Anticorrosion Coatings with Self-Healing Effect Based on Nanocontainers Impregnated with Corrosion Inhibitor

TLDR

Active corrosion protection systems for metallic substrates are critically important for many industrial applications. This study develops a self‑healing protective system based on hybrid sol‑gel films doped with nanocontainers that release entrapped corrosion inhibitor in response to pH changes induced by corrosion. The system uses a silica‑zirconia hybrid film deposited on 2024 aluminum alloy, incorporating silica nanoparticles coated layer‑by‑layer with polyelectrolyte and benzotriazole layers that act as nanocontainers for the inhibitor. The nanocontainer‑doped film delivers enhanced long‑term corrosion protection and effective self‑healing, as confirmed by scanning vibrating electrode technique, owing to regulated inhibitor release triggered by corrosion, and is suitable for broad applications.

Abstract

The development of active corrosion protection systems for metallic substrates is an issue of prime importance for many industrial applications. The present work shows a new contribution to the development of a new protective system with self-healing ability composed of hybrid sol−gel films doped with nanocontainers that release entrapped corrosion inhibitor in response to pH changes caused by corrosion process. A silica−zirconia based hybrid film was used in this work as an anticorrosion coating deposited on 2024 aluminum alloy. Silica nanoparticles covered layer-by-layer with polyelectrolyte layers and layers of inhibitor (benzotriazole) were randomly introduced into the hybrid films. The hybrid film with the nanocontainers reveals enhanced long-term corrosion protection in comparison with the undoped hybrid film. The scanning vibrating electrode technique also shows an effective self-healing ability of the defects. This effect is obtained due to regulated release of the corrosion inhibitor triggered by the corrosion processes started in the cavities. The approach described herein can be used in many applications where active corrosion protection of materials is required.