抄録
Corrosion rate of carbon steel in neutral water containing chloride ion is mainly controlled by dissolved oxygen. Hydrogen peroxide is generated under gamma ray irradiation and it will also affect corrosion. In this study, the effect of oxygen and hydrogen peroxide on corrosion rate of carbon steel in diluted artificial seawater was investigated by electrochemical methods. Diffusion coefficient and thickness of diffusion layer for oxygen and hydrogen peroxide were measured to estimate the diffusion limiting current density. Corrosion tests of carbon steel were also conducted in diluted artificial seawater containing oxygen and/or hydrogen peroxide at 323K, and the results were compared to the estimated diffusion limiting current density. The diffusion coefficient of hydrogen peroxide was about 0.8 times lower than that of oxygen, and the thickness of diffusion layer was almost equivalent between oxygen and hydrogen peroxide. Diffusion limiting current density of hydrogen peroxide was estimated to be 0.4 times lower than that of oxygen in the same concentration at 323K. Plot of corrosion rate with the sum of concentration of oxygen and 0.4 times concentration of hydrogen peroxide showed good correlation.
