A CALPHAD Assessment of the Silver Halide–Silver Sulfate Binary Phase Diagrams

The phase diagrams of the AgCl–Ag 2 SO 4 and AgBr–Ag 2 SO 4 binary systems based on phase equilibria and thermochemical data were evaluated and optimized via the CALPHAD method. Gibbs free energy of liquid phases were described using the substitutional solution model. The compound Ag 9 Cl(SO 4 ) 4 was supposed to be stoichiometric, of which the Gibbs free energy comply with the Neumann–Kopp rule. Self-consistent database with all model parameters were established, and thermodynamic properties (activity) of liquid phase were also calculated for the whole range of compositions according to the Redlich–Kister and Kohler–Toop extrapolation technique, respectively. Results indicate that the calculated data are in excellent agreement with the experimental values reported in the present work. The calculated results involving multi-component systems will be applied to design and prepare composite materials with high ionic conductivity.