EXCESS-ENTHALPIES AND PHASE-EQUILIBRIA IN THE PB-SB-TE SYSTEM

The excess enthalpies of liquid binary Sb-Te alloys and of the ternary Pb-Sb-Te system were determined in a heat-flow calorimeter along the sections PbySb1-yTe with y=0.2, 0.5 and 0.8 at 1173 K and with y=0.5 a t 1073 K. The largest values of the exothermic enthalpies are found on a line stretching from PbTe to Sb2Te3. The association model with add itional ternary interaction parameters was applied for the analytical description of the ternary melt. In addition, the phase equilibria wer e determined by DTA and X-ray diffraction measurements. The thermodyna mic functions of the quasi-binary sections PbTe-Sb and PbTe-Sb2Te3 wer e optimized and the phase equilibria calculated. (C) 1998 Elsevier Sci ence B.V.