The role of boron nitride in graphite plasma arcs

Novel graphitic nanostructures (e.g. nanotubes, graphitic onions, polyhedral particles, hemitoroidal nanotube caps and branched nanotubes) are produced by arcing graphite electrodes, containing hexagonal-BN, in inert atmospheres. The introduction of BN or B inside the graphite anode generates long (less than or equal to 20 mu m) and well graphitised carbon nanotubes exhibiting boron at their tips. High Resolution Electron Microscopy (HRTEM), Scaning Electron Microscopy (SEM), Electron Energy Loss Spectroscopy (EELS) and X-ray powder diffraction studies reveal the production of B4C crsytals, in addition to little amounts of BC3 nanotubes. Mass spectrometry (MS) studies over the generated soots indicate high yields of large fullerenes (e.g. C-70, C-76, and C-84) and thermo-Gravimetric analysis (TGA) of the nanostructures show high oxidation resistance.