Multi-walled carbon nanotubes were discovered to ignite if exposed to an intense flash of light such as from a household camera flash or laser. The product is composed of thin diameter multi-walled carbon nanotubes, amorphous carbon and some Fe nanoparticles/nanopowder. Optical ignition and initiation of energetic materials could this far be only accomplished through lasers, with specific characteristics of high power, pulse length, wavelength, and a small target area that greatly inhibit their applications. A comparison of the reactions when subjected to a camera flash and a laser found that a camera flash unit produced a slow, surface propagated deflagration while a laser produced a much faster explosion-like result which was determined to be preferable for controllable initiation of energetic materials.
The phenomenon is proposed as a novel initiation method for fuels or explosives. Such way of light initiation of materials provides many advantages over traditional initiation methods such as reduced degradation of the initiator over time, reduced interference from electrical fields, improved safety and faster ignition by initiating many points of a material at once. Multi-walled carbon nanotubes flash-ignition phenomenon has been used to trigger the combustion of different fuel typologies and is slowly replacing the method of traditional spark-plug ignition. The implication is that energetic materials mixed with optically active nanotubes could be new ideal candidates for safety apparatus, such as the firing of bolts on space shuttle rockets and aircraft exit doors.
The product is manufactured by xylene pyrolysis using ferrocene as catalyst. A mechanism for the flash ignition of a carbon nanotube occurs in three stages. At the first stage, when exposed to a flash, oxidation of an ultradispersed impurity of metals in the carbon nanotubes occurs. At the second stage, heating by chemical reactions occurs. The final stage is the initiation of the combustion wave.
Flash ignition of multi-walled carbon nanotubes applications:
Flash ignition of multi-walled carbon nanotubes is used in combustion and propulsion sectors.
Flash ignition of multi-walled carbon nanotubes is used in ignition agents for fuel mixtures.
Flash ignition of multi-walled carbon nanotubes is used in aerospace industry.
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