Enhanced corrosion resistance of atmospheric plasma-sprayed zirconia–GNP composite by graphene oxide nanoplatelet encapsulation

Abstract

The unique natural diffusion barrier property of graphene plays a crucial role in protecting the carbon steel substrates from corrosion, particularly using graphene oxide nanoplatelets (GNP)–zirconia (ZrO2) composites. In the present work, atmospheric plasma spraying (APS) technique has been used to coat both the spray-dried pristine ZrO2 and ZrO2–(0.5, 1.0, 1.5 and 2) wt% GNP composite on the carbon steel substrate. The retention of GNPs in the coating was confirmed using XRD, Raman spectroscopy, TEM, FE-SEM, and EDAX techniques. The corrosion properties of the coatings in 3.5 wt%NaCl electrolyte were studied using linear polarization resistance and electrochemical impedance spectroscopy technique. This reveals the enhanced charge transfer resistance, decreased corrosion current density and corrosion rate of ZrO2–GNP composite. Further, the corrosion rate of ZrO2–2 wt% GNP coating is 130 times less than the plasma-sprayed ZrO2. Compared to 0.5, 1.0 and 1.5 wt% GNP added zirconia coatings, ZrO2–2 wt% GNP displayed the highest stability up to 14 days in 3.5% NaCl electrolyte.