Phase Equilibria of Sn-Sb-Ag Ternary System (II): Calculation

Knowledge of the phase equilibria of the Sn-Sb-Ag ternary system is of fundamental importance in Sn-Sb–based solder applications. Thermodynamic models of the ternary Sn-Sb-Ag system and the binary Sb-Ag and Sn-Ag systems are developed using the calculation of phase diagrams (CALPHAD) method. The calculated 250 °C isothermal section, liquidus projection, and thermodynamic properties are in good agreement with the experimental results. There are two continuous solid solutions formed between the ε-Ag3Sn and ε-Ag3Sb, and ζ-Ag17Sb3 and ζ-Ag5Sn phases, but there is no ternary compound. There are three class II ternary invariant reactions, L + Sb ↔ ε + β-SnSb, L + β-SnSb ↔ Sn3Sb2 + ε, and L + Sn3Sb2 ↔ Sn + ε. Their reaction temperatures are 379 °C, 313 °C, and 231 °C, respectively.