Mechanism Of Aluminum Deoxidization In Fe-O-Al Melt Based On Two-step Nucleation Theory

Aluminum and aluminum alloy were widely used in the deoxygenation of liquid steel and the refining process. It’s plays an important role that researching the reaction mechanism of aluminum deoxidation to improve the cleanness of Al-killed steel and optimize and control the content, size, size distribution and morphology of inclusionsFirstly, the paper introduce and analyze the situation of equilibrium experiment research of the Al-killed steel which have been studied by the domestic and foreign scholars since 1950.We have fond that the content of dissolved oxygen at the reaction balance have great differences when aluminum were on the same content by various researchers measured. The scholars also want to explain the reason by thermodynamics and propose a variety of models, but many of them can not explain the equilibrium experiment of al-killed. This the article is based on the two step-nucleation theory to analyze and consider the aluminum deoxidation in the steel not only all generate α-Al2O3, but also exist many products of equilibrium reaction are metastable phases(Al2O3 cluster).Aluminum deoxidizing experiment have been carried out. The deoxidation reaction of the first three samples are generate composite inclusions of Fe2O3 and Al2O3 for the short of aluminum. In this paper, the researcher also analyzed the inclusions and the interface between inclusion and ferro matrix. Samples 5 generated a compound for Fe and Al. Finding that there are still many Al and O elements in the samples surrounding when scanning, where it was initially thought to be solid solution of Al and O, and alumina clusters or newly formed alumina crystal nucleus.In the paper, the DSC analysis was carried out on the aluminum deoxidation and found that there is the larger endothermic peaks in it. The article also analyze all kinds of peaks in the process of arising and cooling temperature.There are various metastable phases existed when the aluminum deoxidation reaction attend to balance, but how are these metastable phases formed? This article have studied on the mechanism of aluminum deoxidation reaction. Considering that in the aluminum deoxidation process, the aluminum not only react with the atomic state but also with the form of clusters, generating all kinds of aluminum-oxygen clusters.The process of forming(Al2O3)1 and(Al2O3)2 have also be studied.How these alumina metastable phases aggregate and grow, and how alumina crystal nucleus grow?We fond that these clusters will aggregate after collided with each other, the total energy of reaction process is reduced and meet the requirements of thermodynamics, especially which is better to aggregation reaction in the process of solidification and cooling. After alumina nucleation, the crystal nucleus will absorb the atomic oxygen around or the alumina clusters to grow up.