Study on the Performance of Anodized Coating Prepared on 2024 Aluminum Alloy via Pulse Anodizing

Abstract

Different anodized coatings are prepared on the surface of 2024 aluminum alloy from different solutions by pulse anodizing to improve corrosion resistance and hardness. The thickness, roughness, structure, hardness, surface morphology, and corrosion resistance of different anodized coatings are studied. It is found that the anodized coating is composed of a porous layer on the surface and a nonporous barrier layer inside, showing the structure of [Formula: see text]-Al2O3 and [Formula: see text]-Al2O3. The anodized coating prepared from sulfuric acid solution mixed with oxalic acid and glycerol has a larger thickness and higher hardness. The surface morphology of the anodized coatings is porous. The thickness of the anodized coating prepared from oxalic acid solution is small and the pore distribution is not uniform. However, the anodized coating obtained from sulfuric acid solution mixed with oxalic acid and glycerol has the smallest average pore size of 6.38[Formula: see text]nm and ordered pore distribution, resulting in the best corrosion resistance.