The character of chemical interaction of Pb₂Ga₂S₅ and YbGa₂S₄ compounds was studied and the T-x phase diagram of the Pb₂Ga₂S₅-YbGa₂S₄ system was constructed using the methods of physicochemical analysis: differential thermal analysis (DTA), X-ray phase analysis (XRD), microstructural analysis (MSA), as well as methods for determining microhardness and density. It was found that the Pb₂Ga₂S₅-YbGa₂S₄ system is a quasi-binary section of the quasi-ternary  PbS-Ga₂S₃-YbS system and belongs to the eutectic type. The composition of the eutectic formed between the Pb₂Ga₂S₅ and YbGa₂S₄ compounds is 30 mol. % YbGa₂S₄, the temperature is 625°C. A wide region of solid solution based on both components at room temperature was found in the Pb₂Ga₂S₅-YbGa₂S₄ system. It was found that at room temperature in the system based on the Pb₂Ga₂S₅ compound the solubility reaches 12 mol. % YbGa₂S₄, and in the system based on the YbGa₂S₄ compound - 18 mol. % Pb₂Ga₂S₅. X-ray structural analysis of solid solution alloys (YbGa₂S₄)_1-x(Pb₂Ga₂S₅)_x (x=0.03; 0.05; 0.10) was carried out and their lattice parameters were calculated. The temperature dependence of electrical conductivity and thermo-EMF of solid solution alloys ((YbGa₂S₄)_1-x(Pb₂Ga₂S₅)_x (x=0.01; 0.03; 0.04; 0.05) formed in the system was studied. Solid solution alloys are semiconductor materials with high resistance.

doi.org/10.32737/0005-2531-2025-3-81-89