Assessment of atmospheric corrosivity in coastal zones: Case study in port Lopez, Manabí, Ecuador

This manuscript investigates the atmospheric corrosion of carbon steel in Puerto Lopez, a coastal region in Manabí Province, Ecuador. For the study, six outdoor exposure sites (OES) were strategically placed at different distances from the coast to evaluate the impact of meteorological factors on the chloride deposition rate (Cl⁻DR) and how proximity to the coast could influence atmospheric corrosivity to carbon steel. It identified a critical threshold for the monthly average wind speed that escalates Cl⁻DR, noted as one of the lowest globally. The findings revealed a medium corrosivity category (C3) for carbon steel in the inland OES, suggesting the significant role of high relative humidity (RH) typical of the area in possibly reducing Cl⁻DR through saline dissolution. Moreover, the interaction between high RH and Cl⁻DR could markedly diminish oxygen's solubility in water collected in oxide layer interstices and on the carbon steel surfaces, potentially affecting the cathodic oxygen reaction. Nonetheless, the study confirms the continuing influence of Cl⁻DR on the atmospheric corrosion of carbon steel. Predictive corrosivity categories for carbon steel in this coastal environment span from two to twenty years across the OES, underlining the critical need for understanding and mitigating corrosion in similar settings.