Hydrogen Evolution Behavior in the Corrosion of Carbon Steel in Contact with Magnetite

Taniguchi, Naoki ; Tateishi, Tsuyoshi*; Fukudome, Kazuyuki*; Nishimura, Tsutomu*; Kawakami, Susumu

It has been reported that the corrosion of carbon steel is accelerated by a contact with magnetite, which is a representative corrosion product in low oxygen environment. It is important to clear the corrosion mechanism in the presence of magnetite for long term prediction of overpack corrosion. There are two possible cathodic reactions in the presence of magnetite coupled with anodic reaction. One is reduction of Fe(III) in magnetite, and the other is hydrogen evolution reaction. If the former dominate the cathodic reaction, corrosion acceleration will be stopped with the consumption of Fe(III). While, if the latter is the main cathodic reaction, corrosion acceleration is possible to be continued for a long time. In this study, corrosion rate and hydrogen evolution behavior were investigated by the immersion test of carbon steel in contact with dummy corrosion product to contribute to understanding the corrosion mechanism.