2-Mercaptobenzothiazole-Loaded Hollow Mesoporous Silica-Based Hybrid Coatings for Corrosion Protection of Modified 9Cr-1Mo Ferritic Steel

The present work describes the development of an active corrosion protection system consisting of organic-inorganic hybrid sol-gel coating impregnated with inhibitor-loaded nanocontainers. Hollow mesoporous silica spheres were synthesized using the sol-hydrothermal method and were then used as nanocontainers to load the corrosion inhibitor molecule, 2-mercaptobenzothiazole. A silane-zirconia-based hybrid coating containing hollow mesoporous silica nanocontainers were applied on modified 9Cr-1Mo ferritic steels. The loading and releasing properties of hollow mesoporous silica nanocontainers were studied using UV-visible spectroscopy. The corrosion resistance and active corrosion protection efficiency of hybrid silane-zirconia coatings with and without the addition of inhibitor-loaded hollow mesoporous silica (SiO2) nanocontainers were studied using electrochemical impedance spectroscopy and scanning electron microscopy. The anticorrosive property of the hybrid coating impregnated with inhibitor-loaded nanocontainers was found enhanced in comparison with both the hybrid coating and hybrid coating mixed with empty nanocontainers. This enhancement in corrosion resistance was due to controlled and sustained release of the corrosion inhibitor from nanocontainers embedded in the hybrid coating.