Increased corrosion protection of electrophoretic epoxy coatings through graphene oxides
The use of amino-functionalised graphene oxides has significantly improved the corrosion protection behaviour of electrophoretic epoxy coatings.
In a cooperation between the Southwest Petroleum University, Chengdu, the Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province and the China National Petroleum Corporation, the influence of functionalising a graphene oxide surface with polyethyleneimine (PEI) was investigated. The graphene oxide surface was refined with PEI and the resulting PEI-GO/EP composite coating was successfully deposited on carbon steel by cathodic dip coating (C-EPD).
Various methods such as zeta potential, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), atomic force microscopy (AFM) and thermogravimetric analysis (TGA) were used for characterisation. The dispersibility of PEI-GO in electrophoretic epoxy paint was analysed using TEM, and the fracture surface morphology of the coatings was observed using a scanning electron microscope (SEM).
Electrochemical impedance spectroscopy (EIS) was used to determine the anti-corrosion properties of the composite material. It was shown that the impedance modulus of the PEI-GO/EP composite coating is two orders of magnitude higher than that of the pure epoxy coating. Therefore, the corrosion protection has been significantly increased.
Source: Journal of Coatings Technology and Research 21, 761–771 (2024).
