Preparation of MAO coatings doped with graphene oxide

ABSTRACT

Micro arc oxidation (MAO) coatings doped with graphene oxide (GO) were prepared on the 6061 Al alloy substrates in the electrolyte composed of an aqueous solution of sodium silicate (Na₂SiO₃·9H₂O, 20 g L⁻¹) and 100 mg L⁻¹ GO. The microstructure, mechanical property and tribological behaviour of the MAO + GO composite coatings were comparatively investigated. Results indicated that GO was easily dispersed into the solution for MAO coatings preparation. Little of GO in the composite coating was observed by field-emission scanning electron microscopy and energy dispersive spectrometer. This composite coating with increased proportion of α-Al₂O₃ phase still exhibited a porous microstructure like MAO coating but with an improved binding force, mechanical property and tribological behaviour. Furthermore, the tribological behaviour of this composite coating sliding against with hard alloy steel (YG6), silicon nitride (Si₃N₄) and High-carbon chromium bearing steel (GCr15) had been analysed.

KEYWORDS:

• 6061 Al alloy
• Microarc oxidation
• Graphene oxide
• Microstructure
• Properties

Acknowledgements

The authors gratefully acknowledge the financial support of the Natural Science Foundation of China (Grant No. 51571114 and 11504284) and Natural Science Foundation of Shaanxi Province (No. 2015JM5176).