Anti-corrosion coating for metal surfaces based on superhydrophobic electrosprayed carbon layers

Abstract

The electrospray deposition of a carbon-polymer ink has been used for the preparation of corrosion protective coatings for metal substrates. The electrosprayed carbon layers are adherent and have highly porous structure that renders Cassie–Baxter type superhydrophobicity. The analysis of their morphology with SEM shows changes in the shape of aggregates with thickness that slightly affects their interaction with water and superhydrophobicity, as a consequence of changing electrospray deposition conditions. Stainless steel immersed in acidic aqueous solutions is efficiently protected from chemical and electrochemical corrosion when coated with electrosprayed carbon layers. The carbon layers with loads above 0.4 mg cm−2 are able to avoid water contact with the metallic surface, permanently and during electrochemical polarization, thanks to their internal superhydrophobicity. Electrosprayed carbon coatings convey cheap and durable protection against aqueous corrosive environments. This coating procedure is very appropriate for the protection of internal components in fuel cells (plates, contacts), electrolyzers, and batteries working with aqueous solutions, due to its superhydrophobicity and good electronic conductivity.