Novel eco-friendly coatings and process technology
Most solvents are volatile organic compounds (VOCs) that evaporate into the air, posing a threat to workers who inhale the vapour. In addition, they eventually create carbon dioxide (CO2), the major greenhouse gas (GHG) associated with global warming. Great interest has thus been focused on replacing detrimental organic solvents with environmentally friendly or green ionic liquids (ILs) that do not evaporate. European researchers supported by funding of the Iolisurf project sought to develop high quality protective metal coatings based on ILs for the aerospace and gas turbine industries as well as the technology to mass produce and apply them. General applications include those in which complex shaped parts must be protected against extreme conditions of high temperature and corrosion. In fact, aluminide and chromide diffusion coatings (providing a barrier against diffusion of oxygen and other substances into the material) are widely used for thermal barrier protection of gas turbine blades. Researchers conducted extensive quantitative structure activity relationship (QSAR) studies of innovative ILs to choose those most suitable for electro-deposition of aluminium, chromium and related alloys and thus provide an important alternative to standard technology. Iolisurf investigators successfully developed technology for previously unattainable electro-deposition of aluminium, overcoming a major obstacle in VOC-free electro-deposition. Post-treatment methods developed by the consortium improved properties permitting use in high temperature, high-corrosion environments. Researchers developed similar processes for silver and chromium, providing a potential improvement over conventional aqueous (water-based) techniques. Potential applications include decorative or black coatings in the solar or heat-exchanger markets as well as in targeted aerospace components and for gas turbine manufacturers. Thus, commercial exploitation of Iolisurf technologies could have important implications for a variety of manufacturing fields.
