Noticeable localized corrosion of solid boric acid on 304 stainless steel

Abstract

With the aim to determine the potential corrosion effects of solid boric acid (BA) on light water reactors or other BA-involved equipment, the corrosion behaviors of solid BA on 304 stainless steel (SS) at different temperatures were investigated. Upon comparing the corrosion behaviors of solid BA at different temperatures, significant localized corrosion was observed on 304 SS surfaces at 150 °C following 90-day. This localized corrosion exhibited a characteristic pattern of scattered corrosion craters including B-containing Cr-rich oxides. These oxides were found to originate within micro-cracks, gradually evolving into scar-like protrusions within the craters. The proposed corrosion mechanisms entail the interactions between solid BA and chromium oxides/hydroxides, leading to the formation of B-containing Cr-rich oxides. Our findings offer insights into potential corrosion incidents and protective strategies for industries dealing with solid BA.

Keywords

• Localized corrosion
• Solid boric acid
• 304 stainless steel