Effect of $H_2O_2$ on the corrosion behavior of 304L stainless steel

Abstract

In connection with the safe storage of high level nuclear waste, effect of $H_2O_2$ on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without $H_2O_2$. The experimental results show that $H_2O_2$ increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as $H_2O_2$ concentration increased, indicating that pitting resistance was decreased by the existence of $H_2O_2$ in the electrolyte. These effects of $H_2O_2$ on corrosion of 304L stainless steel are considered to be similar to those of $\gamma$-irradiation. To compare the effects of $H_2O_2$ with those of $O_2$, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of $H_2O_2$ on the corrosion behavior were very similar to those of $O_2$ such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. Further, $H_2O_2$ played much greater role in controlling cathodic reaction rate in neutral water environment. In acid and alkaline media, potential shifts by $H_2O_2$ were restricted by the large current density of proton reduction and by the le Chatelier``s principle respectively.