N 21 Nanostructure of Dispersed and Compact Nonstoichiometric Vanadium Carbide / A. I. Gusev, A. A. Tulin, V. N. Lipatnikov, A. A. Rempel // Russian Journal of General Chemistry. - 2002. - Vol. 72, № 7. - P997-1006 : il. - Bibliogr. : p. 1005-1006 (21 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НАНОСТРУКТУРА -- НЕСТЕХИОМЕТРИЯ -- КАРБИД ВАНАДИЯ Аннотация: Structure and properties of dispersed and compact nanocrystalline vanadium carbide VC0.875 were studied. Dispersed vanadium nanocarbide was prepared by prolonged aging of a coarse-grained VC0.875 powder. It has a unique nanostructure: nanocrystallites of dispersed vanadium carbide have a shape of bent lobes up to 600 nm in diameter and 15320 nm thick. Annealing and quenching of compact samples of coarsegrained VC0.875 carbide result in the formation of a nanodomain structure. The nanostructured carbide VC0.875 corresponds in composition to the higher boundary of a homogeneity area of a cubic phase and mainly contains ordered V8C7 phase, which belongs to the P4332 space group. Cold pressing and subsequent vacuum sintering of vanadium carbide nanopowder at 2000 K gave sintered samples approaching diamond in microhardness. Полный текст |