EXPERIMENTAL INVESTIGATION AND THERMODYNAMIC CALCULATION OF EXCESS-ENTHALPIES IN THE AG-PB-TE SYSTEM

The excess enthalpies of liquid alloys in the ternary system Ag-Pb-Te were experimentally determined at 973, 1073 and 1173 K in a heat flow calorimeter. Five sections AgyPb1-y-Te with constant concentration rat ios x(Ag)/x(Pb) were measured. The enthalpy surface in the ternary sys tem is characterized by a valley stretching from the exothermic minimu m in the system Pb-Te (-26.9 kJ mol(-1) at x(Te) =0.337) to the exothe rmic minimum in the system Ag-Te (-21.0 kJ mol(-1) at x(Te)=0.520) at 1173 K. The association model was applied for the analytical descripti on of the ternary liquid. Additional ternary interaction parameters ha d to be used for the calculation of the excess enthalpies which were o btained by adjusting the curves to the experimental data using the lea st squares method. (C) 1998 Elsevier Science S.A. All rights reserved.