Electrochemical Impedance Analysis of Effect of Surrounding Oxygen Concentration on Corrosion Resistance of Type 304 Stainless Steel

The effect of surrounding oxygen concentration on the passive film growth and the initiation and the progress of localized corrosion of type304 stainless steel under water film containing chloride ions was investigated by electrochemical impedance spectroscopy. The passive film became thicker, and the film resistance became smaller as oxygen concentration increased. After passive film breakdown, the increase in the oxygen concentration enhanced the oxygen reduction reaction. As a result, the dissolution of the metal substrate was more dominant than repassivation, and the progress of the localized corrosion accelerated.