▎ 摘　　要

With the development of ultradeep oil and gas reservoirs, the service environment for tubing and casings is increasingly worse, resulting in higher requirements for the internal coatings, while reduced graphene oxide (rGO) is conducive to enhancing the corrosion resistance of the coatings to a certain extent. In this paper, rGO was first modified by the coupling agent KH-550 (namely, MrGO), and the physical and chemical properties (dispersibility, thermal stability, contact angle, and adhesion) of the MrGO/epoxy coatings with different MrGO contents (0.5 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, and 4 wt.%) were analysed. The corrosion resistance behaviour was studied by electrochemical techniques in CO2-Cl- environments. The results showed that the coupling agent KH-550 was better grafted with rGO and that the diffusivity of MrGO in the MrGO/epoxy coatings was significantly improved. With an increase in the MrGO content, the physical and chemical properties of the MrGO/epoxy coatings were considerably enhanced, and the corrosion resistance first increased and then decreased; among them, the thermal stability, friction coefficient, impact performance, adhesion, and corrosion resistance of the MrGO/epoxy coatings were best when the content of MrGO was 3 wt.%. Finally, a novel corrosion resistance mechanism was proposed for the MrGO/epoxy coatings. Thus, this work provides theoretical support for the development of new heavy corrosion coatings.