Potentiality of UV-cured hybrid sol–gel coatings for aeronautical metallic substrate protection

The necessity of being compliant with the Health, Safety and Environment European rules and with the new assembly technologies is now more than ever an important driving force to replace existing aeronautical protection schemes. Hybrid sol–gels have been found to provide good corrosion resistance for metal substrates based on their ability to form dense barriers to the penetration of corrosion initiators (Raps et al., 2009; Wang and Bierwagen, 2009; Voevodin et al., 2003; Zheludkevich et al., 2005; Campazzi et al., 2007) [1], [2], [3], [4] and [5]. To decrease diffusion ways of corrosive species, some organic groups of organoalkoxysilanes can react via a light-induced process to form an organic network. Moreover, compared to conventional thermal curing, photopolymerization presents numerous advantages. Indeed, on the one hand the fast curing allows to decrease production cycles and consequently manufacturing costs. And on the other hand, the curing at room temperature with low energy consumption and without solvents presents clear eco-friendly benefits. In this context, the aim of our approach is to asses if the UV-curing can replace, or decrease, the conventional thermal curing to obtain hybrid sol–gel coatings able to protect aeronautical metallic substrates against corrosion.

► UV-cured hybrid sol–gel coatings could be obtained on metallic substrate.
► UV allows organic network's polymerization in addition of inorganic sol–gel network.
► The presence of photo-initiator negatively influences coating's adhesion properties.
► Curing process parameters control both O/I network's condensation degrees.
► Coating's performance could be improved by UV-process parameter's optimization.