High concentration of organic solvents in aluminum MAO: A study of structural and tribological property

Ceramic coatings were prepared on the surface of 6061 aluminum alloy using micro arc oxidation (MAO) with high concentration of polyethylene glycol (PEG200) as electrolyte. In this paper, the real-time discharge process of MAO in different volume ratios of PEG200 electrolyte was recorded and the coatings were characterized as well as tested for abrasion and corrosion resistance. The results show that the coatings prepared in 50% PEG200 electrolyte produce more hard alumina crystalline phases with better surface lubrication and wear resistance, but higher porosity reduces their corrosion resistance. This is thought to be related to adsorption of molecular chains as well as soft spark discharge. By preparing high quality coatings in high concentrations of organic solvents, a feasible solution is provided to improve the structure and properties of the coatings.