The properties of the liquid phase in the Cd–Te system are fit using thermodynamic properties of CdTe(c) recently optimized by the author. These include a high temperature heat capacity significantly lower than commonly used such that the enthalpy of formation of CdTe(c) at its melting point is about 10 kJ/mol less negative than previously thought. An associated solution model with Cd, CdTe, and Te species is used. Seven adjustable parameters are sufficient to quantitatively fit the liquidus and partial pressures of Te2 and Cd. Additional partial pressures for Te rich CdTe(c) near its melting point are extracted from an earlier study and tabulated. The parameters giving good fits to the liquidus and partial pressures give only a fair fit to the enthalpy of mixing of the liquid phase. Moreover, the parameters giving a good fit to the enthalpy give poor fits to the other data. The sensitivity of the different data types to changes in the interaction parameters of the associated solution model is established. A variation of ±160 J/g atom in the enthalpy parameter determining the CdTe–Te interaction is sufficient to double the fractional standard deviation between experimental and calculated partial pressures of Te2 over Te rich CdTe(c) from 0.034 to 0.07. Because the degree of association is near its maximum, the measures of fit to the data are insensitive to changes in the parameters determining the Cd–Te interaction.
Brebrick, Robert F., "The Cd-Te Phase Diagram" (2010). Mechanical Engineering Faculty Research and Publications. 261.
ADA Accessible Version
Accepted version. CALPHAD, Vol. 34, No. 4 (December 2010): 434-440. DOI. © 2010 Elsevier. Used with permission.