Structure and properties of ceramic coatings formed on aluminum alloys by microarc oxidation
(1.黑龙江省哈尔滨市黑龙江科技学院材料科学与工程学院
2.College of Materials Science and Engineering, Heilongjiang Institute of Science and Technology,Harbin 150027, China)
2.College of Materials Science and Engineering, Heilongjiang Institute of Science and Technology,Harbin 150027, China)
Abstract: The thick and hard ceramic coatings were deposited on 2024 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 show that the ceramic coating is mainly composed of α-Al2O3 and γ-Al2O3. During oxidation, the temperature in the microarc discharge channel is very high to make the local coating molten. From the surface to interior of the coating, microhardness increases gradually. The microhardness of the ceramic coating is HV1 800, and the microarc oxidation coatings greatly improve the antiwear properties of aluminum alloys.
Key words: 2024 alloy; ceramic coatings; aluminum alloys; microarc oxidation; wear resistance; mechanical properties