METHOD AND APPARATUS FOR PRODUCING NANOSTRUCTURED CERAMIC POWDERS AND WHISKERS

摘要

A method and apparatus for forming non-agglomerated nano-structured ceramic powders from metalorganic precursors which combines rapid thermal decomposition of a precursor/carrier gas stream in a heated tubular reactor (17) with rapid condensation of the product particles on a rotating cold substrate (21) under a reduced inert gas pressure of 1-50 mbar. A mass flow controller (14) supplies carrier gas (13), and a valve (16) supplies the mixture of carrier gas and precursor (15). Vacuum pump (26) maintains the reduced pressure in reaction chamber (11). The product is removed from the substrate (21) by a scraper (23) and collected in compartment (25). The method is suitable for forming n-SiCxNy, n-ZrOxCy, metals, intermetallics, semiconductors, superconductors, ferro-electrics, optically active materials and magnetic materials. The n-SiCxNy compounds can be further reacted to form SiC or Si3N4 whiskers by heating in a hydrogen or ammonia atmosphere.