Boron nitride nanotubes, webs, and coexisting amorphous phase formed by the plasma jet method

Boron nitride (BN) nanotubes were prepared by a high-temperature plasma jet method. While the BN nanotubes were found in quantity on the surface of a BN sintered disk, amorphous BN webs were found dominant in the water-cooled collector. These structures were studied on the basis of transmission electron microscopy observations. One of them was composed of 21 layers grown coaxially with a regular spacing of 0.34 nm and their tip ends were terminated with parallel bases of the coaxial cylindrical shapes. The diameter of the innermost tube was 0.6 nm and this dimension is in fairly good agreement with the diameters of the smallest BN fullerenes. (C) 1999 American Institute of Physics. [S0003-6951(99)01833-1].