Currently known processes for carbon nanotube synthesis use either of the following methods: Arc, laser, solar, plasma or catalytic method. The first group, comprising the first four processes corresponds to the high temperature methods. Hereby, the NT formation process is based on the sublimation and recondensation of the carbon precursor. Within this group the first three processes having reached their limits in production rate. A fundamentally new approach is taken with the plasma process. Hereby, the carbon mass flow is no longer limited by a physical ablation rate, but is freely adjustable. Moreover, the process is operated at atmospheric pressure and the NT rich soot is extracted continuously. For ten years, an industrial consortium composed of Timcal Belgium, ENSMP and CNRS has developed a new process based on a 3-phase AC plasma technology for the continuous mass production of carbon nanostructures. This 3-phase AC plasma system; initially developed and optimised for the synthesis of novel grades of carbon black and later modified for the continuous synthesis of fullerenes, has been adapted for the synthesis of carbon nanotubes and tube-like structures. The feasibility for producing a large variety of different nanostructures at high selectivity including Carbon MWNTs, SWNTs, nanofibers and necklace nanostructures is well established. From the characteristics observed, it is concluded that the AC plasma technology shows a significant potential for the continuous production of bulk quantities of carbon-based nanotubes of controlled properties and novel nanostructures. In this paper, the plasma process for continuous nanotube synthesis and results on typical process conditions prevailing are presented.
Journal: TechConnect Briefs
Volume: 3, Technical Proceedings of the 2004 NSTI Nanotechnology Conference and Trade Show, Volume 3
Published: March 7, 2004
Pages: 228 - 231
Industry sector: Advanced Materials & Manufacturing
Topic: Carbon Nano Structures & Devices