Self-Healing Corrosion Resistive Coatings Based on Inhibitor Loaded TiO₂Nanocontainers

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, TiO 2 nanotube powder was synthesized by rapid breakdown anodization (RBA) and loaded with benzotriazole (BTA) inhibitor. The inhibitor loaded TiO 2 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 TiO 2 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 TiO 2 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.