Self-healing pipeline epoxy coatings

摘要

In this work, benzotriazole (BTA) inhibitors were deposited on the surface of nano-SiO_2 particles, which served as the inhibitor carriers. Polyelectrolytes were then adsorbed on the particle surface by a layer-by-layer method to prepare the nanocontainers to store inhibitors. The inhibitor-loading nanocontainers were characterized by a number of techniques, including scanning electron microscopy, energy-dispersive X-ray spectrum, Fast Fourier Infrared spectrum and thermal gravimetric analysis. The corrosion resistance and the nano-container doped epoxy coatings was evaluated by electrochemical impedance spectroscopy. Results demonstrate that the SiO_2 nanoparticles based polyelectrolyte nanocontainers are successfully fabricated to store BTA. The nano-containers added in NaCI solution are able to inhibit the corrosion of the steel. The inhibiting performance is improved with immersion time. The inhibiting efficiency is over 66% after 24 h of testing. It is expected that the inhibiting performance further increases with the continuous release of BTA from the nano-containers with time. When the steel coated with the BTA loaded nano-containers is immersed in NaCI solution, the corrosion inhibition is time dependent upon the release of encapsulated inhibitors from the containers. The change of solution pH upon the coating damage and generation of corrosive environment may trigger the opening of the nano-containers for inhibitor releasing.