Comparative Characteristics of the Structure and Functional Properties of Coatings Formed on Aluminum Alloys 2xxx and 7xxx Series by the Method of Plasma Electrolytic Oxidation

-The structure and properties of coatings formed on 2xxx and 7xxx aluminum alloys by plasma electrolytic oxidation (PEO) performed under the same conditions have been studied. The substrate material is shown to substantially affect the quality, structure, and properties of formed coatings. Compared to the D16 T (4Cu, 1.4Mg wt %) alloy substrate, the V95 T1 (6.2Zn, 2.4Mg, 1.7Cu wt %) alloy substrate favors the formation of coatings with a more homogeneous composition and uniform thickness, which exhibit great cohesive and adhesive strength and mechanical and tribological properties. The adhesive failure of PEO coatings formed on the V95 T1 alloy occurs at a load of 63 N, which is substantially higher than the critical load (49 N) of coatings formed on the D16 T alloy. The maximum hardness of coatings formed on the V95 T1 alloy is 25 GPa, which exceeds that of coatings formed on the D16 T alloy and is equal to 20 GPa. The wear resistance of coating in water, which is formed on the V95 T1 alloy is 4.4 times higher compared to that of the wear-resistant coating formed on the D16 T alloy.