Specialized metallurgical processes – compositions for use therei – Processes – Producing solid particulate free metal directly from liquid...
Patent
1996-09-03
1998-08-04
Wyszomierski, George
Specialized metallurgical processes, compositions for use therei
Processes
Producing solid particulate free metal directly from liquid...
164 46, 264 12, B22F 912
Patent
active
057887381
ABSTRACT:
A thermal reactor system that produces nanoscale powders by ultra-rapid thermal quench processing of high-temperature vapors through a boundary-layer converging-diverging nozzle. A gas suspension of precursor material is continuously fed to a thermal reaction chamber and vaporized under conditions that minimize superheating and favor nucleation of the resulting vapor. According to one aspect of the invention, the high temperature vapor is quenched using the principle of Joule-Thompson adiabatic expansion. Immediately after the initial nucleation stages, the vapor stream is passed through the nozzle and rapidly quenched through expansion at rates of at least 1,000.degree. C. per second, preferably greater than 1,000,000.degree. C. per second, to block the continued growth of the nucleated particles and produce a nanosize powder suspension of narrow particle-size distribution. According to another aspect of the invention, a gaseous boundary-layer stream is injected to form a blanket over the internal surface of the nozzle to prevent vapor condensation in the throat of the nozzle and its potential failure.
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Pirzada Shahid
Yadav Tapesh
Nanomaterials Research Corporation
Wyszomierski George
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