A solid-state process for formation of boron nitride nanotubes

The formation of boron nitride (BN) nanotubes via a solid-state process is demonstrated. The nanotubes are produced by first ball-milling hexagonal BN powder to generate highly disordered or amorphous nanostructures, followed by annealing at temperatures up to 1300 degrees C. The annealing leads to the nucleation and growth of hexagonal BN nanotubes of both cylindrical and bamboo-like morphology. Unlike previous mechanisms for nanotube formation, the reordering and solid-state growth process of our nanotubes does not in volve deposition from the vapor phase nor chemical reactions. (C) 1999 Amer ican Institute of Physics. [S0003-6951(99)04320-X].