Thermodynamic study of the Ag-Sb-Te system with an advanced EMF method

The phase transition temperature, where Sb2Te3 and Ag2Te form AgSbTe2 at 101.3 kPa pressure, was found to be T = 620.5 K. Standard thermodynamic quantities of SbxTe1−x and AgSbTe2 were calculated from the results obtained as well as Gibbs energies of formation as linear functions of temperature. Each test electrode, containing 3 phases in equilibrium, was synthetized separately inside an evacuated quartz glass ampoule and quenched into ice water. The contents of the test electrodes were confirmed by SEM-EDS analysis. Also, the average solubility of substances in the test electrodes was calculated from the SEM-EDS data obtained. The parasitic thermovoltage involved with the measured EMF was determined by symmetrical cell arrangement and compensated from the experimental values.