In-situ Synthesis of Corrosion Product-polymer Composites on Carbon Steel for Enhanced Erosion-corrosion Protection in CO₂ Corrosion Environments

Iron carbonate (FeCO₃) is a common corrosion product found on steel surfaces in carbon dioxide (CO₂)-containing aqueous environments. The formation of this corrosion product on the internal walls of carbon steel pipelines can suppress material dissolution by over an order of magnitude, providing an effective form of corrosion inhibition. One significant limitation associated with relying upon solely FeCO₃ to suppress material dissolution is its propensity to be locally removed by chemical or mechanical mechanisms. Here we report a novel strategy, implemented to generate a mineral-polymer nanocomposite layer in situ on an X65 steel surface in a CO₂ corrosion environment. The formation of the layer is achieved through the intercalation of functionalized polystyrene nanospheres into the developing FeCO₃ corrosion product. We demonstrate the feasibility of microsphere intercalation into the FeCO₃ crystal layer through appropriate functionalization. Such intercalation produces a composite structure that affords excellent corrosion protection analogous to ‘natural’ FeCO₃. Additionally, the composite FeCO₃ layer offers unique, enhanced physical-mechanical properties compared with naturally formed FeCO₃ layer. The process provides a potential means of improving the resistance of corrosion product layers to mechanical removal, and hence, the initiation of localized corrosion.