ZrO2 nanoparticle encapsulation of graphene microsheets for enhancing anticorrosion performance of epoxy coatings

Abstract Graphene (rGO) is expected to enable an effective anti-corrosion barrier for metals owing to its chemical inertness and impermeability to gases and water. However, previous studies demonstrate limited anti-corrosion property and even corrosion enhancement of rGO on metal surfaces via micro-galvanic corrosion at the coating defects. To address the issue, in this work, sandwich-structured GZ microsheets is prepared by fully-covering the inert nanosized ZrO 2 on the double-side of 2D rGO, and then incorporated into epoxy coating as filler for protecting metallic substrate against corrosion. By virtue of structural, morphological and electrochemical characterizations and analysis, we find that 0.5 wt% GZ into epoxy coating enables to form uniform and defect-free anticorrosive coating, and hence improve corrosion-protective properties in 3.5 wt% NaCl solution. The resistance of 0.5 wt% GZ in the first day immersion is 81.8 GΩ·cm 2 , and the metal substrate is not corroded during immersion. The attached inert ZrO 2 shell on rGO effectively eliminates the rGO-metal/rGO connections, and hence prevents the local micro-galvanic corrosion.