Preparation of Graphene‐Reinforced Epoxy Nanocomposite Coating With Enhanced Anticorrosive Properties for Heat Exchangers

Abstract

Heat exchangers in the petrochemical industry face severe corrosion risks. In this study, a graphene‐reinforced epoxy (Gr‐EP) nanocomposite coating was prepared by incorporating 0.3 wt% of vapor‐phase synthesized graphene into an epoxy matrix along with two‐dimensional fillers (graphite, mica, and talcum powder) and functional pigments (chromium oxide green and red micaceous iron oxide). The Gr‐EP coating exhibited visibly fewer internal defects, improved adhesion, and better mechanical properties than both the epoxy coating without graphene and the commercial epoxy primer. Electrochemical tests revealed that the Gr‐EP coating exhibited a low‐frequency impedance modulus of 2.90 × 10 9  Ω·cm 2 . Moreover, the Gr‐EP coating remained intact without blistering or rusting after 6000 h of salt spray testing. The excellent anticorrosion performance is attributed to a synergistic physicochemical mechanism involving the physical barrier effect of the two‐dimensional nanomaterials and the passivation effect of the active fillers. In addition, owing to the high thermal conductivity and effective integration of the graphene nanosheets, the Gr‐EP coating also showed improved thermal properties. This work provides a promising and practical route toward durable corrosion protection for heat exchangers.