Effect of copper content of AISI 1018 mild carbon steel on inhibition efficiency of imidazoline-based corrosion inhibitor in CO2-saturated brine

• Published in: Corrosion science 2023-11, Vol.224, p.111478, Article 111478
• Main Authors: Ho, Man Yi, Geddes, Jill, Hughes, Trevor L., Barmatov, Evgeny
• Format: Article
• Language: English
• Subjects: Adsorption kinetics; CO2 corrosion; Copper; Inhibition efficiency; Pre-corrosion
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2023.111478

The effects of the copper content (varied from 0.054 to 0.158 wt%) of AISI 1018 mild carbon steel and pre-corrosion treatments on the inhibition efficiency (η) of an imidazoline-based corrosion inhibitor was investigated in CO2-saturated brine under dynamic flow conditions at 70 °C. An increase in the initial copper content of the steel results in a decrease in η and a decrease in the rate of inhibitor adsorption due to the formation of a porous cementite film enriched with iron carbide and zero-valent copper, leading to an increase in galvanic corrosion. •Uninhibited corrosion of AISI 1018 resulted in corrosion products that are enriched with iron carbide and copper.•Cu0 enrichment was found on the cementite. The growing cementite and Cu0 deposition increased the galvanic corrosion.•Pre-corrosion reduces the efficiency (η) and lowers the adsorption kinetics of the imidazoline-based corrosion inhibitor.•η and the adsorption kinetics decreased with the increasing Cu content of the steel when the carbon content is >0.1 wt%.