CARBON NANOTUBES FILLED WITH GADOLINIUM AND HAFNIUM CARBIDES

High-resolution transmission electron microscopy (HREM) has been used to examine the effect of metals on the ordering of carbon during fullerene generation by the the DC electric are discharge of metal-composite graphite rods. Investigations of the carbonaceous deposits formed on the top edge of the negative electrode confirmed the existence of graphitic polyhedra and carbon nanotubes filled with hafnium (Hf) carbide and gadolinium (Gd) carbide crystals. X-ray diffraction measurements indicate that the metals are incorporated in the form of HfC and GdC2. Possible mechanisms leading to the different stuctures formed in the presence of Hf and Gd are discussed. The continuous supply of sufficient numbers of metal atoms into the are plasma and moderate suppression of diffusion of the are plasma flow by increased He pressure was found to enhance the growth of the carbon nanotubes filled with metal carbides.