Abstract: The semi-conductive performances of hot growth film on 316L stainless steel were studied by means of electrochemical impedance spectroscopy(EIS) and Mott-Schottky analysis. The chemical compositions of the hot growth films were detected by X-ray photoelectron spectroscopy(XPS). The results show that the transfer resistance and film resistance increase with increasing temperature to 400 °C, then they decrease sharply with further continuously increasing temperature. Formation time plays an important role in determining the electron properties of the hot growth film, when formation time reaches to 1 d, the transfer resistance and film resistance reach to the maximum value. Hot growth film has better anticorrosion behaviour in bicarbonate/carbonate solution containing chloride ions or sulfide ions. Mott-Schottky analysis reveals that hot growth film has n-p type semi-conductive property. XPS results show that the hot growth film is mainly composed of the inner chromium oxide and the outer iron oxide.

Key words: Stainless steel, Electrochemical impedance spectroscopy(EIS), Mott-Schottky, X-Ray photoelectron spectroscopy(XPS), Passive film