The enthalpy of mixing in the quaternary (Al, Ga, Sn, Zn) system: Calorimetry measurements and Redlich-Kister modelling

The enthalpy of mixing of the (Ga, Sn, Zn) liquid phase has been explored a t 715 K by Calvet drop calorimetry. Following the three isopletic cuts x(i) = x(j) we have determined the ternary term of a fifth order Redlich-Kister model. An exploration of the quaternary (Al, Ga, Sn, Zn) system along the two isoplethic cuts x(Ga) = x(Sn) = x(Zn) and x(Al) = x(Ga) = x(Zn) has bee n realized too. A Redlich-Kister polynom established for this quaternary sy stem was extrapolated up to the ternary (Al, Sn, Zn) border system which re mains inaccessible to calorimetry with an open crucible. A Darken quadratic model based on a statistical Bragg-Williams description of the (Al, Sn, Zn ) liquid phase is compared to this calorimetry extrapolation.