Thermodynamic and kinetic studies of some Group III and Group V elements and alloys by solid state electrochemical techniques

The Gibbs free energy of forming gallium sesquioxide and indium sesquioxide are measured using a CO2--CO--O2 gas reference electrode and calcia stabilized zirconia as the solid electrolyte. The free energies are: ΔG0/sub f/(β-Ga2O3(c)) equals -(265,309 +- 152) + (82.47 +- 0.16) (T/K) cal mol-1 and ΔG0/sub f/(In2O3 (c)) equals -(223,160 +- 137) + (79.47 +- 0.12) (T/K) cal mol-.1 A solid state galvanic cell is employed to measure gallium activities in Ga--Sb liquid alloys. Results show moderate negative deviations from ideality in the composition range 0.039 less than x/sub Ga/ less than 0.833. Partial molar enthalpies and entropies are calculated, and agree wih calorimetric data. Results are combined with calorimetric data to calculate the liquidus temperatures of the Ga--Sb system, which are in excellent agreement with measurements. Effect of short-range ordering is also investigated. Coulometric titration techniques are used to investigate the solubility and diffusivity of oxygen in liquid indium. Dissolved atomic oxygen is found to follow Henry's law and a saturation solubility of x0/sup sat/ equals 3.3 x 10-3 is determined at 9080K. From a galvanostatic response of an indium electrode, an oxygen diffusivity of 2.2 x 10-6 cm2 s-1 is found, in good agreement with other available data