Onion-like marbles and bats: new morphological forms of carbon

New spherical and bat-like carbon objects up to 1 mm in diameter and 3 mm i n length have been produced in a radio-frequency furnace by evaporation and deposition of pure carbon. The objects form without the use of any catalys t. They have been characterised by scanning and high-resolution transmissio n electron microscopy, energy-dispersive microanalysis, X-ray diffraction, Raman, infrared and electron energy loss spectroscopy, magnetic, thermograv imetric and micro-hardness measurements. The objects consist of nearly perf ect concentric shells, scaling down to nanometer dimensions in the centre. Their properties reveal similarities to both graphite and carbon nanotubes. (C) 2001 Elsevier Science B.V. All rights reserved.