Article ID: ISIJINT-2020-177
Deoxidation equilibria of Fe–Mn–Al melt with Al2O3 or MnAl2O4 were measured at 1773 K. Composition of melts doubly-saturated with Al2O3 and MnAl2O4 were also measured using a crucible comprising these two phases at 1873 or 1773 K. Equilibria with each solid oxide were analyzed using Wagner's Interaction Parameter Formalism (WIPF). In the case of Al2O3 saturation, Al deoxidation curve at 1773 K was similar in shape to that at 1873 K, and the equilibrium oxygen content was approximately 1/3 of that at 1873 K. The deoxidation equilibria were reproduced using WIPF at the composition range above 0.1 mass%Al by using -0.32 as and 10-13.4 as the equilibrium constant of Al2O3 dissolution reaction, both of which were determined through analysis of measured results for Fe–(20 to 30) mass% Mn melt. In the case of MnAl2O4 saturation, accurate values of equilibrium constant were not obtained because of the relatively significant influence of oxygen analysis error. On the contrary, using compositions doubly-saturated with Al2O3 and MnAl2O4, valid values of the equilibrium constant of MnAl2O4 dissolution reaction, 10-15.4 and 10-17.7 at 1873 and 1773 K, respectively, could be determined.