Intelligent Nanocoatings for Corrosion Protection of Steels

Date
2017
Journal Title
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Abstract
Intelligent coatings, also called smart coatings, refer to coating systems capable of sensing the generation of corrosive environments, and self-responding to corrosion occurrence in demand. In this research, an intelligent coating technology based on doping of home-prepared nanocontainers pre-loaded with inhibitors- in an epoxy host coating was developed for effective corrosion protection of pipeline steel. The performance of benzotriazole (BTA) inhibitors on preventing corrosion of an X65 pipeline steel was investigated in a bicarbonate solution. A layer of protective inhibitor film with a roughness of nano-meter scale was formed on the steel surface, inhibiting corrosion of the steel. To determine the compatibility of nanocontainers with the host coating, multi-layered Halloysite polyelectrolyte nanocontainers were fabricated and doped in an epoxy coating. The coating containing Halloysite nanocontainers possessed enhanced corrosion resistance. The corrosion resistance of the coating was improved with the increasing content of the Halloysite nanocontainers in the coating. To improve the ability of nanocontainers to encapsulate inhibitors BTA, a SiO2 nanoparticle based polyelectrolyte assembly was prepared as the BTA-encapsulating nanocontainers. At either low or high pH value (e.g., pH 2 or 11), the BTA was released to prevent steel from corrosion in chloride solutions. The Korsemeyer-Peppas model provided an estimation of the inhibitor-releasing rate, which served as the base for prediction of the service life of the intelligent coatings. An intelligent coating was developed by doping the BTA-encapsulated, SiO2 nano-particle-based polyelectrolyte nanocontainers in the epoxy coating. For the pipeline steel coated with the intelligent coatings, the corrosion inhibition was time dependent upon self-releasing of the encapsulated inhibitors from the nanocontainers. With the increasing content of the BTA-encapsulated nanocontainers in the coating, both the coating resistance and corrosion resistance of the steel increase, resulting in a reduced corrosion of the steel. Furthermore, superhydrophobic zinc nano-films were fabricated on X65 pipeline steel. The optimal condition for electrodeposition was under the current density of 100 mA/cm2 for 20 mins. The fabricated superhydrophobic, which had a water contact angle up to 158.4° ± 1.5°, possessed a satisfactory antifouling and self-cleaning ability, and provided an effective corrosion protection to the steel in a chloride solution.
Description
Keywords
Engineering--Chemical, Engineering--Environmental, Engineering--Industrial, Materials Science
Citation
Feng, Y. (2017). Intelligent Nanocoatings for Corrosion Protection of Steels (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26592