Hybrid sol-gel coating incorporated with TiO2 nanosheets and anti-corrosive effects on AA2024-T3

Abstract

Purpose This paper aims to improve the anti-corrosive properties of aluminum alloy AA2024-T3 by coating of hybrid sol-gel coating incorporated with TiO2 nanosheets and to investigate the effect of nanosheets’ size on the improvement of corrosion-resistant performance. Design/methodology/approach A series of hybrid sol-gel films incorporated with varying amounts of TiO2 nanosheets were developed to enhance the corrosion protection performance of the bare metal. Scanning electron microscopy, transmission electron microscopy and atomic force microscopy were used to investigate the structure and morphology of the coatings obtained. In addition, the corrosion-resistant properties of the coatings were evaluated using salt spray test and electrochemical impedance spectroscopy. Findings The corrosion current was as low as 9.55 × 10-4 µA/cm2 and optimal positive corrosion potential reached −0.6 V when the size and loading amount of TiO2 nanosheet were optimized, resulting in a remarkable improvement in anti-corrosive properties. Originality/value This work first investigates the effect of incorporation of TiO2 nanoparticles on hybrid sol-gel coating on the improvement of anti-corrosive performance of aluminum alloy AA2024-T3.