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 (CeO2-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 CeO2-f reacts with epoxy resin by ring opening, CeO2-f and epoxy resin-treated CeO2-f (Ce CeO2-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 CeO2 surface by chemical bonding and underwent a ring-opening reaction with epoxy resin, thus, improving the compatibility of CeO2 in epoxy resin. NSST and electrochemical impedance spectroscopy results showed that the coatings containing 5% CeO2-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 CeO2-f as fillers with synergistic inhibition ability are promising for the protection of carbon steel.
