Abstract: Using polarization scan, electrochemical impedance spectroscopy and capacitance measurement, the correlation of corrosion resistance and semiconductor properties for electrochemically modified passive film formed on stainless steel in 0.5 mol•L^-1 NaCl solution was investigated, and the mechanism of the corrosion resistance of the electrochemically modified passive film was further studied. The result reveals that the films behave as n-type and p-type semiconductors in the potential range above and below the flat band potential, respectively. This behavior is assumed to be the consequence of the semiconducting properties of the iron oxide and chromium oxide regions which compose the passive film. Compared with natural passive film, electrochemically modified passive film has lower donor and acceptor density. The change of EFB was discussed as a function of anions adsorption on surface of passive film. With low donor and acceptor density and anion adsorption on surface of passive film, effectively preventing the adsorption of Cl^－ in passive film, the resistance to localize corrosion of passive film was greatly improved.

Key words: Stainless steel, Passive film, Corrosion resistance, EIS, Semiconductor property