Effect of Dissolved Ozone on Corrosion Behavior of Stainless Steels in Artificial Seawater

Abstract

Abstract Corrosion resistance of austenitic stainless steels (SS) in artificial seawater containing 0.2 mg/L to 0.4 mg/L dissolved ozone (O3) was investigated. According to cyclic polarization data, types 304 SS (UNS S30400) and 316 SS (UNS S31600) were resistant to pit initiation after 8 weeks of exposure to ozonated artificial seawater. However, when crevices existed, crevice corrosion was more severe in ozonated vs aerated artificial seawater. Maximum crevice corrosion penetration rates of 8 mm/y and 5 mm/y (0.315 in./y and 0.197 in./y) were recorded for types 304 and 316 SS, respectively, in ozonated artificial seawater compared to only 0.4 mm/y to 0.5 mm/y (0.016 in./y to 0.020 in./y) under aerated conditions. Mixed-potential analysis of anodic and cathodic polarization predicted crevice corrosion rates for type 316 SS in excellent agreement with the immersion sample data. Highly alloyed nickel-, chromium-, molybdenum-, and nitrogen-bearing austenitic SS were resistant to crevice corrosion in aerated...