Nanocarbons formed in a hot isostatic pressure apparatus

Carbon tubes or fibres with diameters ranging from 0.05 to 1 mu m have been produced in a hot isostatic pressure apparatus, using gas pressures up to 100 MPa. Nitrogen, argon or mixtures thereof have been used. Other carbon s tructures were also present in small amounts. Transmission electron microsc opy revealed tubes of cylindrical and conical shape. The semi-apex angles f or the conical tubes were measured to be close to 5, 10 and 20 degrees. A p ossible growth mechanism for the tubes of conical shape is proposed. (C) 19 99 Elsevier Science S.A. All rights reserved.