Calorimetric measurements of the ternary Ag-Au-Sn system

Using a Calvet type calorimeter, the enthalpy of mixing in the ternary system Ag-Au-Sn was determined at 873 and at 1023 K. The investigations were carried out at three cross-sections with constant molar ratios of Ag:Sn = 1:1, 1:2, and 1:9 at 873 K, and at four cross-sections with constant molar ratios of Ag:Sn = 2:1, 1:1, 1:2, and 1:9 with Au added in the concentration range between 0 and 55 at.%. The substitutional solution model of Redlich-Kister-Muggianu was used for a least square fit of the experimental data in order to get an analytical expression for the integral enthalpy of mixing. The ternary extrapolation models of Kohler, Muggianu and Toop were used to calculate the integral enthalpy of mixing and to compare measured and extrapolated values.