Through experimental study of carefully crystallized via long-term thermal annealing alloys using powder X-ray diffraction and differential thermal analysis methods, as well as considering the evidence from the literature, a comprehensive picture of phase equilibria in the Cu₂Se-Cu₃AsSe₄-As₂Se₃ system was obtained. The projection of the liquidus surface, the isothermal section at 500 K, and three vertical sections of the phase diagram are presented and discussed. The fields of primary crystallization of phases, types, and coordinates of invariant and monovariant phase equilibria are determined. The side Cu₂Se-As₂Se₃ system was re-investigated and its refined phase diagram was constructed. It is shown that this system is quasi-binary and is characterized by the formation of ternary Cu₃AsSe₃ and CuAsSe₂ compounds.

doi.org/10.32737/0005-2531-2024-3-83-93