Pressure effect on ternary phase diagrams: Bi-Sb-Pb as a case study

Abstract

Pressure can affect phase diagrams significantly, as previously demonstrated on several binary systems. However, the effect of pressure on ternary phase diagrams is mostly unexplored. In this study, a thermodynamic model of a ternary phase diagram under high pressure is formulated and applied to calculate the Bi-Sb-Pb system. The model employs binary interaction parameters and elemental thermodynamic functions to which the effect of pressure on the binary interaction parameters and elemental properties are added. The complete ternary Bi-Sb-Pb phase diagram was calculated up to a pressure of 2 GPa at selected temperatures as a case study, as this system involves three different types of binary phase diagrams: isomorphous, eutectic, and peritectic. The results show how pressure affects the stability of solid phases, leading to changes in the three-phase triangles and the four-phase equilibrium quadrilateral. This study provides insights into the pressure-dependent behavior of ternary systems and contributes to the thermodynamic understanding of ternary phase diagrams under high-pressure conditions.