Surface-modified mesoporous SiO2 containers for corrosion protection

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 design of a new protective system based on surface modified mesoporous silica containers. Incorporation of silica-based containers into special sol–gel matrix allows for a self-healing effect to be achieved during the corrosion process. The self-healing ability occurs due to release of entrapped corrosion inhibitors in response to pH changes caused by the corrosion process. A silica–zirconia-based hybrid film is used in this work as a coating matrix deposited on AA2024 aluminum alloy. Mesoporous silica nano-particles are covered layer-by-layer with polyelectrolyte layers and loaded with inhibitor [2-(benzothiazol-2-ylsulfanyl)-succinic acid]. The hybrid film with nanocontainers reveals enhanced long-term corrosion protection in comparison with the individual sol–gel films. The scanning vibrating electrode technique also shows an effective healing ability of containers to cure the corrosion defects. This effect is due to the 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.