Experimental phase equilibria study and thermodynamic modelling of the “CuO0.5”-AlO1.5-SiO2 ternary system in equilibrium with metallic copper

Abstract

Phase equilibria studies were undertaken on the “CuO0.5”-AlO1.5-SiO2 system in equilibrium with metallic copper using equilibration and quenching technique followed by the electron probe X-ray microanalysis (EPMA). The liquidus of the “CuO0.5”-AlO1.5-SiO2 system, including the two 2-liquid miscibility gaps in the system as well as the cuprite (Cu2O), corundum (Al2O3), delafossite (CuAlO2), tridymite and cristobalite (Si1-x(CuAl)xO2), and mullite (Al6+2xSi2-2xO13-x) primary phase fields has been characterized. New experimental results together with phase equilibria and thermodynamic literature data were used to obtain a self-consistent set of parameters of the thermodynamic model for all phases. The liquidus projection of the “CuO0.5”-AlO1.5-SiO2 system was presented for the first time in the full range of temperatures and compositions. It was found that the simultaneous dissolution of a small amount of alumina and copper oxide (CuAlO2) in SiO2 phases stabilize cristobalite over tridymite at low temperatures.