The excess enthalpies of liquid Ag-Ga-Te and Ag-In-Te alloys

Abstract

The excess enthalpies of liquid alloys in the ternary systems Ag-Ga-Te and Ag-In-Te were determined in a heat flow calorimeter for four sections AgyGayTe with y = 0.2, 0.4, 0.5. and 0.6 at 1173 K, for the section Ag0.5Ga0.5-Te at 1073 K, for five sections AgyIn1-y-Te with y = 0.2, 0.4, 0.5, 0.6, and 0.8 at 1173 K, and fur the section Ag0.5In0.5-Te at 973 and 1073 K. The thermodynamic functions of the system Ag-Ga and Ag-In were optimized, using the association model and the Lukas program to get a reliable data base for the calculation of tel nary thermodynamic data. However, ternary interactions had to be considered for the analytical description of the excess enthalpies of the liquid Ag-Ga-Te and Ag-In-Te alloys. The enthalpy surface of both systems is characterized by a valley of exothermic minima from the congruently melting compound Ag2Te to Ga2Te3 or In2Te3. The numerical values of the enthalpies decrease with increasing temperature by dissociation of binary telluride associates. (C) 2001 Elsevier Science B.V. All rights reserved.