EXPERIMENTAL MIXING ENTHALPY OF THE LIQUID (AL, GA, SN) SOLUTION - DARKEN AND REDLICH-KISTER MODELING

The mixing enthalpy of the liquid (Al, Ga, Sn) phase is described by t hree Darken quadratic formalisms, each one relative to one solvent and two solutes (obtained by circular permutation), or by a sole fifth-or der Redlich-Kister polynomial. The experimental binary and ternary mea surements were carried out in a Calvet type calorimeter at 950 K. Only three isopleths (x(i) = x(j)) were explored in the triangle of ternar y compositions, giving the numerical proof that the Darken approach is sufficiently accurate to take into acount all the possible experiment al data. The final Redlich-Kister modelling fits the retained sets of data, in the whole ternary composition range, with an accuracy of +/-1 00 J/mol whereas the experimental uncertainty can be estimated at +/-1 50 J/mol.