Thermodynamic investigations in the system Bi-Sn-Te

The excess enthalpies of liquid Bi-Te alloys and liquid Bi-Sn-Te alloys wer e determined in a heat-flow calorimeter. The measurements in the-binary sys tem were carried out at 1173 K over the whole range of compositions and for the ternary system along the sections BiySnl-y_-Te with y=0.2, 0.5 and 0.8 at 1173K and with y=0.5 at 1073 K. The maxima of the exothermic enthalpies in the ternary system are found on a line stretching from Bi2Tes to SnTe. The association model with additional ternary interaction parameters was ap plied for the analytical description of the thermodynamic data of the terna ry melt. The results of the section Bio.5Sno.5-Te were compared with those of the Redlich-Kister formalism applied in the systems Bi-Ge-Te and Bi-Pb-T e. In addition, the phase equilibria of the quasibinary section SnTe-Bi wer e investigated by DTA and X-ray diffraction measurements. The thermodynamic functions were optimized and the phase diagram of this system was calculat ed using the experimental data.