Thermodynamic properties and phase equilibria of the lead-tellurium binary system

The liquidus curve of the Pb-Te binary was measured using two different DTA systems, one employing a small sample (0.2 g) and the second a large sample (5 g). An additional liquidus measurement method was employed for the Pb-rich region in which the liquid equilibrated with PbTe was analyzed chemically. The liquidus for the Pb-PbTe subsystem obtained is in agreement with several sets of data reported in the literature. The literature data for the PbTe-Te are in disagreement. Our measured values resolve this discrepancy and yield a eutectic temperature of 410.9±0.8°C at 89.1±0.3 at % Te. The system was thermochemically modelled using an associated solution model for the liquid phase and a defect model for PbTe. This model not only accounts for compositional and temperature dependences of the thermodynamic data but also for electron and hole concentrations within the homogeneous range of PbTe(c).On leave from India Institute of Technology-Kanpur, Kanpur, India.