Mechanistic modelling of atmospheric corrosion of carbon steel in Port-Louis by electrochemical characterisation of rust layers

Abstract

S235 structural steel was exposed for 14 months at six locations in the marine/urban atmosphere of Port-Louis, distinguished by the surrounding bay and mountains. An unusual geospatial variability in terms of chloride deposition rate (7.8–54.3 mg m−2 d−1), SO2 level (1.2–2.4 mg m−2 d−1) and corrosion rate (77.6–189.2 g m−2 y−1) was observed. Electrochemical techniques, supported by mass loss and surface analysis, provide insights into environment-specific corrosion mechanisms, with the occurrence of anomalous diffusion at the aggressive exposure sites. Rust layer corrosion resistances ranged between 4 and 113 Ω cm2.

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