Phase equilibria in the Ga–P system. Calculation of activities and vapour pressures using a simple asymmetrical solution model

Abstract

AbstractKRUPKOWSKI'S expression of activity coefficients has been applied to the liquid binary mixed phase of Ga–P. An interaction parameter of α = 1909 – 4.107 T and an asymmetry coefficient of m = 1.448 were determined from liquidus data and an entropy of fusion of GaP of 16.8 e.u. per mole at 1743 K. The activity coefficient of phosphorus along the liquidus curve shows a minimum at xP = 0.032. There is an excellent agreement between calculated and experimental activities and vapour pressures over the whole controllable range of concentrations of the liquid phase. A total phosphorus pressure of 30.8 atms was calculated for the melting point of GaP.