PREPARATION OF AMORPHOUS BORON-NITRIDE FROM THE REACTION OF HALOBORAZINES WITH ALKALI-METALS AND FORMATION OF A NOVEL TUBULAR MORPHOLOGY BYTHERMAL ANNEALING

Amorphous boron nitride is obtained by a new, relatively low-temperatu re (120-210 degrees C) procedure that involves the reaction of B-triha loborazines, B(3)X(3)N(3)H(3) (X = Cl, Br) with alkali metals (Cs, Rb, K) in the absence of a solvent. The amorphous product after removal o f alkali metal halide and unreacted B(3)X(3)N(3)H(3) may be converted to the partially ordered turbostratic form of boron nitride by heating to 1100 degrees C. The material was characterized by IR spectroscopy, X-ray powder diffraction, and electron energy loss spectroscopy (EELS ). Detailed studies of the morphology of the product from the reaction of B,B',B''-trichloroborazine with cesium were carried out using scan ning electron microscopy and transmission electron microscopy. These r evealed a new, hollow tubular morphology for BN and also gave insight into possible reasons for its unexpected formation.