Evolution of corrosion protection performance of hybrid silica based sol-gel nanocoatings by doping inorganic inhibitor

Silica based hybrid sol gel coatings were developed to protect AA2024 alloy from corrosion. In order to have an active protection, cerium nitrate corrosion inhibitor was introduced into the coating system. The anti-corrosion properties of the coatings were evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic scanning (PDS) methods. The structure of the films was studied by scanning electron microscopy (SEM) after corrosion. The results indicate that the improvement of the protection properties of the films occurred with immersion time. This would imply that cerium ions could reach the defects, hindering the corrosion reactions and thus reduces the corrosion rate.