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Effects Of Hydrogen Peroxide On Intergranular Stress Corrosion Cracking Of Stainless Steel in High Temperature Water, (IV)

2001; Taylor & Francis; Volume: 38; Issue: 3 Linguagem: Inglês

10.1080/18811248.2001.9715020

1881-1248

Yoichi Wada, Atsushi Watanabe, Masahiko Tachibana, Kazushige Ishida, Naohito Uetake, Shunsuke Uchida, Kazuhiko AKAMINE, Mitsuru Sambongi, Shunichi Suzuki, Kenkichi Ishigure,

High Temperature Alloys and Creep

Abstract In order to determine the effects of hydrogen peroxide on electrochemical corrosion potential (ECP) of type 304 stainless steel (SUS304), ECPs were measured using a high temperature, high pressure water loop with polytetrafluoroethylene (PTFE) inner liner at controlled hydrogen peroxide concentration. It is observed that the ECP of SUS304 exposed to hydrogen peroxide is higher than that when exposed to oxygen at the same oxidant concentration. The ECP shows a hysteresis pattern for its concentration dependency. Those results were attributed mainly from the chemical form of oxide film on stainless steel specimens. The oxide film was affected by the corrosive circumstances. Hematite (α-Fe2 O3) was observed for the specimens exposed to hydrogen peroxide, while Fe3O4 was a main oxide when exposed to oxygen. The difference of the anodic polarization curves between O2 and H2O2 environments was caused by the difference of the stability between α-Fe2O3 and Fe3O4. Since the α-Fe2O3 is reduced to the Fe2+ when hydrogen is added to water, the ECP decreases with decreasing oxidant concentration without showing the hysteresis that keep the ECP higher value. KEYWORDS: BWRwater chemistryintergranular stress corrosion crackingstainless steelselectrochemical corrosion potentialhydrogen peroxideoxide filmHWC