Electrochemical Impedance Spectroscopy Study of H₂O₂ Interaction With Γ-FeOOh Single-phase Films on the Gold Electrodes

Abstract

Carbon steel is a common component of structural materials used in nuclear power reactors and other nuclear facilities. The corrosion of carbon steel is strongly influenced by surface oxide film composition and morphology due to considerable variation in the oxide reactivity and solubility. Despite extensive studies on the mechanism of carbon steel corrosion, the existence and the role of γ-FeOOH, particularly in pitting or stress corrosion, are still debated. Our research goal is to determine how radiolytic oxidants, such as H₂O₂, will interact with oxide-covered steel surfaces and what influence this will have in steel corrosion kinetics. In the current study, the interaction of H₂O₂ with single-phase γ-FeOOH films chemically deposited on gold electrodes is investigated as function of pH and H₂O₂ concentrations, using electrochemical techniques ranging from corrosion potential measurements, cyclic voltammetry and electrochemical impedance spectroscopy. The results are then compared with those for H₂O₂ interaction with oxide-covered carbon steel.