Thermodynamic Descriptions for the Cd-Te, Pb-Te, Cd-Pb and Cd-Pb-Te Systems

Abstract

The thermodynamic behaviors of the Cd-Te, Pb-Te, Cd-Pb and Cd-Pb-Te systems are critically analyzed in this work by means of the calculation of phase diagrams (CALPHAD) method. The liquid phases containing Te are described by the associated solution model, which is capable of dealing with V-shaped curves of mixing enthalpies in solution phases, sharp maxima of liquidus curves in phase diagrams, and abrupt changes in activity plots. The binary compounds, CdTe and PbTe, are considered to be stoichiometric in the two binary systems, but they form a line compound described by (Cd,Pb) 1 (Te) 1 in the ternary system. The fcc phase, in which only Cd and Pb elements are present, is treated with the substitutional solution model. The experimental data available in the literature are extensively assessed, from which the thermodynamic parameters necessary for each phase are obtained. Various calculated phase equilibria and thermodynamic properties are compared with the experimental data. The excellent agreement indicates that this work contributes to the study of phase stabilities in the Cd-Pb-Te system.