Thermodynamic modeling of the Au-Sb-Si ternary system

Research highlights: → Thermodynamic optimization of the Au-Sb binary system was updated. → The Si-Sb binary system was assessed from critical review of experimental information. → Thermodynamic modeling of the Au-Sb-Si ternary system was performed. → The phase relations of this ternary system are useful to design Au-based solders. - Abstract: Thermodynamic optimization of the Au-Sb binary system was updated as well as the Si-Sb binary system was assessed thermodynamically using the CALPHAD method based on the critical review of the available experimental information from the published literature. The solution phases including liquid, fccA1(Au), diamondA4(Si) and rhombohedralA7(Sb), are modeled as substitutional solutions and their excess Gibbs energies are expressed by a Redlich-Kister polynomial. The solubility of Si in the intermetallic compound AuSb2 is not taken into account because of the lack of experimental information. Combined with previous assessment of the Au-Si binary system, thermodynamic modeling of the Au-Sb-Si ternary system was performed to reproduce well the measured phase equilibria. The liquidus projection and several vertical sections of this ternary system were calculated, which are in reasonable agreement with the reported experimental data.