G 96 Gusev, A. I. Ordering in the zeta-Ta4C3 – x Carbide Phase [Text] / A. I. Gusev, V. N. Lipatnikov // JETP Letters. - 2005. - Vol. 82, № 5. - P287-291 : il. - Bibliogr. : p. 291 (14 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): НЕСТЕХИОМЕТРИЯ -- КАРБИД ТАНТАЛА Аннотация: The structure of the zeta-Ta4C3 – x nonstoichiometric trigonal (rhombohedral) carbide, which is formed in the tantalum–carbon system, has been analyzed by neutron diffraction, x-ray diffraction, and metallography. The ordered distributions of carbon atoms and structure vacancies have been experimentally determined and the distribution function of carbon atoms over the nonmetallic-sublattice sites, where ordering occurs, has been calculated. The parameters of the unit cell of the zeta-Ta4C3 – x (TaC0.67) trigonal (space group ) carbide are found to be aH = 0.3123 nm and cH = 3.0053 nm. It has been shown that the metallic close packed sublattice of the ??zeta-Ta4C3 – x carbide is formed by alternating blocks, where metal atoms are located both in the fcc and hcp sublattices of the TaCy cubic and Ta2C hexagonal carbides, respectively Полный текст |