Properties of passive film formed on 316L / 2205 stainless steel by Mott-Schottky theory and constant current polarization method

Semiconductor properties of the passive films formed on 316L and 2205 stainless steel were studied by Electrochemical Impedance Spectroscopy (EIS) in the high-temperature acetic acid. The results showed that the corrosion resistance of 2205 was higher than that of 316L, and the passive films formed on 316L and 2205 stainless steel showed p-type and n-type semiconductor behavior, respectively. Destruction and self-repairing of passive films were studied by using the constant current polarization method. The results showed that for 316L, the self-repairing process would occur when the destruction was lower than the critical extent or it would not do; for 2205, the self-repairing process only happened in a short time when the destruction was in the same extent as 316L.