Phase equilibria of the Al2O3-SiO2-CrOx system at 1600 °C and pO2 of 10-10-10-11 atm

Abstract

The equilibrium phase relations of the Al2O3-SiO2-CrOx system were experimentally studied at 1600 °C and pO2 of 10-10-10-11 atm. The high-temperature isothermal equilibration experiments were conducted in a vertical tube furnace, followed by drop quenching and direct phase composition analysis using an Electron Probe X-ray Microanalyzer. The single liquid equilibria, liquid-solid phase equilibria including liquid-corundum, liquid-mullite, and liquid-cristobalite, as well as the three-phase equilibria of liquid-cristobalite-corundum and liquid-corundum-mullite, were observed. The 1600 °C isothermal sections of the quasi-ternary Al2O3-SiO2-CrOx phase diagram at pO2 of 10-10 and 10-11 atm were constructed. The present experimental results display significant discrepancies with the simulations by MTDATA, FactSage, and Thermo-Calc.