Thermodynamics and surface properties of liquid Ga-X (X = Sn, Zn) alloys

The mixing behaviour of Ga-Sn and Ga-Zn segregating alloy systems has been investigated by the Quasi-Chemical Approximation (QCA) in the frame of the Quasi-Lattice Theory (QLT) combined with a statistical mechanical theory. Assuming the order energy parameters as temperature dependent, various thermodynamic quantities are calculated at different temperatures. Thermodynamic properties of both systems deviate positively from the Raoult's law. The energetics of mixing in liquid alloys has been analysed through the study of surface properties (surface tension and surface composition) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter). Theoretical results are in a good agreement with the corresponding literature data and support a weak demixing tendency in Ga-Sn and Ga-Zn liquid alloys.