Super black

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 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 a nickel-phosphorus alloy.[1][2]

Applications of super black are in specialist optical instruments 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.[3]

In 2009, a competitor to the super black material, Vantablack, was developed based on carbon nanotubes. It has a relatively flat reflectance in a wide spectral range.[4]

In 2011, NASA and the US Army began funding research in the use of nanotube-based super black coatings in sensitive optics.[5] Nanotube-based superblack arrays and coatings have recently become commercially available.[6]

See also

References
  1. "Mini craters key to 'blackest ever black'". Newscientist.com. 6 February 2003. Retrieved 2015-07-14.
  2. "Highly Absorbing Surfaces for Radiometry". January 2003. Archived from the original on 2005-06-27.
  3. Brown, Richard J. C.; Brewer, Paul J.; Milton, Martin J. T. (2002). "The physical and chemical properties of electroless nickel – phosphorus alloys and low reflectance nickel – phosphorus black surfaces". Journal of Materials Chemistry. 12 (9): 2749. doi:10.1039/b204483h.
  4. "NASA Develops Super-Black Material That Absorbs Light Across Multiple Wavelength Bands". Nasa.gov. 2011-11-08. Retrieved 2015-07-14.
  5. Nanostructured Super-Black Optical Materials 10/23/2013 Archived March 2, 2014, at the Wayback Machine
  6. "Aligned Carbon Nanotube Arrays and Forests on Substrates". Nano-lab.com. Retrieved 2015-07-14.
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