Corrosion protection of AA2024-T3 by sol-gel film modified with graphene oxide

Graphene oxide (GO) was introduced into sol-gel systems to enhance the corrosion protective properties of the obtained film on AA2024-T3 aluminum alloy. The characterization of morphology, microstructure and component of the films indicated that GO covalently reacted with silanol groups from hydrolyzed 3-glycidoxypropyl-trimethoxysilane (GPTMS) monomer, forming silane functionalized GO (SGO) by C-O-Si covalent bonds. Corrosion protective properties of the films were evaluated through electro-chemical impedance spectroscopy (EIS), potentiodynamic polarization and immersion tests studies. The results showed that the addition of GO improved the corrosion protective properties of sol-gel film distinctly by providing the good barrier property of layered GO and enhancing the cross-linking density of the film. The significant improvement of GO on sol-gel film mainly focused on the resistance and capacitance of film itself. The optimal concentration of GO addition was 0.5 mg mL(-1), at which the film was uniform and showed good corrosion protective properties in 0.05 M NaCl aqueous solution. The corrosion current density of the sol-gel film with 0.5 mg mL(-1) GO was one order magnitude smaller than that of sol-gel film without GO. The protection efficiency of the film was up to 99.45%. (C) 2017 Elsevier B.V. All rights reserved.