Corrosiveness of Decontamination Solutions to Sensitized AISI 304 Stainless Steel

Abstract An experimental study of the corrosiveness of citric acid, oxalic acid, and EDTA mixtures to sensitized AISI 304 stainless steel (SS) was conducted. In initial tests, the corrosivity of various solutions at 125 C was assessed by measuring anodic polarization curves and estimating corrosion current densities (CDs), critical CDs for passivity, and passivation CDs. Based on the electrochemical results, solutions were ranked from highest to lowest according to their corrosiveness when applied to sensitized AISI 304 SS as follows: citric acid/oxalic acid, citric acid/oxalic acid/EDTA, and citric acid/ EDTA. Scanning electron microscopy (SEM) and metallographic examinations of specimens exposed at rest potential to solutions of varying corrosiveness show that intergranular attack (IGA), IGA with pitting at grain boundaries, and general pitting occurred only in samples immersed in solutions containing oxalic acid. No surface attack was detected in specimens immersed in citric acid/EDTA mixtures. These r...