Atmospheric corrosion of low carbon steel in a coastal zone of Ecuador: Anomalous behavior of chloride deposition versus distance from the sea

Abstract

Atmospheric corrosion of low carbon steel exposed in a coastal tropical zone of Manabí, Ecuador, was determined. Specimens were exposed at six outdoor exposure sites located at different distances from the sea. The atmosphere is classified as coastal. Wind speed threshold for an increase in chloride deposition rate was determined. The behavior of chloride deposition rate versus distance from the sea is anomalous due to the presence of an estuary. Corrosion by weight loss was evaluated up to 1 year of exposure. Only a slight difference in atmospheric corrosion rate is noticed between wet and dry periods. Chloride deposition interaction with RH–temperature complex and with wind speed shows significant statistical influence on atmospheric corrosion of low carbon steel. Corrosivity category of the atmosphere high (C4) is the most predominant classification level in the zone. Prediction indicates corrosivity category high (C4) will remain up to 20 years of exposure. Different morphologies of corrosion products were identified by SEM. Lepidocrocite, goethite, magnetite, and akaganeite are the main crystalline phases determined by XRD. Protective ability index previously proposed for rust layers is not useful to apply in coastal sites.

Outdoor atmospheric corrosion of carbon steel and weathering steel exposed to the tropical‐coastal climate of Thailand

“…Characterization of corrosion products developed on CSs exposed facing the Caribbean Sea revealed additional akaganeite and magnetite to the well‐known main phases, lepidocrocite and goethite . Similar constituents were also observed in the corrosion products developed on low‐carbon steels exposed to the coastal‐tropical environment of Ecuador . It is worth mentioning that a correlation between CR and chloride deposition based on distance from the sea could not be drawn.…”

Atmospheric corrosion prediction: a review

“…In marine site with high amount of chloride deposition, β-FeOOH is produced as for chloride accelerative effect, while the main corrosion products are γ-FeOOH and α-FeOOH in exposure station with low or no chloride. Chloride mainly comes from the ocean and deicing (ISO, 2012a).The deposition rate of chloride from the ocean is affected by wind speed and wind direction (Cole et al 2003b;Li and Hihara 2014;Roberge et al 2002), distance from the coast (Cole et al 2003b;Cole et al 2003a;Guerra et al 2019), rainfall (Cole et al 2004a), temperature and humidity (Castaneda et al 2018;Cole et al 2003b), terrain (Cole et al 2003c;Cole et al 2004a) and other factors (Cole et al 2011). The influence of chloride has a significant relationship with the distance from the sea (Abbott 2008;Feliu et al 1999).…”

Comportamiento de la rugosidad superficial del acero luego de exposición natural en exterior e interior

“…Estudios realizados afirman que la humanidad se enfrenta a un grave problema causado por la contaminación ambiental, la corrosión de los metales, entre ellos, la corrosión atmosférica del acero, principalmente, en las zonas costeras. Muchas estructuras, se han construido con este metal, debido a su resistencia mecánica (Guerra et al 2018). Este es un fenómeno tan cotidiano como potencialmente destructivo, consumidor de recursos (Castaño et al 2007).…”