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Effects of Hydrogen Peroxide on Corrosion of Stainless Steel, (II)

2004; Taylor & Francis; Volume: 41; Issue: 9 Linguagem: Inglês

10.1080/18811248.2004.9715560

1881-1248

Junichi Sugama, Shunsuke Uchida, Naoya YAMASHIRO, Yusuke Morishima, Tatsuya Hirose, Takahiro Miyazawa, Tomonori Satoh, Yoshiyuki Satoh, Koichi Iinuma, Yoichi Wada, Masahiko Tachibana,

Corrosion Behavior and Inhibition

A high temperature high pressure water loop, which can control H2O2 concentration with minimal oxygen (O2) coexistence, has been fabricated. In order to evaluate the effects of hydrogen peroxide (H2O2) on intergranular stress corrosion cracking. Not only static responses, i.e., electrochemical corrosion potential (ECP), of the stainless steel specimens exposed to H2O2 and O2 at elevated temperatures but also their dynamic responses, i.e., frequency dependent complex impedances (FDCI), were measured. The conclusions obtained by the experiments are as follows. 1. The ECP measured for the SUS 304 specimen exposed to 100ppb H2O2 reached the saturated level in 50h, showed a larger value than the specimen exposed to 200 ppb O2 and kept the same ECP level when the H2O2 concentration was decreased to 10ppb.2. The FDCI measured for the specimen exposed to 100 ppb H2O2 showed saturation in the low frequency semicircles; this behavior was determined by the electric resistance of the oxide film and caused by saturation of oxide film thickness. Behavior for the specimen exposed to 200 ppb O2 was determined by the resistance of oxide dissolution, which was much larger than that for the specimen exposed to H2O2 3. The ECPs of the specimens exposed to 200 ppb O2 after 200-h exposure to 100 ppb H2O2 were higher than those exposed to only 200 ppb O2 due to memory effects on oxide films. The specimens with pre-exposure to 200 ppb O2 did not show these memory effects.