Structure and properties of ceramic coatings formed on 7N01 alloys by microarc oxidation

In this paper, thick and hard ceramic coatings were deposited on 7N01 Al alloy by microarc oxidation in the electrolytic solution. Microstructure, phase composition and wear resistance of the oxide coatings were investigated by SEM, XRD and friction and wear tester. The microhardness and thickness of the oxide coatings were measured. The results showed that the ceramic coating is mainly composed of α-Al2O3and γ-Al2O3. During oxidation, the temperature in the microarc discharge channel was very high to make the local coating molten. From the surface to the interior of the coating, microhardness increase gradually. The microhardness of the ceramic coating was HV1300, and the microarc oxidation coatings greatly improve the antiwear properties of aluminum alloys.