New Solid Solution and Phase Equilibria in the Subsolidus Area of the Three-Component CuO-VO-TaO Oxide System.

The results of the study of the three-component system of CuO-VO-TaO oxides showed, inter alia, that in the air atmosphere in one of its cross-sections, i.e., in the CuVO-CuTaO system, a new substitutional solid solution with the general formula CuTaVO and homogeneity range for x > 0.0 and x ≤ 0.3 is formed. The influence of the degree of incorporation of V ions into the CuTaO crystal lattice in place of Ta ions on the unit cell volume, thermal stability and IR spectra of the obtained solid solution was determined. Moreover, the value of the band gap energy of the CuTaVO solid solution was estimated in the range of 0.0 < x ≤ 0.3, and on this basis, the new solid solution was classified as a semiconductor. On the basis of the research results, the studied system of CuO-VO-TaO oxides was also divided into 12 subsidiary subsystems.