R 42 Rempel, A. A. Nanostructure and atomic ordering in vanadium carbide / A. A. Rempel, A. I. Gusev // Journal of Experimental and Theoretical Physics. - 1999. - Vol. 69, № 6. - P. 472-478 : il. - Bibliogr. : p. 478 (12 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): КАРБИД ВАНАДИЯ -- НАНОСТРУКТУРА Аннотация: Nanostructured nonstoichiometric vanadium carbide VC0.87 was obtained in powdered form using the ordering effect. The composition, structure, and properties of the carbide were studied by chemical and thermogravimetric analysis, gas chromatography, x-ray diffraction, optical and electronic microscopy, electron–positron annihilation, magnetic susceptibility, and microhardness methods. Nanostructured vanadium carbide VC0.87 possesses the crystal structure of the cubic ordered phase V8C7 with space group P4332. Vanadium carbide nanocrystallites are shaped in the form of 400–600 nm in diameter and 15–20 nm thick curved petals. The surface layer of the nanocrystallites contains defects of the vacancy agglomerate type. The microhardness of vanadium carbide, obtained by vacuum sintering of VC0.87 nanopowder was 60–80 GPa, which is 3–4 times greater than the microhardness of coarse-grained vanadium carbide with the same composition and close to the hardness of diamond |