The method for determining the repassivation potential for corrosion crevice of stainless steel is defined by JIS, but that of Alloy600 is not defined yet. In this paper, the method for determining the repassivation potential was considered based on the experiments with Alloy600 of nuclear constituent material by reference to JIS and intended to contribute to the establishment of it. In preparation for measuring the repassivation potential, the pitting potential dependence of Cl- concentration is measu...
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Study on the electrochemical method for determining the repassivation potential for corrosion crevice of Alloy600.

Crevice corrosion has been concerned in the Fukushima Daiichi Nuclear Power Station, since seawater was injected to make up water level as part of the emergency action. To evaluate structural integrity, it is important to inves tigate whether crevice corrosion occurred. The purpose of this study is to investigate conditions of crevice corrosion initiation and repassivation of SUS304L. SUS304L specimens with acrylic crevice were held at constant electr ochemical potentials in 1000ppm Cl- solution. It was in...
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Evaluation of crevice corrosion initiation condition and repassivation condition of SUS304L

Austenitic stainless steels are widely used as structural materials in many industries. However, stainless steels are susceptible to crevice corrosion in the solution including chloride ions. In this paper, at first, the most inhibitive anion against corrosion was investigated by anodic polarization measurement of type 316L stainless steel in the solution containing Cl- with candidate inhibitive anions (WO42-, MoO42-, VO3-). MoO42- was adopted as the most inhibitive anion in this study. Next, the effec...
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Effect on critical potentials for crevice corrosion initiation and repassivation of stainless steel by addition of inhibitive anion

When crevice corrosion occurs in Cl- containing solutions, Cl- concentration in the crevice increases by a few orders of magnitude due t o potential gradient. This is one of the reasons why localized corrosion takes place in a crevice. If there are non-aggressive anions ( such as MoO42-) coexist in the bulk with Cl-,it is expected that the non-aggressive anions migrate into the crevice competitively with C l- and it helps to improve the crevice environment. The purpose of this study is to investigate the e...
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Effects of non-aggressive anions as a mitigation measure to crevice corrosion in a chloride containing environment