Marine atmospheric corrosion of carbon steel in the tropical microclimate of Port Louis. Issue 9 (21st March 2022)

• Record Type: Journal Article
• Authors: Seechurn, Yashwantraj; Surnam, Baboo Y. R.; Wharton, Julian A.
• Is Part Of: Materials and corrosion. Volume 73:Issue 9(2022)
• Page Start: 1474
• Page End: 1489
• Publication Date: 2022-03-21
• Subjects: atmospheric corrosion -- carbon steel -- rust -- SEM -- weight loss -- X‐ray diffraction; Materials -- Periodicals; Metals -- Periodicals; Corrosion and anti-corrosives -- Periodicals; 620.1122305
• DOI: 10.1002/maco.202112871
• Languages: English
• ISSNs: 0947-5117

Abstract

Abstract: The atmospheric corrosion performance of S235 carbon steel is assessed when exposed to the tropical/marine aerosol pollutants of Port Louis, Mauritius. Port Louis is situated on the northwest coast and has a distinct microclimate, leading to major atmospheric corrosion concerns. In addition, sulphur dioxide emissions from three heavy oil‐fired power stations complicate corrosion prediction within the region. Mass‐loss analysis shows distinctive corrosion progression behaviours linked to the environmental and geographical variables. The formation of porous surface layers leads to a continuous increase in metal dissolution during the electrochemical process. The surface analysis reveals lepidocrocite ( γ ‐ FeOOH ) $\left(\gamma \mbox{-} \text{FeOOH}\right)$ and goethite ( α ‐ FeOOH $\gamma \mbox{-} \text{FeOOH}$ ) as the predominant rust phases, with low percentages of magnetite ( Fe 3 O 4 ${\text{Fe}}_{3}{{\rm{O}}}_{4}$ ), akageneite ( β ‐ FeOOH ) $\left(\beta \mbox{-} \text{FeOOH}\right)$ and jarosite ( K Fe 3 ( OH ) 6 ( SO 4 ) 2 ) $({\rm{K}}{\text{Fe}}_{3}{(\text{OH})}_{6}{({\text{SO}}_{4})}_{2})$ . A key insight in the S235 atmospheric corrosion involves two stages: the early rapid corrosion stage followed by a slow stage of linear or power‐law corrosion kinetics due to the formation of stable rust phases. Abstract : This study helps to understand the corrosion kinetics of carbon steel and to determine any association between the environment and the rust content in a corrosion layer formed in a marine atmosphere in which airborne salinity is low. The results show that marine atmospheric corrosion rate is also dependent on factors other than airborne salinity while the formation of akaganeite, magnetite and other insoluble compounds at the coastal sites is sparse.