2014 Volume 63 Issue 4 Pages 109-115
Corrosion process of carbon steel in aqueous solution under the atmospheric environment and the oxygen depleted environment has been reviewed by focusing the corrosion film formed on carbon steel in neutral pH. In the neutral solution under the atmospheric condition which contains oxygen, the critical pH to form the corrosion film and the precipitation ratio of dissolved iron ions depending on pH and the parabolic growth rate law were discussed. Under oxygen depleted environment, H2O works as oxidizing agent to oxidize Fe to produce Fe3O4 film with production of H2 gas. At high temperatures, the dissolution process of the Fe3O4 film controls the corrosion rate, whereas, at lower temperatures, the film growth process controls the corrosion rate and a steady dissolution rate of Fe3O4 film determines the corrosion rate after long exposure time.
