Equilibrium Relationships between Oxide Compounds in MgO–Ti₂O₃–Al₂O₃ with Iron at 1873 K and Variations in Stable Oxides with Temperature

Abstract

It is important to determine the equilibrium relationships between the oxide compounds in MgO–Ti₂O₃–Al₂O₃ and iron to avoid Al₂O₃ or MgO·Al₂O₃ formation and for inclusion control. In this study, the equilibrium relationships between the oxide compounds in MgO–Ti₂O₃–Al₂O₃ and molten iron are investigated at 1873 K. The phase-stability diagrams, which show the equilibrium relationships between the oxide compounds in MgO–Ti₂O₃–Al₂O₃ and molten iron, are described. It is also important to know the oxides that newly form after solidification. Accordingly, the temperature-dependences of the stable compounds that newly form after solidification were investigated using the thermodynamic calculation software FactSage 6.1. Although the compounds formed after solidification are not necessarily the same as the equilibrium oxide compounds at 1873 K, the correlation between them can be confirmed. In particular, under the unstable condition of MgAl₂O₄ at 1873 K, it is found that the formation of MgAl₂O₄ could also be suppressed after solidification.