Effects of cerium salts on corrosion behaviors of Si-Zr hybrid sol-gel coatings

Abstract The present work examines the effects of cerium salts on corrosion behaviors of Si-Zr hybrid sol-gel coatings. The Si-Zr hybrid sol-gel coatings on a 2A12 aluminum substrate were prepared through hydrolysis and condensation of glycidoxypropyl-trimethoxy-silane (GTMS) and zirconium(IV) n-propoxide (TPOZ). Used as inhibitors for corrosion, three types of cerium salts (Ce(NO₃)₃, CeCl₃, and Ce(CH₃COO)₃) were doped into the sol-gel coatings. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were employed to investigate the structures and morphologies of various coatings, and the corrosion resistances of the coatings were evaluated by electrochemical methods and neutral salt spray tests. Experimental results indicate that the addition of cerium salts can hinder the process of corrosion due to their self-healing abilities. Furthermore, the sol-gel coating doped with Ce(CH₃COO)₃ has the best corrosion resistance because of the promotions of hydrolysis and condensation provided by CH₃COO^-.