Cirrus Paint-free Colour™: Robust Coloured Coatings on (light metal) Alloys

C. Goode, F. Hou, I. Mardon
Cirrus Materials Science Ltd.,
New Zealand

Keywords: colour, VOC, nano, nanostructured, paint-free, light alloy


Cirrus Hybrid™ technology offers a means to deposit thin, corrosion resistant coatings on light metal alloys. Cirrus recently developed a novel evolution of this coating technology, Cirrus Paint-free Colour™, to directly deposit a range of coloured coatings on these same alloys without the necessity for dyes, paints, or other toxic materials. Cirrus Hybrid™ Colour is a patented novel coating technology that delivers greater energy efficiency, environmental friendliness, and protection while offering a weight advantage over organic or paint coatings. Light alloys such as aluminium are often the first choice of material for applications in architecture, automotive and aerospace, due to a high strength-to-weight ratio and corrosion resistant oxide layers. Typically, these industries use paint or organic coatings which are not only highly energy intensive, but also use toxic chemicals that are increasingly challenged by sustainability concerns. Cirrus Hybrid™ Colour leverages a combination of anodisation and electro-deposition to create a nano-pore structure that interferes with the wavelengths of light on aluminium. The result is a uniformly coloured surface that is exceptionally scratch and corrosion resistant – providing a paint-free solution to manufacturing. The colours are produced by manipulation of the novel structure of the anodising tube arrays during the process to create a combination of plasmonic absorption and surface interference, allowing for a wide colour selection. Cirrus Paint-free Colour™ coatings are between 3 and 15 microns thick and are highly corrosion resistant. Cirrus Paint-free Colour™ offers a disruptive new sustainable coating system for light metal alloys, well suited to 3D- printed components. Cirrus Paint-free Colour™ for aluminium is 75% thinner, lighter and 5x more energy efficient to apply than paint. The features of Cirrus Paint-free Colour™ are: • Tough: embedded, hard-wearing, thin-film composite coating that both etches into the alloy and develops a final protective layer. • Light-weight: unlike existing light metal paints or other coatings, the process is subtractive and is suitable for light-weighting of components; these typically weigh the same or slightly less post finishing. • Simple: Cirrus Paint-free™ Colour requires fewer process steps to colour-coat aluminium compared with comparable paint systems. The benefits of Cirrus Paint-free Colour™ are: • Cost savings due to reduced application time, reduced energy use to apply and lower material input costs. • Enhanced asset life with a highly durable finish. • Sustainability via a light-weight, environmentally friendly alternative to paint and other organic coatings. The paper will discuss the process, properties and applications of Cirrus Paint-free Colour™ including corrosion and scratch performance results.