| 摘要 |
<p>A continuous process that produces nanoscale powders from different types of precursor material by evaporating the material and quenching the vaporized phase preferably in a converging diverging expansion nozzle. The precursor material suspended in a carrier gas is continuously vaporized at very high temperatures, preferably exceeding 2000 degrees C, and most preferably exceeding 5000 degrees K, in a thermal reaction chamber under conditions that favor nucleation of the resulting vapor. Immediately after the initial nucleation stages, the vapor stream is rapidly and uniformly quenched at rates of at least 1,000 K/sec, preferably above 1,000,000 K/sec, to block the continued growth of the nucleated particles and produce a nanosize powder suspension of narrow particle size distribution. The nanopowder is then harvested by filtration from the quenched vapor stream and the carrier medium is purified, compressed and recycled for mixing with new precursor material in the feed stream.</p> |
