Thermodynamic, Surface and Viscous Properties of Molten Ga-Zn Alloys

We have theoretically investigated the concentration-dependence of the thermodynamic properties, surface tension and viscosity of molten Ga-Zn alloys at 750 K. We have computed thermodynamic functions using statistical theory in the framework of quasi-chemical approximation for regular alloys; and surface composition and surface tension of the alloys using the energy parameter of quasi-chemical calculations in Prasad's model. For comparison, we have also computed the surface properties from Butler's model. For the computation of viscosity, different equations have been employed that contain thermodynamic functions such as heat of mixing etc. Theoretically computed thermodynamic functions are in good agreement with the experimental results. The surface tension and viscosity computed from different approaches show similar variations with a relatively good harmony in themselves. The surface tension and viscosities of the Ga-Zn system at 750 K decrease with the addition of Ga atoms showing a small negative deviation from the additive rule of mixing. All theoretical approaches predict deviations from ideality both in the surface tension and viscosities, relatively larger deviations in the intermediate region of bulk concentrations. The analysis reveals that the Ga-Zn system at 750 K has weak demixing tendency and Ga-component with smaller surface tension is surface active component.