Anticorrosive interfacial coatings for metallic substrates

The present state-of-the-art in anticorrosive coatings technology is a multistep process where multilayered hybrid coatings are applied on metallic substrates with each layer having certain functionality and properties. These layers are mainly an interfacial layer, such as inorganic phosphate coatings and/or sol-gel hybrid coatings, which are accompanied by a paint/polymer topcoat. While the main characteristic of the polymer topcoat is a "barrier" role to prevent the diffusion of corrosive species to the metal surface, the primer or the first layer in contact with metal surface is of significant importance due to its role in "active" corrosion prevention capability and promotion of strong adhesion between the substrate surface and subsequent layers. In this article, recent developments in processing and functional properties of zinc-phosphate sacrificial primers and sol-gel-based hybrid coatings will be overviewed. Finally, some of the innovative advancements in this area developed by this research group and others will also be discussed.