Phase equilibria in the Ag2Se-AgAsSe2-AgBiSe2 system

Abstract

Phase equilibria in the pseudoternary system Ag2Se-AgAsSe2-AgBiSe2 have been studied using differential thermal analysis, X-ray diffraction, microhardness tests, and emf measurements on silver concentration cells with Ag4RbI5 as solid electrolyte. The results are used to construct the 300-, 600-, and 800-K isothermal sections, a number of partial phase diagrams, and the liquidus projection. Several in- and univariant peritectic and eutectic equilibria and a broad region of AgBiSe2-based solid solutions are identified. The homogeneity range of the high-temperature phase of AgBiSe2 reaches −50 mol % in width (650 K), and that of the low-temperature phase is 20 mol % in width (300 K) along the AgAsSe2-AgBiSe2 constituent binary. The melting points, lattice parameters, and microhardness of the solid solutions are determined.