Self‐Healing Corrosion Inhibition of Epoxy Polymer Composite Coatings Using Corrosion Inhibitor and Water‐Dispersed Nanoparticles

ABSTRACT Polymer composite coatings were fabricated using water‐dispersed nanoparticles and corrosion inhibitor. Carbon steel substrates were coated with a mixture of solvent‐based epoxy resin, water‐dispersed silica nanoparticles (NPs) with diameters from 45 to 180 nm, and magnesium phosphate powder (MP) particles with an average diameter of 1 µm. The coating containing 4 wt% NPs exhibited a resistance of more than 1200 Ω cm 2 after 24 h of immersion into a NaCl solution, which was approximately twice that of the NP‐free coating. The incorporation of larger NPs resulted in a resistance of 2200 Ω cm 2 after 24 h, representing the highest polarization resistance achieved in this study. This work is an investigation into the role of NPs and water within a polymer matrix. The NPs were preferentially distributed around the MP particles. In addition, the polymer coating containing 4 wt% water‐dispersed NPs showed lower levels of water uptake compared with that of the NP‐free coating. The self‐healing corrosion inhibition performance of the composite coating is attributed to the sustained release of corrosion inhibitor through uniformly distributed pores within the polymer matrix.