Thermodynamic description of the systems Cd-Te, Hg-Te and Cd-Hg-Te using the model of associated liquid solution

Abstract

This study is devoted in the search of a model describing the best possible liquid and solid phases of the systems Cd-Te, Hg-Te and Cd-Hg-Te. For the liquid phases, we used the model of Sub-regular Associated Solution (SAS) in which we suppose the existence of associated species CdTe and HgTe with the simple species Cd, Hg and Te. The excess free enthalpy of mixture ΔexGL is then expressed as a polynomial of Redlich-Kistler. In the ternary diagram, the excess free enthalpy ΔexGS is expressed in the model of Pseudo-Regular Associated Solution (PRAS). The value of parameters, the thermodynamic quantities of dissociation, for the associated species is calculated by the numerical resolution of the phase equilibrium equations. The results of this calculation indicate a more marked associated character in Cd-Te than in Hg-Te with a pseudo-regular behaviour of the binary liquid Cd-Te. In the ternary, we note a prevalence of the interactions Cd-CdTe and Hg-HgTe compared to the interactions Cd-HgTe, Hg-CdTe, CdTe-HgTe and Cd-Hg-Te.