MACROSCOPIC SYNTHESIS OF ONION-LIKE GRAPHITIC PARTICLES

In this paper, we present a method for macroscopic synthesis of onion- like graphitic particles, which may be used to study physical properti es. This method is based on annealing carbon nanotubes under high pres sure. By transmission electron microscopy (TEM), the microstructure of carbon nanotubes is found to transform into quasi-spherical graphitic structures when the sample has been treated at 770 degrees C and 950 degrees C under 5.5 GPa. The high pressure assumes an important role i n this transformation. (C) 1998 Acta Metallurgica Inc.