Carbon dioxide (CO2) internal corrosion of carbon steel pipelines remains a major issue that is typically mitigated via the addition of corrosion inhibitors. In specific operational environments, a protective natural corrosion product layer known as iron carbonate (FeCO3) can evolve on internal pipeline walls, providing comparable inhibition efficiency to that achieved from typical oilfield surfactant inhibitors. However, in some instances, partial coverage can initiate localized corrosion. In our previous work, we demonstrated the ability of Poly (allylamine hydrochloride) (PAH) to act synergistically with FeCO3 when the corrosion product exhibits partial coverage of X65 carbon steel surfaces in an aqueous CO2 corrosion environment.1  In this work, we employ Rotating Cylinder Electrode (RCE) tests coupled with electrochemical measurements to study the FeCO3-PAH hybrid structure in a hydrodynamic environment. The general and localized corrosion behavior, as well as surface properties of a naturally formed FeCO3 and the FeCO3-PAH hybrid layers are characterized, employing interferometry and scanning electron microscopy (SEM) coupled focused ionic beam (FIB).

Subject
Pits, Steel surfaces, Corrosion rate, Carbon steel surfaces, Precorrosion, Hydrodynamics, Corrosion products, Polymers, Corrosion inhibitors, Surface layers, Carbon steel, Corrosion protection, Localized corrosion
Keywords:
CO2 corrosion, carbon steel, iron carbonate, corrosion products, biodegradable PAH polymer, hybrid layer
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2023
Association for Materials Protection and Performance (AMPP)
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