Atmospheric Corrosion of Low Carbon Steel in a Coastal Zone of Ecuador

Abstract

Atmospheric corrosion of low carbon steel exposed in a coastal tropical zone of Manabí, Ecuador with the presence of an estuary, was determined. Specimens of low carbon steel were exposed at six outdoor exposure sites located at different distances from the sea. The atmosphere was classified as coastal. The behavior of chloride deposition rate versus distance from the sea was anomalous due to the presence of an estuary. Corrosion by weight loss was evaluated up to 1 year of exposure. Corrosivity category of the atmosphere high (C4) is the most predominant classification level in the zone. Different morphologies of corrosion products were identified by SEM. Magnetite and akaganeite were the main crystalline phases observed. Protective ability index previously proposed for rust layers is not useful to apply in coastal sites.

Investigation of the salinization of steel surfaces in marine environment

“…Far more common than threshold values for surface contaminations are deposition rates of chloride (in mg/(m 2 d)) which are given in relevant standards, guidelines, and scientific publications . These values should enable the classification of different exposure and weathering sites with respect to chloride loading.…”

“…An extreme contamination in form of chlorides due to splash or spray water at the sea is not in the range of application of ISO 9223. The salinity of the atmosphere strongly depends on variables like, e.g., wind, distance to the coast, and the humidity–temperature complex influencing the transport of sea salt toward inland …”

“…Analysis of the literature shows numerous investigations for the maritime and marine coastal area . Publications dealing with the salinization of metal surfaces for offshore sites are scarce.…”