ESTIMATION OF Sn Activity In Ternary Lead-Free Sn-Ag-Au ALLOYS AND ITS SUBSYSTEMS

Abstract

The activities of components in the binary liquid Ag-Sn, Au-Sn and Ag-Au alloys were calculated using the molecular interaction volume model (MIVM) at 1250 K, 823 K and 800 K, respectively. The reasonable good agreement between the calculated and the corresponding experimental data for the constituents binary alloy form the basis of employing the MIVM to predict the activities of Sn in ternary liquid Sn-Ag-Au alloys at different temperatures of 973 K, 1073 K, 1173 K, 1273 K and 1373 K with a constant molar ratio of Ag:Au = 1:2, 2:2 and 2:1 across the three sections, respectively. The activity of tin in Sn-Ag-Au alloys was found to show a negative deviation from ideality across the entire concentration range. The calculated values of the tin activities compared quite well with the corresponding experimental values.