The mixed intermetallic silicide Nb5-xTaxSi3 ( 0 ≤ x ≤ 5). Crystal and electronic structure

JOURNAL OF ALLOYS AND COMPOUNDS

卷:584

Article

Tillard, Monique

关键词: High-temperature alloys;    Transition metal alloys and compounds;    Crystal structure;    X-ray diffraction;    Electronic band structure;    Enthalpy;   

DOI  :  10.1016/j.jallcom.2013.09.078

来源: Elsevier

【 摘 要 】

Intermetallic transition metals silicides are of particular interest because of their specific properties such as high melting point, oxidation resistance, creep resistance and toughness. Single crystals have been obtained for both low and high temperature polymorphs of the compound Nb5 xTaxSi3 (0 <= x <= 5). Although different, their X-ray structures are both solved and refined in the tetragonal I4/mcm space group. The low temperature polymorph belongs to the Cr5B3 structural type (a = 6.5262 angstrom and c = 11.866 angstrom for composition Nb3.9Ta16.1Si12) while the high temperature polymorph adopts the W5Si3 structural type (a = 9.9870 angstrom and c = 5.0794 angstrom at composition Nb10.3Ta9.7Si12). Structure stability and bonding within the mixed compound Nb-5 xTaxSi3 are analyzed comparatively with Nb5Si3 and Ta5Si3 parents, by means of DFT calculations. (c) 2013 Elsevier B.V. All rights reserved.

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