Inside a silica tube, a piece of Al was brought in contact for a very short time (1–60 s) with liquid Fe containing different dissolved oxygen (O) levels (170–1800 ppm) at 1600°C. The purpose was to investigate the inclusion formation during the initial deoxidation period. Intermetallic compounds of the Fe–Al system appeared due to the interdiffusion of Fe and Al, and the reaction between AL and O at the interface gave rise to the formation of Al2O3 inclusions. These inclusions showed different characteristics according to the initial O level in liquid Fe and the interaction time. With lower O content, the amount of inclusions decreased and faceted particles were dominant among the morphologies. While increasing the O content to 780 and 1800 ppm, the inclusion number increased drastically and numerous small spherical inclusions were observed. Further away from the reaction front, clusters of fine particles were formed through a collision–coagulation mechanism. The change in Al2O3 morphology with the initial O content was interpreted as a consequence of different supersaturation degrees with respect to AL and O.
