CALORIMETRIC INVESTIGATIONS OF LIQUID GE-TE AND SI-TE ALLOYS

The heats of solution of Ge and Te in liquid Ge-Te alloys and of Si in liquid Si-Te alloys were determined in a heat flow calorimeter at dif ferent temperatures. The excess enthalpies were calculated from the me asured heat effects. In addition the heats of formation of liquid Ge-T e alloys were measured at 1203 K. The associate model was used to desc ribe the thermodynamic functions. Minima of the enthalpy curves in the Ge-Te and Si-Te systems at 1213 K were found at 57 mol.% Te and -11.2 kJ mol(-1) and at 62 mol.% Te and -22.3 kJ mol(-1) respectively. A te mperature dependence of the excess enthalpies was only observed in the Ge-Te system below about 1093 K. The enthalpies of the Si-Te system e xhibited an almost linear temperature dependence.