Research Abstract |
A twin roller system rapidly to quench chemicalspecies evaporated and excited in a thermal plasma was developed, by which the preparation of ultra fine powders of diamond and B-C-N nanotubes were successfully prepared. Both materials obtained were characterized with a TEM and by X-ray diffraction and EELS in detail. As a result, (1)The preparation and characterization of ultra fine diamond powders. Structural features in the diamond powders with average particle size of 80nm were clarified. From the structural features, the formation mechanism of the diamond powders was discussed from a view points of super-saturation. (2)Concurrent growth of BN-, C-, and B-C-N-nanotubes by a plasma evaporation method. Nanotuves were prepared from sintered B-C-N system and porous BC_xN by an evaporation method in a dc arc plasma. Carbon-, BN-nanotubes, and composite nanotubes of carbon with BN were successfully prepared, however, no BC_xN nanotubes with homogeneous composition were obtained. The reasons for this were discussed on the basis of the differences in vapor pressures between carbon and boron nitride. Also, a possible mechanism of the nanotube formation was described.
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