Analysis of the mercury-cadmium-zinc-tellurium phase diagram with an associated solution model
Abstract
All of the published information on the phase diagrams and thermodynamic data for the crystalline compounds HgTe, CdTe, and ZnTe and their elements along with the ternaries HgCdTe, HgZnTe, and CdZnTe are critically collected and assessed. In particular the Gibbs energy of formation for each binary compound is subjected to a third law analysis to obtain self-consistent thermodynamic data bases. The liquid phase is modeled as an associated solution in which the interactions of the species are given by quadratic and cubic terms in the species mole fractions with linearly temperature dependent coefficients. The associated species being considered in the system are HgTe, CdTe, and ZnTe. The solid solution of Hg$\sb{1-u-v}$Cd$\sb{u}$Zn$\sb{v}$Te is characterized by assuming that its thermodynamic components, HgTe(s), CdTe(s), and ZnTe(s) mix like a quasiregular solution. Quantitatively satisfactory fits are obtained for each subsystem by fitting the phase diagram to the diverse available experimental data. The model parameters obtained provide the reliable means of extrapolating and interpolating some useful thermodynamic properties. Once all of the liquid and solid solution model parameters are fixed by these fits, certain aspects of the Hg-Cd-Zn-Te phase diagram are calculated. These include Te-rich liquidus and tie-lines giving liquid composition and temperature required to give a solid solution of specified composition.
This paper has been withdrawn.