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Carbon nanotubes
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Synthesis
Synthesis
The phenomenon of carbon nanotube growth is not fully understood. However, observations from experiments point to the following growth diagram:
The carbon derived from a gas source, e.g. ethylene, breaks down in contact with iron. Following carbon saturation of the iron support particles, the carbon graphitizes into a tubular shape on the surface of the particle, and forms multilayer NTCs.
The reaction stops when the nanotube layer is such that the ethylene can no longer come into contact with the iron.
The detailed synthesis process for carbon nanotubes is confidential. Opposite is a simplified diagram of the main stages of the process:
1. Ethylene constitutes the source of carbon needed for the growth of nanotubes. The catalyst constitutes the source of iron.
2. The synthesis of nanotubes takes place at high temperature, on a fluidized bed.
3. The NTC powder is recovered and formulated to acquire optimum dispersive properties.
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