UK engineers have developed a light-weight material that absorbs 99.96% of surface light, believed to be the highest absorption recorded.
Launched at the Farnborough International Air Show, Surrey Nanosystems' Vantablack has been developed principally for use in critical air and space instrumentation. Ben Jensen, Chief Technology Officer at Nanosystems says: “it reduces stray-light, improving the ability of sensitive telescopes to see the faintest stars, and allows the use of smaller, lighter sources in space-borne black body calibration systems. Its ultra-low reflectance improves the sensitivity of terrestrial, space and air-borne instrumentation.”
Aside from its ultra-high light absorption, the major breakthrough is in creating a 'super black' material that uses a low temperature manufacturing process. Previous attempts have relied on high temperatures, making the materials unsuitable for direct application to sensitive electronics or materials with relatively low melting points. By contrast, Vantablack is made using a low-temperature carbon nanotube growth process usually used with silicon, where a solid material is desposited on a substrate from gas using photothermal chemical vapour deposition.
Crucially this means that Vantablack can be used for air and particularly space instrumentation, as it can be applied to more lightweight, temperature sensitive materials – specifically, aluminium. Jensen says: “It meant essentially transferring our technology that we'd developed for growth on silicon at low temperatures to aluminium flight qualified type materials, such as 6061 type substrates.”
The company claim the material has the highest thermal conductivity and lowest mass-volume of any material that can be used in high-emissivity applications. Of course, all would be for nought if it couldn't withstand launch, staging and longer term stresses. Fortunately, Vantablack passes all tests with flying colours in these areas. Jensen even claims it performed significantly better than anything that had been used before.
Terrestrial applications are also being investigated, where it will be useful for anything that requires excellent light suppression. Interestingly, Jensen says the material is highly tunable across a range of wavelengths, so if a particular frequency range – mid infra-reds, for example – needs particular attention Vantablack can be tuned to provide its best performance in that range.
Vantablack has been accredited by the European Cooperation on Space Standardisation (ECSS) and can be applied to flat and three-dimensional structures in precise patterns at sub-micron resolution. Due to its ultra-low reflectance, three-dimensional surfaces coated with Vantablack look flat. Speaking to Gizmag, Jensen said: “When you look at a surface it will just look very black. When you look at a 3D surface, you can't see any 3D shape. It just looks black.”
The material was created in partnership with the National Physical Laboratory and the ABSL Space Products division of Enersys as part of the UK Technology Strategy Board's Space for Growth programme and is commercially available now.
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