Corrosion has a huge impact on metallic structures which not just affect the economy but also assets, environment and society. Finding measures to reduce and prevent corrosion damage is crucial. Organic coatings (epoxies), and inorganic coatings (polysiloxanes), have long been used to mitigate corrosion. Combining the best features of both organic and inorganic coatings to create high performance protective coatings is still a challenge.
Many studies have reported increased corrosion protection and durability through the use of these hybrid coatings which could be further enhanced with the incorporation of nanoparticles. Many nanoadditives are now commercially available and many more in the development stage, but integration into coatings is a key challenge since modifies its physical and mechanical properties.
The purpose within this investigation was to identify preliminary design rules by studying the effect and impact of these key materials in order to start establishing a materials by design approach which can be further developed and will help the integration of novel materials into industrial applications.
A sol-gel based coating was created to modify it with unfunctionalised and functionalised silica nanoparticles and study both their interaction with the coating matrix and their influence on coating morphology and mechanical durability. It was found that non-functionalised silica led to improved barrier properties, however, when the same silica was surface treated the corrosion resistance was further enhanced. Following that line of investigation, three
functionalisation levels as well as three loading levels of functionalised silica were examined. This study showed that the highest loading (20 wt.%) of the lowest functionalised silica (T0.1) led to coatings with improved properties and durability. This functionalised silica was homogeneously distributed within the polysiloxane-based matrix with no signs of agglomeration, highlighting the importance of the relation between nanoparticles, matrix and nanoparticle distribution as a key factor to improve coating performance.