Electrochemical behaviour investigation of two Cr-Mn austenitic steels in 0.1 M H2SO4 solution by Mott-Schottky analysis and EIS

In this study, two Cr-Mn-(Ni-free) austenitic steels were fabricated by vacuum induction furnace. Then plates with 10 mm thickness were fabricated by hot-rolling. Electrochemical behaviour of two Cr-Mn steels in 0.1 M H2SO4 solution was investigated by open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Mott-Schottky analysis. The results indicated that the open circuit potentials of two Cr-Mn austenitic steels were found to shift towards positive direction. Also, the potentiodynamic polarization curves suggested that two Cr-Mn austenitic steels showed comparable passive behaviour. Mott–Schottky analysis revealed that the passive films formed on two Cr-Mn austenitic steels behave as n-type and p-type semiconductors. Also, Mott–Schottky analysis indicated that the donor densities are in the range of 1021 cm-3.