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
- ↑ "Mini craters key to 'blackest ever black'". Newscientist.com. 6 February 2003. https://www.newscientist.com/article/dn3356-mini-craters-key-to-blackest-ever-black.html.
- ↑ "Highly Absorbing Surfaces for Radiometry". January 2003. http://www.npl.co.uk/optical_radiation/superblack.html.
- ↑ 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.
- ↑ "NASA Develops Super-Black Material That Absorbs Light Across Multiple Wavelength Bands". Nasa.gov. 2011-11-08. http://www.nasa.gov/topics/technology/features/super-black-material.html.
- ↑ Nanostructured Super-Black Optical Materials 10/23/2013
- ↑ "Aligned Carbon Nanotube Arrays and Forests on Substrates". Nano-lab.com. http://www.nano-lab.com/alignedcarbonnanotubearrays.html.
External links
- Beckhusen, Robert (December 24, 2012). "Army Goes Goth with "'Super-Black' Materials". Wired. https://www.wired.com/dangerroom/2012/12/army-goth/.
- Quick, Darren (Nov 9, 2011). "NASA's new super-black nanotube-based material is good news for star-gazers". New Atlas. http://newatlas.com/super-black-material/20434/.
- "Super Black Coatings on a Mission". Paint Square. August 19, 2014. http://www.paintsquare.com/news/?fuseaction=view&id=11855. "Part of NASA's Materials Coating Experiment"
- "Magic Black, Vacuum Black". Advanced coatings. Acktar. http://www.acktar.com/category/VacuumBlack. "Inorganic, thin coating, deposited using vacuum deposition technology"
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