Bulk and surface properties of liquid Ga–Tl and Zn–Cd alloys

A simple thermodynamic model, based on the formation of self-associates, has been used to correlate the bulk and surface properties of mixing of liquid Ga–Tl and Zn–Cd alloys at temperatures of 973K and 900K, respectively. The model enables us to explain the positive deviation of the properties of mixing of the two liquid alloys from the ideal solution behavior. Our calculations indicate that the degree of phase separation in Zn–Cd, as measured using the Warren–Cowley short-range order parameter, is less than that in Ga–Tl. With regards to the surface, we show that the surface decomposition in Zn–Cd liquid alloys is greater than in Ga–Tl. We explain the contrast in the bulk and surface properties in terms of the possible roles of the entropic and enthalpic effects on the properties of mixing.