ACTIVITY OF OXYGEN IN LIQUID GA-IN-SB ALLOYS .2. TERNARY ALLOYS

These data are compared with a comprehensive thermodynamic model which describes/predicts the temperature and composition dependence of gamma-0-degrees in the entire range of liquid alloys. Various extensions of Wagner's solvation shell model have been investigated. A rather simple version with one temperature dependent energy parameter per binary edge system was found to be sufficient for a quantitative description of all ternary, binary and unary In gamma-0-degree data with an error of less than +/- 0.5 in most cases and less than +/- 1.0 in the worst cases of low temperature and very low oxygen potentials. The calculated ternary data are predictions and not optimized with ternary parameters. Various experimental conditions have also been investigated. It is demonstrated that a high effort is necessary for the measurement of reproducible and reliable gamma-0-degrees data in the Ga-In-Sb system. This challenging system may serve as an example for the necessary modifications and improvements of the coulometric titration method when working in the limiting region of low oxygen potential and solubility.