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 (ZrO<inf>2</inf>) composites. In the present work, atmospheric plasma spraying (APS) technique has been used to coat both the spray-dried pristine ZrO<inf>2</inf> and ZrO<inf>2</inf>–(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 ZrO<inf>2</inf>–GNP composite. Further, the corrosion rate of ZrO<inf>2</inf>–2 wt% GNP coating is 130 times less than the plasma-sprayed ZrO<inf>2</inf>. Compared to 0.5, 1.0 and 1.5 wt% GNP added zirconia coatings, ZrO<inf>2</inf>–2 wt% GNP displayed the highest stability up to 14 days in 3.5% NaCl electrolyte. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.