Polyvinyl alcohol/polyethylene glycol composite hydrogel parceling on aluminum: Toward more robust micro-arc oxidation coatings

Micro-arc oxidation (MAO) technology is an important approach for improving the surface wear and corrosion resistance of aluminum (Al). It forms a dense ceramic oxide coating on the surface of Al through the cooperation of a special MAO power supply and electrolyte, thereby protecting the substrate. A hydrogel composed of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) prepared with an aqueous electrolyte was used to parcel Al disk before MAO. The hydrogel contains a large number of hydroxyl functional groups that increase the dielectric constant and surface activity of Al, resulting in a more dense and wear-resistant coating (Al-MAO-GEL) by the reaction. The surface appearance, elemental composition, distribution, concentration and phase compo-sition of the Al-MAO-GEL coating were analyzed using scanning electron microscope, energy-dispersive spec-troscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. The tribological properties and corrosion resistance of the coating were assessed by friction and corrosion tests, indicating that the Al-MAO-GEL coating was protective. This study provides insights into modifications to improve MAO coatings, thereby expanding the service life and possibilities of Al and Al alloy tribological components.