Phase equilibria of binary Ag–Se and ternary Ag–Pb–Se systems

Ag–Se and Ag–Pb–Se are important material systems for thermoelectric applications, yet their phase equilibria and thermodynamic descriptions have not been studied extensively. This study experimentally determines the phase equilibria of isothermal sections at 550°C and 400°C. No ternary compound is found, and the third element's solubility in the binary compounds is negligible. The Ag–Se binary system is thermodynamically modeled using the Calphad method. Based on the experimental results in this work and those from the literature review. This study proposes the thermodynamic descriptions of the Ag–Pb–Se ternary system using the Calphad method for the first time. The isothermal sections, isopleth sections, and liquidus projection were calculated and compared with the experimental data, showing good agreement between the experimental results and thermodynamic calculation.