Development of polyorganosilazane–silicone marine coatings

•Development of marine coatings based on crosslinked polyorganosilazanes (PSZ).•Paints are solvent-free and applied in one layer.•Silicone oil-based PSZ exhibit promising antifouling and anticorrosive properties. The objective of the present work is the development and characterization of marine coatings based on polyorganosilazanes (PSZ). Two types of coatings containing silicone oils and biocidal compounds were investigated as anticorrosive and antifouling coatings. The flexibility, hydrophobicity and adhesion properties of the PSZ-based coatings on aluminum substrates were studied. Static immersions in natural seawater were investigated to evaluate the antifouling performances of these coatings. The corrosion properties were studied by salt spray tests. Results demonstrated that coatings based on silicone oils appeared to be the most efficient coatings in terms of antifouling and anticorrosive properties. Ten-month antifouling efficiency was revealed for biocide-free polydimethylsiloxane-based PSZ coatings in natural seawater static immersion. The adjunction of dicopper oxide as biocidal pigments was shown to decrease the stability in cans of the corresponding paints and therefore decreasing the flexibility of coatings. In addition, this pigment affected badly the anticorrosive properties of the coatings together with a short antifouling efficiency time. Thus, the silicone oil-based PSZ displayed remarkable advantages in addition to their dual antifouling and anticorrosive properties which are the absence of biocidal compounds released in marine environment and the absence of volatile solvent.