Thermodynamic modeling of liquidus surface of the phase diagram of Cu 2O-Al 2O 3-ZrO 2 system

Calculations of the liquidus lines for the phase diagrams of the Cu 2O-Al 2O 3, Cu 2O-ZrO 2 and Al 2O 3-ZrO 2 binary systems were made as well as the calculations of liquidus surface for the phase diagram of the Cu 2O-Al 2O 3-ZrO 2 ternary system. The theory of subregular ionic solutions was used in thermodynamic modeling. The values of the theory parameters Q, thermodynamic characteristics (melting temperature, heat of fusion, and entropy of fusion) for CuAlO 2 compound were determined. The values of the equilibrium constants of the transition from solid to liquid for Cu 2O, Al 2O 3, ZrO 2 and CuAlO 2 were defined. Calculations of activity of Cu 2O, Al 2O 3, and ZrO 2 in the oxide melt for Cu 2O-Al 2O 3 and Cu 2O-ZrO 2 diagrams show that a (Cu 2O), a (Al 2O 3) and have negative deviation from Raoult’s law. The calculated activity of the aluminium oxide has good agreement with the literature. Construction of the liquidus surface for the Cu 2O-Al 2O 3-ZrO 2 ternary system allows to define the points of the nonvariant transformation. Results of the thermodynamic modeling of the Cu 2O-Al 2O 3-ZrO 2 ternary system show that equilibrium “oxide melt-pure solid copper oxide-pure solid aluminium oxide” is realized in this system. This equilibrium is not characteristic for Cu 2O-Al 2O 3 binary system. Results of this work can be used for the analysis of the bronze production and for the analysis of slag behavior for the copper and copper-based alloys industries.