Influence of FeO and sulfur on solid state reaction between MnO−SiO₂−FeO oxides and an Fe−Mn−Si solid alloy during heat treatment at 1473 K

To clarify the influence of FeO and sulfur on solid state reaction between an Fe−Mn−Si alloy and MnO−SiO₂−FeO oxides under the restricted oxygen diffusion flux, two diffusion couples with different sulfur contents in the oxides were produced and investigated after heat treatment at 1473 K. The experimental results were also compared with previous work in which the oxides contained higher FeO. It was found that although the FeO content in the oxides decreased from 3wt% to 1wt% which was lower than the content corresponding to the equilibrium with molten steel at 1873 K, excess oxygen still diffused from the oxides to solid steel during heat treatment at 1473 K and formed oxide particles. In addition, increasing the sulfur content in the oxides was observed to suppress the diffusion of oxygen between the alloy and the oxides.