The Influence of Inculcational and Substitutional Impurities on the Electronic Properties of Transition Metal Refractory Carbides and Nitrides and Their Solid Solutions

Ivanovskiĭ, A. L.; Швейкин, Г. П.

doi:10.1002/pssb.2221810202

Cited by 15 publications

(3 citation statements)

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“…This fact corresponds to lowering E coh in the series 14 of hexagonal Ti 3 AlC 2 ® 'Ti 3 AlN 2 ' and can be related to weakening the covalent bonds Ti(1,2)-N in comparison with Ti(1,2)-C, as it was found for 'pure' binary cubic (B1) TiC and TiN. 19 Let us consider the nature of chemical bonding in Ti 3 AlC 2 and Ti 3 AlN 2 in greater detail. As follows from the present calculations, the chemical bonding in these phases is of a complex combined ionic-covalent-metallic type.…”

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confidence: 74%

“…This fact is indicative of the formation of local hybrid bonds Ti(2)-C inside the 'carbide' layer, as it takes place in binary cubic carbides. 19 The LDOS of Ti(1) has a more complicated shape and reflects both the formation of the covalent bonds Ti(1)-C inside the octahedra and the 'interlayer' interaction Ti(1)-Al. As follows from the analysis performed, the covalent bonds C-Ti(1)-Al (along the c axis, Figure 1) are considerably weaker than the C-Ti(2)-C bonds.…”

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confidence: 99%

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Electronic structure of hexagonal Ti3AlC2 and Ti3AlN2

Ivanovskiĭ

Medvedeva

1999

Mendeleev Communications

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confidence: 74%

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confidence: 99%

Electronic structure of hexagonal Ti3AlC2 and Ti3AlN2

Ivanovskiĭ

Medvedeva

1999

Mendeleev Communications

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“…Except Si, these elements have similar atomic size with C, which allows substitution for C in the interstitial sites of the metal lattice. For example, the group-4 TMCs can form a full-range solid solution with N in the NaCl-type structure, and solid solutions with B and O with a much narrower solution-range due to the lack of isostructural phases in M-B and M-O systems (M = Ti, Zr, and Hf) [99][100][101]. Many studies on TMC solid-solutions on their C sites are regarding with improving properties for cemented carbides, such as a higher hardness and improved oxidation-resistance of Ti(C,N) than TiC alone [99,100].…”

Section: Ternary Transition-metal Carbidesmentioning

confidence: 99%

Phase Formation of Nanolaminated Transition Metal Carbide Thin Films

Lai¹

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The cover image is a simple sketch of structural-chemical relation in between the metal layers in nanolaminated transition metal carbides: Mo2GaC, Mo2Ga2C, and Mo2(Au1-xGax)2C with an in-plane order in the Au-Ga layers, where the last two phases were discovered in this thesis. © Chung-Chuan Lai 2017Printed in Sweden by LiU-Tryck 2017 ISSN 0345-7524 ISBN 978-91-7685-526-3 i AbstractResearch on inherently nanolaminated transition metal carbides is inspired by their unique properties combining metals and ceramics, such as higher damage tolerance, better machinability and lower brittleness compared to the binary counterparts, yet retaining the metallic conductivity. The interesting properties are related to their laminated structure, composed of transition-metal carbide layers interleaved by non-transition-metal (carbide) layers. These materials in thin-film form are particularly interesting for potential applications such as protective coatings and electrical contacts. The goal of this work is to explore nanolaminated transition metal carbides from the aspects of phase formation and crystal growth during thin-film synthesis. This was realized by studying phases in select material systems synthesized from two major approaches, namely, from direct-deposition and post-deposition treatment.The first approach was used in studies on the Mo-Ga-C and Zr-Al-C systems. In the former system, intriguing properties have been predicted for the 3D phases and their 2D derivatives (so called MXenes), while in the latter system, the phases are interesting for nuclear applications.In this work, the discovery of a new Mo-based nanolaminated ternary carbide, Mo2Ga2C, is evidenced from thin-film and bulk processes. Its structure was determined using theoretical and experimental techniques, showing that Mo2Ga2C has Ga double-layers in simple hexagonal stacking between adjacent Mo2C layers, and therefore is structurally very similar to Mo2GaC, except for the additional Ga layers. For the Zr-Al-C system, the optimization of phase composition and structure of Zr2Al3C4 in a thin-film deposition process was studied by evaluating the effect of deposition parameters. I concluded that the formation of Zr2Al3C4 is favored with a plasma flux overstoichiometric in Al, and with a minimum lattice-mismatch to the substrates. Consequently, epitaxial Zr2Al3C4 thin film of high quality were deposited on 4H-SiC(001) substrates at 800 °C.With the approach of post-deposition treatment, the studies were focused on a new method of thermally-induced selective substitution reaction of Au for the non-transition-metal layers in nanolaminated carbides. Here, the reaction mechanism has been explored in Al-containing (Ti2AlC and Ti3AlC2) and Ga-containing (Mo2GaC and Mo2Ga2C) phases. The Al and Ga in ii these phases were selectively replaced by Au while the carbide layers remained intact, resulting in the formation of new layered phases, Ti2Au2C, Ti3Au2C2, Mo2AuC, and Mo2(Au1-xGax)2C, respectively. The substitution reaction was explained by fast outward diffus...

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