ROLE OF Y-NI-B MIXTURES IN THE FORMATION OF CARBON NANOTUBES AND ENCAPSULATION INTO CARBON CLUSTERS

We report on the formation of carbon nanotubes and encapsulated metal nanoparticles produced during the electric are discharge between a gra phite cathode and a graphitic anode containing different stoichiometri c mixtures of Ni, Y and B. Using these mixtures it can be shown that N i plays a catalytic role in the formation of single-walled nanotubes ( SWTs). However, the active catalytic amount of Ni used in the experime nt can be increased by additionally introducing certain other metals i n the anode. Their melting point, vapour pressure and their affinity t owards carbon seem to have an important influence on the amount of SWT s produced, as well as on the amount of metal particles encapsulated i n multi-walled nanotubes (MWTs) and graphitic polyhedral nanoparticles (GNPs).