Effects of γ-radiation versus H2O2 on carbon steel corrosion

The effect of ionizing radiation on steel corrosion is an important materials issue in nuclear reactors. In the presence of ionizing radiation water decomposes into both oxidizing and reducing species (e.g., (OH)-O-center dot, H2O2, O-center dot(2)-) whose net interactions with steels are not fully understood. The effect of radiation on the corrosion kinetics of carbon steel has been studied at pH 10.6 and room temperature, using electrochemical and chemical speciation analyses. The present study investigates the effect of gamma-radiation on carbon steel corrosion and compares it with that of chemically added H2O2, which is considered to be the key radiolytically produced oxidant at room temperature. Various oxide films were pre-grown potentiostatically on carbon steel electrodes, and then exposed to either gamma-radiation at a dose rate of similar to 6.8 kGy h(-1) or to H2O2 in a concentration range of 10(-6) to 10(-2) M. The corrosion kinetics were studied by monitoring the corrosion potential (E-CORR), and periodically performing linear polarization (LP) and electrochemical impedance spectroscopy (EIS) measurements. (C) 2009 Elsevier Ltd. All rights reserved.