Thermodynamic properties and melting behavior of Bi-Sn-Zn alloys

The partial and integral enthalpies of mixing of liquid Bi-Sn-Zn alloys were determined at 500øC by a drop calorimetric technique using a Calvet-type microcalorimeter. The ternary interaction parameters in the Bi-Sn-Zn system were fitted using the Redlich-Kister-Muggianu model for substitutional solutions, and isoenthalpy curves of the integral molar enthalpy of mixing at 500øC were constructed. Furthermore, a DSC technique was used to determine the liquidus temperatures in three sections (3, 5, and 7 at.% Zn) as well as the invariant reaction temperature of the ternary eutectic L ⇄ (Bi) + (Sn) + (Zn). The ternary eutectic reaction was found at 135ø