著者

石見 清隆 井田 義明 津高 文幸 杉本 克久

出版者

一般社団法人 表面技術協会

雑誌

表面技術 (ISSN:09151869)

巻号頁・発行日

vol.67, no.3, pp.150-158, 2016-03-01 (Released:2017-03-01)

参考文献数

12

被引用文献数

1 2

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Anodic polarization curves of electro-polished Type 304 stainless steel were measured in organic acid solutions of eight types to develop a safe and environmentally friendly passivation treatment. The pitting potentials of the steel passivated in the solutions were examined in a deaerated 3.5%NaCl solution. Among the organic acid solutions, 8%DL-malic acid, 8%citric acid, 8%L-tartaric acid and 8%glucono-δ-lactone were found to be suitable as treatment solutions because of the low current densities(<0.02 A・m-2)of the passive state and high pitting potentials(>700 mV vs. Ag/AgCl(sat. KCl))of the passive films. Passive films formed on Type 304 stainless steel by natural immersion into 8%DL-malic acid+0.98%H2O2, 8%citric acid+0.98%H2O2, 8%L-tartaric acid+0.98%H2O2 and 8%glucono-δ-lactone+0.98%H2O2 showed high pitting potentials(>1000 mV)in NaCl solutions of 3.5% - saturation concentration. For solutions containing H2O2, the pitting-potentialraising effects were greater on an electro-polished surface than on a buffer(#400)-polished surface.