氧化还原去污对敏化304L不锈钢腐蚀性能的影响

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

采用失重试验、扫描电子显微镜观察、晶间腐蚀试验研究了敏化304L不锈钢经过碱性高锰酸钾氧化-抗坏血酸还原(AP-A)、酸性高锰酸钾氧化-抗坏血酸还原(NP-A)、酸性高锰酸钾氧化-抗坏血酸和乙二胺四乙酸还原(NP-AE)和酸性高锰酸钾氧化-草酸还原(NP-O)等4种去污工艺清洗后的耐蚀性。结果表明:敏化304L不锈钢经NP-A和NP-O去污工艺清洗后单位面积质量损失较多,其次是NP-AE,经AP-A工艺清洗后试样单位面积质量损失最少。与AP-A和NP-AE去污工艺相比,采用NP-A和NP-O去污清洗工艺清洗后试样表面的微孔更多。碱性高锰酸钾清洗液对304L不锈钢的腐蚀作用弱于酸性高锰酸钾清洗液对304L不锈钢的。草酸和抗坏血酸还原剂对不锈钢的腐蚀相当。敏化304L不锈钢经过4种去污工艺清洗后都未发生晶间腐蚀。

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-ascorhic 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.