Surface tension of liquid Ag-Sn alloys: Experiment versus modeling

The maximum bubble pressure method has been used to measure the surface tension of pure tin and seven binary alloys with concentrations of 15, 30, 40, 60, 75, 87.8, and 96.2 at.% Sn, Measurements were performed at the temperature range from 500 to about 1400 K depending on the composition of the investigated alloy. Densities of the Ag-Sn alloys were measured dilatometrically. The linear dependencies of densities and surface tensions on temperature were observed, and they are described by a straight-line equation. Experimental data of the surface tensions were compared with calculations using Butler's model, which assumes an equilibrium between the bulk phase and the monolayer surface phase. Excess Gibbs energies of silver and tin necessary in calculations were taken from the optimized thermodynamic parameters reported recently from Tohoku University. It is shown that the calculated surface tension data from the optimized thermodynamic parameters of the liquid phase of the Ag-Sn are in good agreement with the experimental results.