Effect of Oxidation Reduction Decontamination on Corrosion Performance of Sensitized 304L Stainless Steel

The corrosion resistance of sensitized 304L stainless steel after four kinds of decontamination processes such as alkaline potassium permanganate oxidation-ascorbic acid reduction (AP-A), acidic potassium permanganate oxidation-ascorbic acid reduction (NP-A), acid potassium permanganate oxidation-ascorbic acid and ethylenediaminetetraacetic acid reduction (NP-AE) and acidic potassium permanganate oxidation-oxalic acid reduction (NP-O) was investigated by weight loss test, scanning electron microscope observation and intergranular corrosion test. The results show that the mass loss of sensitized 304L stainless steel per unit area after cleaning by NP-A and NP-O decontamination processes was more, followed by NP-AE, and the mass loss per unit area of the sample after cleaning by AP-A process was the least. Compared with AP-A and NP-AE decontamination processes, the surface of the sample was more microporous after cleaning by NP-A and NP-O decontamination cleaning processes. The corrosion effect of alkaline potassium permanganate cleaning solution on 304L stainless steel was less than that of acidic potassium permanganate cleaning solution. Oxalic acid and ascorbic acid reducing agents were equivalent to corrosion of stainless steel. The sensitized 304L stainless steel did not undergo intergranular corrosion after being cleaned by four decontamination processes.