Thermodynamic description of the Cu–Sb binary system

The Cu–Sb binary system can be important for various applications, especially for electronic products as a part of lead-free soldering technology. It was found that δ and η phases have been frequently encountered in the electronic products. However, the two phases have been described as line compounds in the previous thermodynamic modeling, and their compositional homogeneities were not considered. Moreover, the γ phase has been described as BCC_A2 and this kind of description makes big problem for extension of calculations to some higher order systems. In this study, the thermodynamic properties of the Cu–Sb binary system were modeled and the phase diagram was calculated by the CALPHAD method, using experimental information reported in the literature. The δ phase was described using compound energy model with two sublattices. In this way the compositional homogeneity could be calculated. Good agreement was found between the calculated results and the existing experimental data.