Interfacial reaction of nitrogen with molten iron: a theoretical study

The effect of oxygen on the interfacial reaction rates of nitrogen dissolution into molten iron has been studied using a new theoretical model and the measurements by an isotope-exchange technique in our previous studies. In our model, surface activities of the vacant sites and the sites occupied by oxygen have been proposed to predict the interfacial reaction rates and to clarify the rate-determining step of nitrogen dissolution into molten iron using the oxygen adsorption that had been obtained based on Butler's equations. It was found that the experimental results were in good accordance with the predicted values for adsorbed N-2 dissociation control rather than those for N-2 adsorption control in the low oxygen and sulphur activity region, yielding that the dissociation of nitrogen molecule into atoms at the surface is the rate-determining step of the interfacial reaction of nitrogen dissolution into molten iron.