Phase equilibria in the Cu2SnSe3–Sb2Se3–Se system

Abstract

Complex copper-tin and copper-antimony chalcogenides are of great interest for the development of new environmentally friendly and inexpensive thermoelectric materials. Recently, these compounds have been drawing more interest due to the possibility of increasing their thermoelectric performance with various cationic and anionic substitutions. In this article, we continued the study of multi-component systems based on the copper chalcogenides and presented the results of the study of phase equilibria in the Cu2SnSe3–Sb2Se3–Se system. The study was conducted using differential thermal analysis and powder X-ray diffraction. Based on the experimental data, a projection of the liquidus surface and three polythermal cross sections of the phase diagram were plotted. We determined the regions of primary crystallisation of the phases and the nature and temperatures of non-variant and monovariant equilibria. It was established that the liquidus surface consisted of two primary crystallisation regions based on Cu2SnSe3 and Sb2Se3 phases. The primary crystallisation region of elementary selenium was degenerate. A large immiscibility region of two liquid phases was found in the system.