Fabrication and characterization of graphene oxide/zirconium dioxide coatings produced by plasma electrolytic oxidation of Zr–1%Nb alloys

Abstract

In this investigation, a graphene oxide (GO)/zirconium dioxide (ZrO2) composite coating was fabricated on Zr–1%Nb alloy by plasma electrolytic oxidation (PEO) process to improve the wear behavior and reduce friction performance of the Zr alloy. The GO-containing composite coating was mainly composed of the monoclinic (m-ZrO2) and tetragonal (t-ZrO2) phases and had a higher intensity of surface reactions, density, and thickness than the GO-free coating. Furthermore, the GO-containing coating exhibited lower icorr and more positive Ecorr than the GO-free coating. The optimal amount of GO sheets for improving the composite coating properties was found to be 2 wt%; use of more than 2 wt% of the GO sheets, however reduced the coating properties due to the increase in the conductivity of the electrolyte, the creation of stronger micro-discharges on the surface of the coating, and their aggregation. Additionally, the GO sheets improved the hydrophobicity of the PEO coating.