Preparation of Amorphous Boron Nitride from the Reaction of Haloborazines withAlkali Metals and Formation of a Novel Tubular Morphology by Thermal Annealing

摘要

Amorphous boron nitride is obtained by a new, relatively low-temperature (120-210deg C) procedure that involves the reaction of B-trihaloborazines, B3X3N3H3 (X = Cl, Br) with alkali metals (Cs, Rb, K) in the absence of a solvent. The amorphous product after removal of alkali metal halide and unreacted B3X3N3H3 may be converted to the partially ordered turbostratic form of boron nitride by heating to 1100 deg 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 scanning electron microscopy and transmission electron microscopy. These revealed a new, hollow tubular morphology for BN and also gave insight into possible reasons for its unexpected formation. jg p.1.