Engineering of corrosion product-polymer hybrid layers for enhanced CO2 corrosion protection of carbon steel part two: Computational investigation and surface characterisation

• Published in: Polymer (Guilford) 2022-05, Vol.250, p.124776, Article 124776
• Main Authors: Shaikhah, Dilshad, Ritacca, Alessandra Gilda, Ritacco, Ida, Matamorose-Veloza, Adriana, Taleb, Wassim, Mohamed-Said, Maalek, Cowe, Bruce, Neville, Anne, Camellone, Matteo Farnesi, Barker, Richard
• Format: Article
• Language: English
• Subjects: Adsorption energy; Carbon dioxide; Carbon steel; Carbon steels; Chemical properties; CO2 corrosion; Computer applications; Corrosion; Corrosion environments; Corrosion inhibitors; Corrosion prevention; Corrosion products; Density functional theory; Fourier transforms; Hybrid layer; Hybrid structures; Infrared spectroscopy; Interfacial surface; Iron carbonate; Localized corrosion; Photoelectron spectroscopy; Photoelectrons; Polymers; Scanning electron microscopy; Spectrum analysis; Steel; Steel pipes; Surface properties; Surfactants; X ray photoelectron spectroscopy; X-ray diffraction
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2022.124776

Carbon dioxide 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 corrosion inhibitionefficiency to that achieved from surfactants. However, in some instances, incomplete corrosion product coverage can initiate localised 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 ×65 carbon steel surfaces in an aqueous CO2 corrosion environment. In this work, we employ density functional theory (DFT) to show that PAH is able to coordinate with both FeCO3 and the bare carbon steel surface, producing a FeCO3-PAH hybrid structure. The surface and chemical properties of a naturally formed FeCO3 and the FeCO3-PAH hybrid layers are characterised employing scanning electron microscopy (SEM) coupled with focused ionic beam (FIB), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD) and X-ray photoelectron spectroscopy (XPS). [Display omitted] •The PAH molecules adsorb onto the carbon steel surface and corrosion product (FeCO3) via chemisorption and physisorption.•The PAH molecules interact with FeCO3 through coordination and hydrogen bonding producing a hybrid layer.•The PAH centres of interaction with film-free carbon steel and FeCO3 film are protonated and neutral amine groups.•The crystal structure and layer thickness of FeCO3 and FeCO3-PAH hybrid layers are characterised and compared.