Thermodynamic re-optimisation of the Bi–In–Sn system based on new experimental data

The temperature of phase transformations, as well as the enthalpy of melting of 29 different alloys from the Bi–In–Sn system were measured by DSC using a Perkin–Elmer DSC-7 instrument. The following tie-triangles were characterized in terms of analysing the chemical composition of the phases in equilibrium, using energy dispersive X-ray analysis (EDX): (Bi)–BiIn–(Sn) at 77 °C, BiIn2-β-γ at 59 °C including the composition of the liquid phase at 59 °C and the tie-line BiIn2-γ at 59 °C.A new thermodynamic description is presented for the ternary Bi–In–Sn system in the entire composition range. The parameters for the thermodynamic models of the constituent binary systems Bi–In, Bi–Sn and In–Sn are adopted from earlier assessments, and those for the Bi–In–Sn system are optimized in this study using experimental data on phase equilibria and data on the enthalpy of melting of different alloys available in the literature and measured in the present work. Several vertical and isothermal sections as well as the liquidus surface and selected thermodynamic properties are calculated using the thermodynamic description. They show reasonably good agreement with reported experimental data.