Super black explained

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

External links

Notes and References

  1. Web site: Mini craters key to 'blackest ever black'. 6 February 2003. Newscientist.com. 2015-07-14.
  2. Web site: Highly Absorbing Surfaces for Radiometry. January 2003. https://web.archive.org/web/20050627082550/http://www.npl.co.uk/optical_radiation/superblack.html. 2005-06-27.
  3. 10.1039/b204483h. The physical and chemical properties of electroless nickel – phosphorus alloys and low reflectance nickel – phosphorus black surfaces. 2002. Brown. Richard J. C.. Brewer. Paul J.. Milton. Martin J. T.. Journal of Materials Chemistry. 12. 9. 2749.
  4. Web site: NASA Develops Super-Black Material That Absorbs Light Across Multiple Wavelength Bands . Nasa.gov . 2011-11-08 . 2015-07-14.
  5. https://sbir.gsfc.nasa.gov/content/nanostructured-super-black-optical-materials Nanostructured Super-Black Optical Materials
  6. Web site: Aligned Carbon Nanotube Arrays and Forests on Substrates . Nano-lab.com . 2015-07-14.