Vantablack® is a thin film of carbon nanotubes (CNTs) directly 'grown' on the surface of a substrate (or object) in a reactor chamber. Surrey NanoSystems' unique process allows CNTs to be grown at much-lower temperatures than conventionally, enabling Vantablack's use on a very wide range of substrates. Vantablack has been successfully applied to a number of materials, including:
- aluminium sheet/foil, aluminium oxide, aluminium nitride
- aluminium alloys (6000, 7000 series)
- silicon, silicon dioxide
- stainless steel
- titanium, titanium nitride
The process used to grow Vantablack allows deposition on stable substrate materials with melting points above 450°C. (NB: the alternative spray-on version Vantablack S-VIS lowers this temperature requirement to 100°C.)
Vantablack is applied in a similar way to conventional thin-films. It can be applied directly to the product, including those with complex three-dimensional shape, or used to coat tiles or flexible foils for subsequent assembly into the final product.
The fine nanometre-sized optical cavities that make Vantablack so dark mean it cannot be used in environments open to direct contact and mechanical abrasion. It needs to be protected from accidental touching, for example behind or inside a component, or situated where contact is avoided.
Applying Vantablack S-VIS
Vantablack S-VIS is a sprayable version, so it can be applied under controlled conditions in air (enclosed & filtered spray booth). The coating is built up over a number of passes until the correct thickness has been achieved. The applied coating then passes through a number of chemical functionalisation steps to bind it together and change its density. These processes typically take place from 100°C to 300°. The spray coating can be successfully applied to most engineering materials that are thermally stable at these temperatures.