The excess enthalpies of liquid Ag-Sb-Te and Ag-Bi-Te alloys

The excess enthalpies of liquid alloys in the ternary systems Ag-Sb-Te and Ag-Bi-Te were determined in a heat flow calorimeter for five sections AgyBi 1-yTe with y = 0.2, 0.4, 0.5, 0.6, and 0.8 at 1173 K, for the section Ag0.5 Bi0.5-Te at 1073 K, and to complete recent measurements at 1073 and 1173 K for the section Ag0.5Sb0.5-Te. The thermodynamic functions of the systems A g-Sb, Ag-Bi and Ag-Te were reoptimized with the Lukas programs using the as sociation model. Ternary interactions were taken into account for the analy tical description of the excess enthalpies of the liquid Ag-Sb-Te and Ag-Bi -Te alloys. The enthalpy surfaces of the systems are determined by valleys of exothermic minima between the congruently melting compounds in the binar y tellurium systems. The values of exothennic enthalpies decrease with incr easing temperature, due to the dissociation of the telluride associates in the binary systems.