Cerium dioxide modified with fumaric acid as corrosion inhibitor for epoxy coatings on Q235

Purpose The purpose of this study is to modify cerium dioxide with fumaric acid (CeO 2 -f) to improve its compatibility and dispersibility in epoxy resin and to investigate the effect of the content on the coating performance. Design/methodology/approach To investigate whether CeO 2 -f reacts with epoxy resin by ring opening, CeO 2 -f and epoxy resin-treated CeO 2 -f (Ce CeO 2 -f/EP) were analyzed by infrared radiation (IR), X-ray diffraction (XRD) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis). To reveal the effect of different content on coatings properties, neutral salt spray test (NSST) and electrochemical test were performed. Findings The results of IR, XRD, X-ray photoelectron spectroscopy and UV-Vis indicated that fumaric acid attached to the CeO 2 surface by chemical bonding and underwent a ring-opening reaction with epoxy resin, thus, improving the compatibility of CeO 2 in epoxy resin. NSST and electrochemical impedance spectroscopy results showed that the coatings containing 5% CeO 2 -f exhibited the optimal corrosion resistance. The reason is that a dense conversion film was established on the substrate surface. Originality/value The epoxy coatings using CeO 2 -f as fillers with synergistic inhibition ability are promising for the protection of carbon steel.