INVESTIGATIONS OF THE THERMODYNAMIC PROPERTIES OF TE-SATURATED ZNSE-ZNTE SOLID-SOLUTIONS

The activity of ZnTe in Te-saturated ZnSe-ZnTe solid solutions was measured in the temperature range 710-845 K by an electrochemical technique using LiCl-KCl + 5 wt.% ZnCl2 as the molten salt electrolyte. The activity of ZnSe has been calculated by Gibbs-Duhem integration using the alpha function. From the e.m.f. values of the cell measured at different temperatures, the partial, integral and excess molar thermodynamic quantities have been calculated. All the excess partial molar thermodynamic quantities at infinite dilution have been accurately estimated by Chiotti's method. The composition dependence of the alpha function confirms that the system does not follow a regular solution model. The results have been analysed in terms of Darken's stability and excess stability parameters. Detailed analyses of the results confirm that the system is completely miscible in the solid state and consists of a single-phase field throughout the entire range of composition.