Thermodynamic assessment of Au–Pt system

Abstract

The thermodynamic re-assessment of Au–Pt binary system was carried out by using the Calphad method and based on the recent experimental data. The Gibbs energies of face-centred cubic and liquid phases were described by a sub-regular solution model with the Redlich-Kister equation. Much effort was taken to reproduce the phase equilibrium results and thermodynamic properties of the solid phase, including the activity and mixing enthalpy. The constraint of the third law of thermodynamics was also considered in the assessment. According to the presently assessed results, the miscibility gap region in the Au–Pt system slightly shifts to the Au-rich side, and the critical point of the miscibility gap is about 1200 °C and Au–56% Pt.