SYNTHESIS AND CHARACTERIZATION OF CARBIDE NANORODS

THE properties and potential applications of carbon nanotubes filled w ith other materials have aroused much speculation(1-5). Strategies for filling nanotubes include irt situ growth in an are reactor using met al/carbon composites(2,5) and the capillarity-driven filling of open n anotubes using liquid reagents(3,4). Here we report an alternative app roach to the synthesis of nanoscale structures based on nanotubes, in which the tubes are converted to carbide rods by reaction with volatil e oxide and/or halide species. In this way we have been able to prepar e solid carbide nanoscale rods of TiC, NbC, Fe3C, SiC and BCx in high yield with typical diameters of between 2 and 30 nm and lengths of up to 20 mu m. Preliminary studies show that these rods share the propert ies of the bulk materials (such as magnetism and superconductivity), s uggesting that they might allow the investigation of the effects of co nfinement and reduced dimensionality on such solid-state properties. T hese carbide nanorods might also find technological applications in na nostructured composite materials.