Calorimetric study and thermodynamic description of liquid In-Li alloys

This paper presents the results of the integral molar mixing enthalpy of liquid In-Li alloys, measured calorimetrically at three temperatures: at 653 K for the concentration range of In lower than 0.12 at.%, at 940 K for the concentration range of In lower than 0.27 at.%, and at 994 K in the entire concentration range. The obtained experimental values in these ranges of temperatures indicate that the integral molar enthalpy of liquid alloys from this binary system is independent of temperature. The available experimental data of partial or molar Gibbs free energies, together with the enthalpy of mixing, were used for the elaboration of the equation in the form proposed by Redlich and Kister, which describes the dependence of the excess Gibbs energy on the concentration and temperature. The experimental thermodynamic values of the excess free energy, mixing enthalpy change and activity were compared with those calculated with the use of the elaborated Redlich-Kister equation. Moreover, the partial structure factors and short-range order parameter were calculated and discussed in relation to the thermodynamic properties and the phase diagram of the In-Li system.