Improving the quality of nanocrystalline MgAl2O4 spinel coating on graphite by a prior oxidation treatment on the graphite surface

This paper aims to report the effect of surface oxidation treatment on graphite flakes and its effect on the improvement of MgAl2O4 spinel coating developed by sol–gel citrate process. The graphite surface was oxidized by hydrogen peroxide and the coating was subsequently applied. The coating structure, water-wettability and oxidation resistance of coated samples were taken as criteria to evaluate the coating integrity. It was clarified that the oxidation treatment developed hydrophilic functional groups on graphite surface. This helped the formation of an even and smooth MgAl2O4 spinel coating texture on graphite flakes. The water-wettability and oxidation resistance were also found to be improved significantly compared to non-treated samples. The results were supported by thermogravimetric analysis, contact angle and zeta-potential measurements.