Super black is a surface treatment developed at the National Physical Laboratory (NPL) in the United Kingdom. It absorbs approximately 99.6% of visible light at normal incidence, while conventional

black Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white ...

paint absorbs about 97.5%. At other angles of incidence, super black is even more effective: at an angle of 45°, it absorbs 99.9% of light.

Technology

The technology to create super black involves chemically

etching Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal. In modern manufacturing, other chemicals may be used on other types ...

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...

. Applications of super black are in specialist

optical instruments An optical instrument (or "optic" for short) is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes ...

for reducing unwanted reflections. The disadvantage of this material is its low optical thickness, as it is a surface treatment. As a result, infrared light of a wavelength longer than a few micrometers penetrates through the dark layer and has much higher reflectivity. The reported spectral dependence increases from about 1% at 3 µm to 50% at 20 µm. In 2009, a competitor to the super black material,

Vantablack Vantablack is a brand name for a class of super-black coatings with total hemispherical reflectances (THR) below 1.5% in the visible spectrum. The coatings were invented by Ben Jensen, who first publicly unveiled them in July 2014, and commerci ...

, was developed based on

carbon nanotubes A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon na ...

. It has a relatively flat reflectance in a wide spectral range. In 2011, NASA and the US Army began funding research in the use of nanotube-based super black coatings in sensitive optics. Nanotube-based superblack arrays and coatings have recently become commercially available.

References

External links

* * * * {{cite web , url= http://www.acktar.com/category/VacuumBlack , title= Magic Black, Vacuum Black , publisher= Acktar , work= Advanced coatings , quote= Inorganic, thin coating, deposited using vacuum deposition technology Materials science Optical materials Shades of black

Technology

See also

References

External links