Safer, cleaner aluminium plating using ionic liquids
A successful industrial process for aluminium electroplating is a significant challenge in the surface finishing industry. Current solutions use hazardous solvents such as toluene or vapour deposition, which carry significant obstacles to safe deployment and scale-up. C-Tech has developed a fully-automated aluminium plating process using ionic liquids that represents a significant improvement on current methods.
Aluminium is a non-toxic metal that could be a cost-effective alternative for substituting conventional and harmful coatings like decorative chromium films. Aluminium-coated nickel alloys also have wide application in high-temperature corrosion-resistant aerospace components, particularly in replacing cadmium coatings.Aluminium is one of the most promising metals for new engineered metallic materials as it is a lightweight material with a density of 2.7 g/cm3 (0.1 lb/in.3), it has high mechanical strength achieved by suitable alloying and heat treatments, and it has a relatively high corrosion resistance as pure metal. Other valuable properties include its high thermal and electrical conductance, its reflectivity, its high ductility, its magnetic neutrality and the non-poisonous and colorless nature of its corrosion products.
As aluminium is extremely chemically reactive the aqueous processes used for plating other metals are not applicable. Conventional approaches to aluminium plating have included harmful raw processes involving as cyanide baths and hexavalent chromium salts, or energy-intensive options like pack cementation. While ionic liquids have been studied for years as a potential solution to hazardous plating methods, success has been limited to lab-scale experiments. C-Tech Innovation is the first company to scale ionic liquid aluminium plating as part of the SCAIL-UP project, demonstrating the industrial feasibility of this method of plating.
The resulting process is more energy and material efficient than existing alternatives, and is ready for deployment in an industrial setting. C-Tech Innovation’s SCAIL-UP equipment is fully automated, maintaining an anhydrous atmosphere (<10 ppm water) inside a sealed container with a series of plating baths and an internal crane for moving the target material between baths and the transfer chamber.