THERMODYNAMIC ASSESSMENT OF THE CA-CU-O SYSTEM

The experimental data on the Ca-Cu-O system at 1 bar total pressure ha ve been reviewed and an optimized thermodynamic description based on p revious assessments of the binary systems is presented. Three ternary oxides are found which do not show significant solid solution and have been treated as stoichiometric compounds, The liquid exhibits a misci bility gap as in the Cu-O binary, Only the copper oxide liquid extends into the ternary field and has been modeled with ternary parameters, A continuous thermodynamic description of the liquid phase from the me tal to the oxide part has been obtained using the two-sublattice ionic liquid model, The set of optimized parameters leads to a consistent a nd accurate thermodynamic description of the Ca-Cu-O system at 1 bar t otal pressure, Calculated CaO-CuOx phase diagrams in air and 1.01 bar of O-2, an oxygen potential diagram, an isothermal section at 1573 K, and various thermodynamic properties are shown and compared with exper imental data. In particular the relative amounts of Cu+ and Cu2+ in th e oxide liquid have been calculated in air and 1.01 bar of O-2.