Thermodynamic and Structural Study of the Copper-Aluminum System by the Electrochemical Method Using a Copper-Selective Beta″ Alumina Membrane

The liquid phase thermodynamics of mixing of the copper-aluminum binary system are investigated as a function of temperature and composition using the electrochemical potential difference method. A copper-selective beta″ alumina is used as a solid electrolyte, synthesized through ion exchange, sintering from base oxide powders, and the floating zone method of crystal growth. Measured thermodynamics of mixing data were used to inform short-range ordering in copper-aluminum melts through Darken’s factor for excess stability and Bhatia–Thornton structure factors, revealing a strong departure from ideality and pronounced ordering. Mixing properties were used to predict viscosity and self-diffusion coefficients. Features observed in calculated electronic entropy of mixing for copper-aluminum were compared with trends in viscosity, demonstrating the utility of electronic properties of mixing in the description of structure–properties in this liquid binary system.