Marine atmospheric corrosion of carbon steel in the tropical microclimate of Port Louis

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 (Formula presented.) and goethite ((Formula presented.)) as the predominant rust phases, with low percentages of magnetite ((Formula presented.)), akageneite (Formula presented.) and jarosite (Formula presented.). 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.