A physicochemical study of the Sb2Se3–Nd2Se3 system

Abstract

We have studied phase relations in the Sb₂Se₃–Nd₂Se₃ system and mapped out its T–x phase diagram using differential thermal analysis, X-ray diffraction, microstructural analysis, microhardness tests, and density measurements. The system contains one compound, with the composition NdSbSe₃, which melts incongruently at 865 K and crystallizes in orthorhombic symmetry with the following lattice parameters: а = 12.77(1) Å, b = 14.08(1) Å, and c = 5.82(5) Å (Z = 8, ρ_meas = 6.20 g/cm³, ρ_x = 6.38 g/cm³). At room temperature, the Nd₂Se₃ solubility in Sb₂Se₃ is 5 mol % and the Sb₂Se₃ solubility in Nd₂Se₃ is 2.5 mol %. The Sb₂Se₃–Nd₂Se₃ system has a eutectic located at 15 mol % Nd₂Se₃, with a melting point at 755 K. The electrical conductivity and thermoelectric power of the (Sb₂Se₃)_1–x(Nd₂Se₃)_x solid solutions have been measured as functions of temperature.