Abstract
Aluminium-oxygen equilibria between CaO-Al2O3 melts and liquid iron were studied in the temperature range of 1823 to 1923 K, using alumina and lime crucibles. The equilibrium constant K for the reaction: 2Al+3O=Al2O3 was discussed with reference to the supersaturation for nucleation of alumina, and compared with the previous experimental and thermodynamic data. The supersaturation was observed in the experiments in which an Fe-Al alloy with low concentrations of initial oxygen was used under the condition of no stirring. Supersaturation increased with a decrease of oxygen content in liquid iron. Two types of alumina inclusions with a size of 25 μm and below 0.1 μm were observed by SEM.
