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

The maximum bubble pressure method has been used to measure the surface ten sion 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 tempera ture range from 500 to about 1400 K depending on the composition of the inv estigated alloy. Densities of the Ag-Sn alloys were measured dilatometrical ly. The linear dependencies of densities and surface tensions on temperatur e were observed, and they are described by a straight-line equation. Experimental data of the surface tensions were compared with calculations u sing Butler's model, which assumes an equilibrium between the bulk phase an d the monolayer surface phase. Excess Gibbs energies of silver and tin nece ssary in calculations were taken from the optimized thermodynamic parameter s reported recently from Tohoku University. It is shown that the calculated surface tension data from the optimized thermodynamic parameters of the li quid phase of the Ag-Sn are in good agreement with the experimental results .