In Situ PANI Encapsulation of Zinc Powder Enhancing the Corrosion Resistance of Zinc-Rich Epoxy Coatings

An approach to encapsulate zinc powder by in situ polymerization of aniline (PANI@Zn) is developed for Zn-rich epoxy coatings (ZRCs). With the application of PANI@Zn composites in the ZRCs, the encapsulated zinc particles are not activated due to the corrosion inhibition of PANI at the early stage of immersion, and physical shielding being mainly responsible for the protection of the steel substrate. At the stage of cathodic protection, the consumption of zinc powder is relatively uniform from the outer layer to the inner layer of the coating PANI@Zn coating, and the utilization rate of zinc powder is higher than that in the coating incorporated by the raw zinc powder. The required amount of zinc powder for achieving the same protective effect as the case of the raw zinc powder is reduced by ca . 20% after the application of the PANI@Zn composites.