Synthesis homogeneity estimation for highly nonstoichiometric disordered and ordered carbides

One studied the peculiarities of solid-phase synthesis of highly nonstoichiometric carbides with the controlled concentration of structure vacancies in carbon sublattice. Four basic stages of synthesis of nonstoichiometric carbides were determined by means of solid-phase caking. Inhomogeneity of highly nonstoichiometric compounds was shown to result in amplification of diffraction reflections. The functional ratio between the amplification and inhomogeneity was determined for the first time and a method based on the diffraction measurements for the qualitative evaluation of homogeneity level of the nonstoichiometric compounds was presented. The findings are illustrated by the rating of homogeneity level of niobium nonstoichiometric carbide on the basis of the experimental data on the width of X-ray diffraction reflections. Conditions of thermal treatment ensuring preparation of nonstoichiometric carbides of 4 and 5 groups transition metals in disordered and ordered states were determined