Self-Healing Corrosion Resistive Coatings Based on Inhibitor Loaded TiO₂Nanocontainers

Abstract

The present paper deals with the development of a self healing corrosion protection coating containing inhibitor loaded nanocontainers over modified 9Cr-1Mo steel, which is used as a structural and tubing material for various chemical and power plant applications. Basically, nanocontainers can release encapsulated corrosion inhibitors in a controlled manner and be used to develop a new group of rapid self-repairing coatings which possess passive functionality and active response to changes in the local environment. In the present investigation, TiO2 nanotube powder was synthesized by rapid breakdown anodization (RBA) and loaded with benzotriazole (BTA) inhibitor. The inhibitor loaded TiO2 nanotube powder was randomly introduced into a silane-titania passive barrier coating. This silane-titania based hybrid sol-gel coating with random distribution of such loaded TiO2 nanotube powder was coated over modified 9Cr-1Mo steel. The corrosion resistance and the self healing effects of the silane-titania hybrid passive barrier coatings, with and without the addition of inhibitor loaded TiO2 nanocontainers, were studied using electrochemical impedance spectroscopy (EIS). The silane-titania hybrid coating with inhibitor loaded nanocontainers performed better than other coatings obtained such as (i) the silane-titania hybrid coating, (ii) the silane-titania hybrid coating with inhibitor mixed directly and (iii) the silane-titania hybrid coating doped with nanocontainers.