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Free keywords:
Grain boundaries; High temperature corrosion; Hot rolling; Internal oxidation; Iron alloys; Iron oxides; Manganese alloys; Manganese oxide; Oxygen; Scale (deposits); Surface chemistry, A alloy; B TEM; B XPS; C high temperature corrosion; C kinetic parameter; C selective oxidation; Hot-rolled; Oxygen partial pressure; Selective oxidation; Silicon contents, Silicon alloys
Abstract:
The kinetics of selective oxidation in iron-manganese-silicon alloys of varying silicon contents was examined at 700°C and oxygen partial pressure of 2.9×10−22 bar for up to 2 h. The investigation revealed a linear mass gain over time, suggesting oxygen uptake as the rate-controlling step of reaction. Internal oxidation depth particularly along grain boundaries increased considerably with increasing silicon content. Differences in microstructure and near-surface chemistry of the alloys as a function of the silicon content are discoursed on. The results point to the crucial role of a thin oxide layer, a solid solution between FeO and MnO, in the oxidation process. © 2021 The Authors
