In situ study of selective manganese oxidation on low-alloyed steel using high-temperature cyclic voltammetry

Abstract

High-temperature cyclic voltammetry was applied to study the early stage oxide formation on low-alloyed steels with different manganese contents. Experiments were carried out at 560 °C using yttria stabilized zirconia (YSZ) as solid eletrolyte and reduced oxygen partial pressure. The acquired voltammograms show the oxidation and reduction sequence from pure iron to hematite. Redox transitions of Mn oxides appear at more positive potentials compared to their standard electrode potentials as a result of incorporation of Mn ions into the Fe₂O₃ lattice. According to Raman analysis, Fe₂O₃ peaks are shifted to lower wavenumbers with increasing Mn content. EDX analysis was performed as supporting analytical technique to verify the Raman results. The manganese oxidation behaviour on low alloyed steels as well as the benefits of HT-CV in the field of high-temperature corrosion were successfully demonstrated.