Facile Enhancement of Corrosion, Wear and UV Aging Resistance of Epoxy Composite Coatings via Graphene Oxide Incorporation.

UV aging, corrosion and wear resistance of epoxy (EP) coatings are all critical for their long-term service in outdoor environments. In this work, graphene oxide (GO) was used as a multifunctional additive in epoxy coatings to improve these properties. Owing to its two-dimensional sheet-like nanostructure and abundant oxygen-containing functional groups, which enable a favorable interface with the epoxy matrix, incorporating GO into epoxy coatings endows the coating with multiple enhanced performances, including anti-corrosion performance, UV resistance, wear resistance, and adhesion to metal substrates. The resulting GO/EP composite coating exhibits higher adhesion strength (15.08 MPa) than that of neat epoxy coating (12.02 MPa), and delivers excellent corrosion resistance, with a corrosion current density of 4.69 × 10-11 A·cm-2 which is as low as 1/3 that of the neat epoxy coating after 25 days of immersion in NaCl solution. Notably, after multiple cycles of thermal cycling testing, the coating maintains an impedance ~40 times higher than that of neat epoxy coating. After UV aging testing, comparing to neat EP coating, the GO/EP coating experiences far less degradation in gloss, water resistance, corrosion resistance and bonding strength to steel substrates. In addition, tribological tests confirmed that GO/EP has improved wear resistance compared with neat epoxy coating and the wear rate of epoxy coating was reduced by ~30% with incorporation of only 0.1%wt GO. This study provides a promising strategy for developing durable protective coatings for practical applications.