Evaluation of corrosion behaviour on Mn-Cr austenitic steels using 0.1 M HCl solution

One of the attractive low activation steels is the austenitic Mn-Cr steel from the view point of waste disposal because of few long-lived nuclides. In this paper, three types of Mn-Cr austenitic steels were fabricated by vacuum induction furnace. Then plates with 10 mm thickness were fabricated by hot-rolling. The physical metallurgy of these steels was studied by the corrected Schaeffler diagram, X-ray and electron diffraction patterns. The corrected Schaeffler diagram and X-ray diffraction (XRD) results have shown that the matrix of these steels is a single γ-phase structure. Also, the corrosion behaviour in 0.1M HCl solution was evaluated by open-circuit potential, Tafel polarization, and electrochemical impedance spectroscopy (EIS). The results of Tafel polarization experiments show corrosion current density of all three Cr-Mn steels is in the range of 10-4 A cm-2 which indicates their appropriate resistance in this acidic environment. The Nyquist plots showed that polarization resistance from the first to third Cr-Mn steels decreases. This trend is due to increase in corrosion current density which corresponds to Tafel polarization curves.