Theoretical investigation of the thermodynamic activities of Zn-In-Sn lead-free solder alloys and the concerned binary alloys

Thermodynamic activities of the components for the binary lead-free solder alloys, such as In-Zn at 700 K, In-Sn at 700 K, and Sn-Zn at 750 K, have been calculated using the molecular interaction volume model (MIVM). The theoretical data have been compared with the corresponding experimental values. For the validity of the model parameters, the excess Gibbs free energy of mixing of In-Zn, In-Sn, and Sn-Zn liquid alloys have been determined and compared with the corresponding experimental data available in the literature. A good agreement has been observed between the theory and experiment. Further, the estimated model parameters have been utilized to calculate the activity of Zn in Zn-In-Sn ternary lead-free solder alloys at 813 K. The theoretical values and the experimental values for the activity of Zn in Zn-In-Sn ternary liquid alloys at 813 K are in good agreement.