Effect of cyanate ester and graphene oxide as modifiers on corrosion protection performance of epoxy composite coating in sulfuric acid solution

•An approach to improve the corrosion resistance of EP was proposed by incorporating CE and GO.•CE/EP coating was prepared by the chemical reaction between CE and EP.•GO improved the stability of the cross-linking network of CE/EP by covalent bonding.•EP modified by CE and 1 wt.% GO exhibited markedly enhanced and stable anti-corrosion properties. Cyanate ester (CE) and graphene oxide (GO) were employed to modify epoxy-based coating (EP) by chemical reaction, and related corrosion protection behaviors were investigated in sulfuric acid solution. Epoxy coating modified by cyanate ester (CE/EP) displayed slower electrolyte diffusion. Further, incorporating 1 wt.% GO into CE/EP (1 wt.% GO/CE/EP) significantly enhanced the polymer stability and anti-corrosion properties. Compared with CE/EP without GO, the low frequency impedance increased by 5 orders of magnitude after 71 days of immersion. Meanwhile, the 1 wt.% GO/CE/EP coating was morphologically unaltered, and no obvious corrosion was detected. Results verified that EP modified by CE and 1 wt.% GO exhibited superior anti-corrosion performance.