Effect of surface pre-treatment by silanization on corrosion protection of AA2024-T3 alloy by sol-gel nanocomposite coatings

Corrosion protection behavior of sol-gel coating doped with cerium nitrate was investigated on AA2024. The sol-gel layer composed of methyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane and colloidal silica. The performance of the sol-gel coating with and without surface silanization was evaluated using electrochemical techniques and neutral salt spray test. The morphology and composition of the coatings were examined by FESEM and EDX techniques before and after corrosion. Electrochemical studies indicated that cerium doped sol-gel coating with the additional APTEOS layer provided better corrosion resistance even after 168 h of exposure among all the developed coatings. Surface silanization provided additional protection to the metal surface.