Thermodynamics of the Cu–Bi system determined by vapour pressure measurements

Abstract

Application of Knudsen method for solid and liquid copper in the temperature range 1300–1725K, liquid bismuth in temperatures 769–1129K, and liquid Cu–Bi alloys in temperatures from 871 to 1469K, provided experimental data which made it possible to characterize thermodynamic properties of liquid and gaseous phase of Cu–Bi system. Standard enthalpies of copper and bismuth monomers sublimation and dissociation of bismuth dimer as well as parameters of Regular Associated Solution model (RAS), describing excess Gibbs energy of liquid phase of the examined system, were determined. The obtained model takes into account also presence of disturbances in vaporization of bismuth dimer from Cu–Bi alloys by introducing into the model a parameter which describes the evaporation coefficient of that particle.