The Effects of Rare Earth Elements on Corrosion Resistance of Sol-gel Coatings for 2024 Aluminum Alloy

摘要

Rare-earth modified coatings on 2024 aluminum alloy were prepared by sol-gel methods, aiming at improving the corrosion resistance with the environmental friendly features. The investigation put emphases on the effects of rare-earth additives on corrosion resistance and microstructure of sol-gel coatings. The results revealed that coated samples containing 2g·L~(-1) rare-earth not only delayed the incubation period of corrosion, but also hindered the development of it, and their corrosion rate decreased 80.3% compared with the bare ones and was 15.9% than the rare-earth free coated ones. The action of rare-earth on morphology and microstructure of sol-gel coatings for 2024 Al alloy was studied by SEM. High density good cohesion, and intact coverage were showed clearly ,which provided a reliable proof of the reformative effects of rare-earth additives.