Theoretical calculations of the surface tension of Ag(1−x)-Cu(x) liquid alloys

► A thermodynamic model for calculating the surface tension, and its temperature and composition dependences, of liquid binary alloys is described. ► The model does not require the prior knowledge of the surface concentration and Gibbs energy. ► The surface tension of the liquid Ag-Cu binary alloys has been calculated as a function of temperature and concentration. ► The calculated values agree well with existing experimental data.