Thermodynamic investigation of Pt-Pb binary alloys

The enthalpy of formation of PtPb compound was determined by reaction calorimetry at room temperature. The heat content of the same compound was measured by drop calorimetry in the solid the liquid and the two-phase states, and its heat capacity was derived. The enthalpy of formation of the Pt3Pb compound has been deduced. In order to apply the regular associated solution model we calculated the free enthalpy of formation of the liquid from the phase diagram and the thermodynamic functions of the solid intermediate compound and the liquid. The application of the model allowed us to explain the behaviour of the Pt-Pb melt by the existence of two kinds of associates, i.e. Pt2Pb and PtPb. (C) 2000 Elsevier Science S.A. All rights reserved.