Corrosion is a major problem for durability of many metals and alloys. Among the efficient classical surface treatments, chromate-based treatments must be banished from industrial use due to their toxicity. At the same time, sol-gel routes have demonstrated high potential to develop an efficient barrier effect against aggressive environments. By this process, the anti-corrosion property can be also associated to others in the case of the development of multi-functional hybrid coatings. In this paper, the main goal is precisely to improve both the corrosion resistance and the adhesion properties of phosphated zinc substrates by the deposition of a hybrid (organic-inorganic) sol-gel layer. To reach this double objective, a choice between two formulations 3-glycidoxypropyltrimethoxysilane (GPTMS)/aluminum-tri-sec-butoxide (ASB) and 3-(trimethoxysilyl)propylmethacrylate (MAP)/tetraethylorthosilicate (TEOS) was firstly made based on the results obtained by microstructural characterizations using SEM, optical analysis, and mechanical characterization such as shock and/or scratch tests (coupled to climatic chamber and salt spray exposure). Several investigations were performed in this study, and the best formulation and performances of the system were obtained by adding a new precursor (1-[3-(trimethoxysilyl)propyl]ureido-UPS) under controlled conditions, as detailed in this paper.

Self-healing polymers are a new class of material that has recently received a lot of attention because of the lifespan improvement it could bring to multiple applications. One of the major challenges is to obtain multifunctional materials which can self-heal and exhibit other interesting properties such as protection against corrosion. In this paper, the effect of the incorporation of an aminosilane on the properties of a self-healing organic polymer containing disulfide bond is studied on films and coatings for aluminium AA2024-T3 using simple one step in situ synthesis. Hybrid coatings with enhanced anticorrosion properties measured by EIS were obtained thanks to the formation of a protective oxide interface layer, while exhibiting wound closure after exposition at 75 °C. The thermal, mechanical and rheological properties of the films with different aminosilane amounts were characterized in order to understand the influence of the slight presence of the inorganic network. Stiffer and reprocessable hybrid films were obtained, capable to recover their mechanical properties after healing. The nanocomposite structure, confirmed by TEM, had a positive effect on the self-healing and stress relaxation properties. These results highlight the potential of sol-gel chemistry to obtain efficient anticorrosion and self-healing coatings.

The aim of our study is to improve the aluminium alloy corrosion resistance with Organic-Inorganic Hybrid (OIH) sol-gel coating. Coatings are obtained from unusual formulation with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS), zirconium (IV) propoxide (TPOZ) and aluminium tri-sec-butoxide (ASB). This formulation was characterized and compared with sol formulations GPTMS/TPOZ and GPTMS/ASB. In each formulation, a corrosion inhibitor, cerium (III) nitrate hexahydrate, is employed to improve the corrosion performance. Coatings obtained from sol based on GPTMS/TPOZ/ASB have good anti-corrosion performances with Natural Salt Spray (NSS) resistance of 500 h for a thickness lower than 4 µm. Contact angle measurement showed a coating hydrophobic behaviour. To understand these performances, nuclear magnetic resonance (NMR) analyses were performed, results make sol-gel coating condensation evident and are in very good agreement with previous results.

This work was aimed at developing new coatings on biodegradable substrates for possible use in food packaging. In order to study barrier properties of these coatings made from fatty acid dispersions, oxygen permeability, water vapor permeability and also contact angle measurements were carried out. The coatings made from a fatty acid exhibited good barrier properties towards oxygen gas. Moreover, these coatings presented a higher contact angle value than the one obtained directly for the substrate without coating; this can be likely due to the hydrophobic nature of fatty acid and the recrystallization of fatty acid during the drying process.