Ag2Se–SiSe2–SnSe2 System: Experimental Study and 3D Visualization of the Phase Diagram

The results of an experimental study and analytical 3D visualization of phase equilibria in the Ag2Se–SiSe2–SnSe2 (A) system are presented. The Т–х diagram of the SiSe2–SnSe2 boundary system; selected polytherms and 300, 800, 900, and 1000 K isotherms of the phase diagram; and the liquidus surface projection of system (A) are constructed. The SiSe2–SnSe2 boundary system is found to be quasi-binary and eutectic-type. System (A) is a quasi-ternary section of the Ag–Si–Sn–Se tetrahedron. Its liquidus surface is comprised of four fields corresponding to the primary crystallization of SiSe2, SnSe2, and HT-Ag2Se based phases and a continuous series of high-temperature solid solutions along the Ag8SiSe6–Ag8SnSe6 section. The subsolidus phase transformations of system (A) are associated with the polymorphism of Ag2Se, Ag8SiSe6, Ag8SnSe6, and their based solid solutions. The phase diagrams of boundary quasi-binary systems and a limited amount of DTA data for samples of system (A) served to derive equations for the calculation and 3D modeling of the liquidus surfaces of phases, and their visualization was carried out.