PHASE EQUILIBRIA IN THE SECTION Cu2Se – Cu3SbSe4

Complex selenides are promising thermoelectric materials in a wide temperature range. Since one of the methods for improving material parameters is the formation of solid solutions, the study of phase equilibria and the determination of the homogeneity regions of the components is relevant. This paper presents the results of a study of the physico-chemical interaction in the CuSe2 – Cu3SbSe4 system. The synthesis of alloys of the CuSe2 – Cu3SbSe4 system (0; 10; 30; 50% 70; 90; 100 mol. % Cu3SbSe4) was carried out by a direct one-temperature method at a maximum synthesis temperature of 1053 K. The obtained alloys were studied by X-ray phase, differential thermal and microstructural analyses. Based on the results of the analyses, it was found that CuSe2 – Cu3SbSe4 system is a partially quasi-binary section of the quasi-ternary Cu2Se–Sb2Se3–Se system. The section of CuSe2 – Cu3SbSe4 is characterized by the passage of four nonvariant processes. The studied section crosses the region of primary crystallization of the phase with congruent melting character - β-Cu2Se and the miscibility gap in liquid phase. The region of boundary solid solutions based on the initial components CuSe2 and Cu3SbSe4 does not exceed 5 mol.%. Keywords: selenides; phase diagram; thermal analysis; phase equilibria.