Enthalpies of mixing of liquid systems for lead free soldering: Co-Sb-Sn

The partial and integral enthalpy of mixing of molten ternary Co-Sb-Sn alloys was determined performing high temperature drop calorimetry in a large compositional range at 1273 K. Measurements have been done along five sections, x(Sb)/x(Sn) approximate to 1:1, x(Sb)/x(Sn) approximate to 1:3, x(Sb)/x(Sn) approximate to 3:1, x(Co)/x(Sn) approximate to 1:4, and x(Co)/x(Sb) approximate to 1:5. Additionally, binary alloys of the constituent systems Co-Sb and Co-Sn were investigated at the same temperature. All the binary data were evaluated by means of a standard Redlich-Kister polynomial fit whereas ternary data were fitted on the basis of an extended Redlich-Kister-Muggianu model for substitutional solutions. An iso-enthalpy plot of the ternary system was constructed. In addition, the extrapolation Model of Toop was applied and compared to our data.