PREPARATION OF AMORPHOUS BORON-NITRIDE AND ITS CONVERSION TO A TURBOSTRATIC, TUBULAR FORM

Amorphous boron nitride, BN, is obtained from the reaction of B-trichloroborazine, (BClNH)3, with cesium metal. The amorphous product is converted to a turbostratic form upon heating to 1100-degrees-C. Scanning electron microscopy reveals a previously unreported morphology composed of hollow tubular structures. The largest of these appear to be approximately 3 micrometers in external diameter and 50 to 100 micrometers in length. Transmission electron microscopy and selected-area electron diffraction also indicate the tube walls to be turbostratic in nature. The mechanism by which the tubes form is not known, although apparent sites of incipient tube growth have been observed.