Carbon nanotubes formed in graphite after mechanical grinding and thermal annealing

Multi-walled carbon nanotubes with cylindrical and bamboo-type structures are produced in a graphite sample after mechanical milling at ambient temperature and subsequent thermal annealing up to 1400 °C. The ball milling produces a precursor structure and the thermal annealing activates the nanotube growth. Different nanotubular structures indicate different formation mechanisms: multi-wall cylindrical carbon nanotubes are probably formed upon micropores and the bamboo tubes are produced because of the metal catalysts. A two-dimensional growth governed by surface diffusion is believed to be one important factor for the nanotube growth. A potential industrial production method is demonstrated with advantages of large production quantity and low cost. Received: 17 May 2002 / Accepted: 12 September 2002 / Published online: 4 December 2002 RID="*" ID="*"Corresponding author. Fax: +61-2/6125-8338, E-mail: ying.chen@anu.edu.au