Submicronic powders containing carbon, boron and nitrogen: their preparation by chemical vapour deposition and their characterization

Submicronic powders containing carbon, boron and nitrogen have been prepare d by thermal chemical vapour deposition. The precursors of carbon, boron an d nitrogen are acetylene, boron trichloride and ammonia, respectively. Hydr ogen is the carrier gas. The conditions of preparation of these powders are rather different from those of thin films containing the same elements, Us ing X-ray photoelectron spectroscopy and transmission electron microscopy, both chemical analysis and microtexture are studied. It is shown that ex-ac etylene carbon blacks with a concentric 'onion-like' texture, quasi stoichi ometric boron nitrides with a platelet texture, boron-carbon solid solution s with a low boron content (3-19 at.%) and boron carbonitride powders with either carbon or boron and nitrogen excesses have been prepared, (C) 1999 E lsevier Science Ltd. All rights reserved.