PREPARATION AND PROPERTIES OF A COMPOUND IN THE B-C-N SYSTEM

Boron-carbon-nitrogen powders were prepared by a chemical process based on simultaneous nitridation of boric acid and carbonization of saccharose in molten urea. From the chemical analysis and infrared spectroscopy of the products obtained by changing the ratio of the three starting materials to control the BN/C ratio, the balance composition, which was obtained with neither free carbon nor boron nitride coexistent, was found to correspond to the formula BC4N. The powder had a turbostratic structure related rather to graphite than to boron nitride, based on its graphitization behavior. A sandwich structure model in which single boron nitride monolayers are inserted between pairs of carbon layers is proposed to interpret these facts and the infrared spectra, sharp contrast with a CVD product, which is considered as having B-N and C-C copolymer layer. (C) 1995 Academic Press, Inc.