ Andriy Zakutayev,§ Stephan Lany,§ and Gerbrand Ceder*,†,‡,∥ † Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States ‡ Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States § National Renewable Energy Laboratory, Golden, Colorado 80401, United States ∥ Department of Materials Science and Engineering, Univeristy of California, Berkeley, California 94720, United States ⊥ Department of Chemical and Biological Engineering, Univeristy of Colorado, Boulder, Colorado 80309, United States *S Supporting Information ABSTRACT: Compared to oxides, the nitrides are relatively unexplored, making them a promising chemical space for novel materials discovery. Of particular interest are nitrogen-rich nitrides, which often possess useful semiconducting properties for electronic and optoelectronic applications. However, such nitrogen-rich compounds are generally metastable, and the lack of a guiding theory for their synthesis has limited their exploration. Here, we review the remarkable metastability of observed nitrides, and examine the thermodynamics of how reactive nitrogen precursors can stabilize metastable nitrogen-rich compositions during materials synthesis. We map these thermodynamic strategies onto a predictive computational search, training a data-mined
    [Show full text]
  • Novel Triadius-Like N4 Specie of Iron Nitride Compounds Under High
    www.nature.com/scientificreports OPEN Novel triadius-like N4 specie of iron nitride compounds under high pressure Received: 11 May 2018 Yuanzheng Chen1, Xinyong Cai1, Hongyan Wang1, Hongbo Wang2 & Hui Wang2 Accepted: 2 July 2018 Various nitrogen species in nitrides are fascinating since they often appear with these nitride as Published: xx xx xxxx superconductors, hard materials, and high-energy density. As a typical complex, though iron nitride has been intensively studied, nitrogen species in the iron–nitrogen (Fe-N) compounds only have been confned to single atom (N) or molecule nitrogen (N2). Using a structure search method based on the CALYPSO methodology, unexpectedly, we here revealed two new stable high pressure (HP) states at 1:2 and 1:4 compositions with striking nitrogen species. The results show that the proposed FeN2 stabilizes by a break up of molecule N2 into a novel planar N4 unit (P63/mcm, >228 GPa) while FeN4 stabilizes by a infnite 1D linear nitrogen chains N∞ (P-1, >50 GPa; Cmmm, >250 GPa). In the intriguing N4 specie of P63/mcm-FeN2, we fnd that it possesses three equal N = N covalent bonds and forms a perfect triadius-like confguration being never reported before. This uniqueness gives rise to a set of remarkable properties for the crystal phase: it is identifed to have a good mechanical property and a potential for phonon-mediated superconductivity with a Tc of 4–8 K. This discovery puts the Fe-N system into a new class of desirable materials combining advanced mechanical properties and superconductivity. Nitrogen (N) is the most abundant element in the earth’s atmosphere and is one of the least studied elements regarding the composition of the Earth1.
    [Show full text]
  • Effect of Nitrogen Pressure on the Structure of Cr-N, Ta-N, Mo-N, and WN Nanocrystals Synthesized by Arc Discharge
    Hindawi Publishing Corporation Journal of Nanomaterials Volume 2011, Article ID 781935, 5 pages doi:10.1155/2011/781935 Research Article Effect of Nitrogen Pressure on the Structure of Cr-N, Ta-N, Mo-N, and W-N Nanocrystals Synthesized by Arc Discharge Longhai Shen and Nan Wang School of Science, Shenyang Ligong University, Shenyang 110159, China Correspondence should be addressed to Longhai Shen, [email protected] Received 28 March 2011; Revised 10 June 2011; Accepted 5 July 2011 Academic Editor: Theodorian Borca-Tasciuc Copyright © 2011 L. Shen and N. Wang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The effect of nitrogen pressure on the structure of Ta-N, Cr-N, Mo-N, and W-N nanocrystals formed in arc discharge process was investigated. At the nitrogen pressure of 5 ∼ 20 kPa, the pure cubic-phase TaN and CrN nanocrystals were formed, whereas pure cubic phase of Mo2N and W2N cannot be obtained. A little of metal Mo and a mass of metal W were mixed with the products of Mo2N and W2N, respectively. At the nitrogen pressure of 30 ∼ 50 kPa, subnitride Ta2NandCr2N and metal Cr were gradually formed in the product; furthermore, the proportion of metal Mo and W increased in the product of Mo2N and W2N, respectively. It indicated that the low nitrogen pressure makes cubic mononitride formation favorable. We explain this experimental observation in terms of the evaporation rate of anode metal and the ionization of nitrogen.
    [Show full text]
  • Nanoscale Iron Nitride, Ε-Fe3n: Preparation from Liquid Ammonia
    Nanoscale Iron Nitride, e-Fe3N: Preparation from Liquid Ammonia and Magnetic Properties Anne-Marie Zieschang,1 Joshua D. Bocarsly,2 Michael Dürrschnabel,3 Leopoldo Molina-Luna,3 Hans-Joachim Kleebe,3 Ram Seshadri,*2 Barbara Albert*1 1Technische Universität Darmstadt, Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Alarich-Weiss-Str. 12, 64287 Darmstadt, Germany 2 University of California, Santa Barbara, Department of Chemistry & Biochemistry, Materials Department, and Materials Research Laboratory, University of California, Santa Barbara CA 93106, U.S.A. 3Technische Universität Darmstadt, Department of Materials and Geosciences, Alarich-Weiss-Str. 2, 64287 Darmstadt, Germany ABSTRACT: e-Fe3N shows interesting magnetism but is difficult to obtain as a pure and single-phase sample. We report a new preparation method using the reduction of iron(II) bromide with elemental sodium in liquid ammonia at –78 °C, followed by annealing at 573 K. Nanostructured and monophasic oxygen-free iron nitride, e-Fe3N, is produced according to X-ray diffraction and transmission electron microscopy experiments. The magnetic properties between 2 K and 625 K were characterized using a vibrating sample magnetometer, revealing soft ferromagnetic behavior with a low-temperature average 1 moment of 1.5 µB/Fe and a Curie temperature of 500 K. TC is lower than that of bulk e-Fe3N (575 K), which corresponds well with the small particle size within the agglomerates (15.4 (± 4.1) nm according to TEM, 15.8(1) according to XRD). Samples were analyzed before and after partial oxidation (Fe3N-FexOy core-shell nanoparticles with a 2–3 nm thick shell) by X-ray diffraction, transmission electron microscopy, electron energy-loss spectroscopy and magnetic measurements.
    [Show full text]
  • (12) Patent Application Publication (10) Pub. No.: US 2006/0037529 A1 D'evelyn Et Al
    US 20060037529A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2006/0037529 A1 D'Evelyn et al. (43) Pub. Date: Feb. 23, 2006 (54) SINGLE CRYSTAL AND QUASI-SINGLE Publication Classification CRYSTAL COMPOSITION, APPARATUS, AND ASSOCATED METHOD (51) Int. Cl. (75) Inventors: Mark Philip D’Evelyn, Niskayuna, NY C30B I5/00 (2006.01) (US); Dong-Sil Park, Niskayuna, NY C30B 30/04 (2006.01) (US); Victor Lienkong Lou, C30B 28/10 (2006.01) Niskayuna, NY (US); Thomas Francis C30B 27/02 (2006.01) McNulty, Ballston Lake, NY (US) C30B 21/06 (2006.01) (52) U.S. Cl. .................................. 117/36; 117/13; 117/19 Correspondence Address: Shawn A. McClintic General Electric Global Research One Research Circle (57) ABSTRACT Docket Room K1-4A59 Niskayuna, NY 12309 (US) A Single crystal or quasi-single crystal including one or more (73) Assignee: General Electric Company, Group III material and an impurity. The impurity includes Schenectady, NY (US) one or more elements from Group IA, Group IIA, Groups IIIB to VIIB, Group VIII, Group IB, Group IIB, or Group (21) Appl. No.: 11/249,872 VIIA elements of the periodic table of elements. A compo (22) Filed: Oct. 13, 2005 Sition for forming a crystal is also provided. The composi tion includes a Source material comprising a Group III Related U.S. Application Data element, and a flux comprising one or more of P, Rb, Cs, Mg, Ca, Sr., Ba, Sc., Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, (63) Continuation-in-part of application No. 10/063,164, Mo, Pd, Ag, Hf, Ta, W, Pt, Au, Hg, Ge, or Sb, or the flux may filed on Mar.
    [Show full text]
  • Ultra-Thin Niobium Nitride Films for Hot Electron Bolometer and Thz Applications
    THESIS FOR THE DEGREE OF LICENTIATE OF ENGINEERING Ultra-thin Niobium Nitride Films for Hot Electron Bolometer and THz Applications SASCHA KRAUSE Group for Advanced Receiver Development Department of Earth and Space Science CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden 2016 i Ultra-thin Niobium Nitride Films for Hot Electron Bolometer and THz Applications SASCHA KRAUSE © SASCHA KRAUSE, 2016. Thesis for the degree of Licentiate of Engineering Group for Advanced Receiver Development Department of Earth and Space Science Chalmers University of Technology SE-412 96 Gothenburg Sweden Telephone + 46 (0)31-772 1000 Cover: Upper left corner: The Atacama Path Finder Experiment representing the exploration of space in the submillimeter and THz frequency range, upper right corner: HRTEM image of ultra-thin NbN film that is grown onto a GaN buffer-layer in an epitaxial manner, lower left corner: SEM image of the employed HEB used for measuring the phonon escape time, lower right corner: Resistance versus temperature behavior of the investigated ultra-thin NbN films which were grown onto different buffer-layers and substrates. [Printed by Chalmers Repro Service] Gothenburg, 2016 ii Ultra-thin Niobium Nitride Films for Hot Electron Bolometer and THz Applications SASCHA KRAUSE Group for Advanced Receiver Development Department of Earth and Space Science Chalmers University of Technology Gothenburg, Sweden 2016 Abstract The part of the electromagnetic spectrum between microwaves and infrared, also known as the terahertz band, is of particular interest for radio astronomy. The radiation intensity of the cold universe peaks at this frequency band, thus defining the demand on sensitive low-noise instruments in this particular frequency range.
    [Show full text]
  • Development of a Nbn Deposition Process for Superconducting Quantum Sensors
    1 Development of a NbN Deposition Process for Superconducting Quantum Sensors D. M. Glowacka, D. J. Goldie, S. Withington, H. Muhammad, G. Yassin , and B. K. Tan occurs with the addition of the reactive gas during sputtering, Abstract— We have carried out a detailed programme to which in turn affects stoichiometry. It is very important to explore the superconducting characteristics of reactive DC- quantify the location of the best operating point, and this magnetron sputtered NbN. The basic principle is to ignite a requires a careful study of the effects of deposition conditions. plasma using argon, and then to introduce a small additional Thakoor et al. [2] found that high-Tc NbN films were nitrogen flow to achieve the nitridation of a Nb target. Subsequent sputtering leads to the deposition of NbN onto the deposited at the point where the total sputter pressure started host substrate. The characteristics of a sputtered film depend on to increase rapidly with increasing nitrogen flow. In this paper, a number of parameters: argon pressure, nitrogen flow rate and we outline work that we have done to create a high-yield time-evolution profile, substrate material, etc. Crucially, the highly-reproducible deposition process for high-Tc NbN. We hysteresis in the target voltage as a function of the nitrogen flow also briefly describe work on realising and measuring can be used to provide a highly effective monitor of nitrogen resonators of the kind that would be suitable for a KID array consumption during the reactive process. By studying these dependencies we have been able to achieve highly reproducible operating at 3.5 K in an easy-to-use closed-cycle refrigerator.
    [Show full text]
  • Enhancement of the Corrosion Resistance of 304 Stainless Steel by Cr–N and Cr(N,O) Coatings
    Article Enhancement of the Corrosion Resistance of 304 Stainless Steel by Cr–N and Cr(N,O) Coatings Mihaela Dinu 1, Emile S. Massima Mouele 2, Anca C. Parau 1, Alina Vladescu 1,3, Leslie F. Petrik 2 and Mariana Braic 1,* 1 National Institute for Optoelectronics, 409 Atomistilor St., 077125 Magurele, Romania; [email protected] (M.D.); [email protected] (A.C.P.); [email protected] (A.V.) 2 Department of Chemistry, Environmental and Nano Sciences, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa; [email protected] (E.S.M.M.); [email protected] (L.F.P.) 3 National Research Tomsk Polytechnic University, Lenin Avenue 43, Tomsk 634050, Russia * Correspondence: [email protected]; Tel.: +4-21-457-57-59 Received: 27 February 2018; Accepted: 2 April 2018; Published: 5 April 2018 Abstract: Chromium nitride and oxynitride coatings were deposited as monolayers ((Cr–N), Cr(N,O)) and bilayers (Cr–N/Cr(N,O), Cr(N,O)/Cr–N) on 304 steel substrates by reactive cathodic arc method. The coatings were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), surface profilometry, and scratch tester. The anticorrosive properties of the coatings were assessed by electrochemical tests in 0.10 M NaCl + 1.96 M H2O2, carried out at 24 °C. Cr2N, CrN, and Cr(N,O) phases were identified in the coatings by grazing incidence X-ray diffraction (GI-XRD) measurements. The measured adhesion values ranged from 19 N to 35 N, the highest value being obtained for the bilayer with Cr(N,O) on top.
    [Show full text]
  • Evaluation of Anticorrosive Effect of Niobium Carbide Coating
    1387 A publication of CHEMICAL ENGINEERING TRANSACTIONS VOL. 57, 2017 The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Sauro Pierucci, Jiří Jaromír Klemeš, Laura Piazza, Serafim Bakalis Copyright © 2017, AIDIC Servizi S.r.l. DOI: 10.3303/CET1757232 ISBN 978-88-95608- 48-8; ISSN 2283-9216 Evaluation of Anticorrosive Effect of Niobium Carbide Coating Applied on Carbon Steel b a b a Luisa Novoa , Luis E. Cortes , Eliana Gonzalez , Arnaldo Jimenez , Luis G. a a a Cortes , Mario Ojeda , Aida L. Barbosa* a Laboratory of Research of Catalysis and New materials (LICATUC), Science Faculty, Chemistry Program, University of Cartagena, Campus of Zaragocilla, Kra 50 Nº 30-40, Cartagena, Colombia b Dept of Civil Engineering, Civil Enginering programm, University of Cartagena, Campus of Piedra de Bolivar, Av. El Consulado Calle 30. No. 48 - 152, Cartagena, Colombia [email protected] South America and particularly Colombia, has niobium and tantalum deposits, which can be used as a carbon steel protective agent. A preliminary step is the raw material characterization. Fresh and calcinated samples of niobium mineral in ores and sand were analyzed through optic microscopy, laser-Raman spectroscopy, DRX and textural aspects. The main components of the ore and alluvial sand were Ferrotapiolite and ferrocolumbite with chemical formula (Fe,Mn)•(Ta,Nb)2O6 and associated oxides like Fe2O3, SiO2. In the shape of Tectosilicates, Mn-Tantalite, Nb=O terminal and polyatomic octahedral structures of NbO6, highly distorted, susceptible to form carbides. Ferrocolumbite synthetic (FeNb50) was used as precursor of NbC coating for the surfaces protection of AISI 1020 steel samples having dimensions of 3/8 inch diameter and 1/2 inch length.
    [Show full text]
  • Technology Properties and Applications of Niobium Carbide
    Fundame slatn and Applications of Mo and Nb Alloying in High Performance sleetS – Volume 2 Edited by Hardy Mohrb ehca r CBMM, IMOA and TMS, 2015 TECHNOLOGY, PROPERTIES AND APPLICATIONS OF NIOBIUM CARBIDE REINFORCED STEEL AND IRON ALLOYS H. Mohrb ca h re 1 a dn D . Jar er at 2 1 NiobelCon bvba, Schild ,e B le gium 2 Metal Prime T ce olonh gy .etP L ,.dt niS g pa ore Keywords: Abrasive eW ,ra Wear Resistant Steels, NbC Particles, W etih C tsa I nor s Abstract The al rge tsoc dna snoc i elbared downtime uac es d by lper a ic ng wo nr rap ts ni htrae moving na d mining equipment, sa well sa ni eht materials issecorp ng tsudni ry, er stneserp a uounitnoc s ellahc nge ot materi la poleved men .t Components sed ig den rof sacri cif i la wear must ni ht e tsrif ecalp ssessop tauqeda e a noisarb natsiser c .e F qer u tne ly, oh wev ,re ht ey must osla evah ht e iliba ty ot dnatshtiw impact dna to tsiser chemical .kcatta The eriuqer m tne fo good noisarba r ecnatsise in combination htiw g oo d uot g ssenh si g ne e lar ly ni .noitcidartnoc Typi lac ly, rah d ori n- esab d materials hcus sa marten etis ro etirubedel era hi hg ly tnatsiser ot ba r isa on, y te very elttirb dna tluciffid ot machine. An evitavonni rppa o hca si ot compose a more cud tile ori n-b desa m irta x, embedding a much ah r red we ra tnatsiser phas .e Amongst esoht ex rt emely ha dr ahp s se are sedibrac of eht tr noitisna metals uinatit m, oin b ui m, dna ut ng ets n tiw h hardn sse fo vo er 002 0 HV.
    [Show full text]
  • Crystal Structure of Hexabarium Mononitride Pentaindide,(Ba6n)[In5]
    Z. Kristallogr. NCS 219 (2004) 349-350 349 © by Oldenbourg Wissenschaftsverlag, München Crystal structure of hexabarium mononitride pentaindide, (Ba6N)[In5] A. Schlechte, Yu. Prots and R. Niewa* Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, 01187 Dresden, Germany Received October 1, 2004, accepted and available on-line November 12, 2004; CSD no. 409805 Discussion Indium, when combined with alkaline-earth elements forms a va- riety of ternary nitrides. The compounds known so far may be de- scribed as built from indium clusters and octahedra of alkaline- earth cations surrounding nitride ions. In the latter cationic sub- structure the polyhedra might be isolated, vertex-, and/or edge- sharing. The variety of In arrangements extends from isolated In species in (Ca7N4)Ini.o4 [1], isolated tetrahedral units in (AI9N7)[ID4]2 (A = Ca, Sr, Ba) [2,3], trigonal bipyramidal [Ins] clusters next to [Ins] ions of more complicated geometry in (Ba38Ni8)[In5]2[In8] [4], and infinite chains in (A4N)[In2] (A = Ca, Sr) [5] and (Ca2N)In [6]. None of these metallic compounds follows Zintl-like counting. The new compound (Ba6N)[Ins] is an isotype of (¿6N)[Ga5] (A = Sr, Ba) [7]. The crystal structure of (Ba6N)tIns] is characterized as rocksalt type motif of N-centred octahedra (BaiN) and trigonal bi- pyramidal clusters [Ins]. The trigonal bipyramidal units [Ins] might be described as [Ins]7- ions, quite the same according to Zintl-type electronic counting and using the Wade-rules for closo-cluster. The isotypes (AeN)[Gas] were previously de- scribed by the formula (A2+)6(N3-)[Ga5]7~ • 2e_ based on elec- tronic structure calculations.
    [Show full text]