Thermodynamic properties of liquid Au-Cu-Sn alloys determined from electromotive force measurements

► A full thermodynamic description of the liquid ternary Au-Cu-Sn system is reported. ► The electromotive force method with a liquid electrolyte was used to determine the activity of tin in the alloys. ► The partial free energies of tin in this system were calculated from the obtained EMF values. ► The Gibbs-Duhem integration was used to calculate the integral Gibbs free energy and integral enthalpy of the entire system.