Method of producing nanoscale powders by quenching of vapors

Details Method of producing nanoscale powders by quenching of vapors Method of producing nanoscale powders by quenching of vapors

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.

REFERENCES:
patent: 4534917 (1985-08-01), Walz
patent: 4619845 (1986-10-01), Ayers et al.
patent: 5403375 (1995-04-01), Konig et al.
patent: 5407458 (1995-04-01), Konig et al.
Jacobson et al., "Rapid Solidification Processing," Mat. Sci. and Eng., R11, 335 (1994).
R. Uyeda, "Studies of Ultrafinie Particles in . . . ," Prog. Mater. Sci., 35, 1 (1991).
R. W. Siegel, Materials Science and Technology, 15, VCH, Weinhem, 583 (1991).
H. Jones, "Splat Cooling and Metastable Phases," Rep. Prog. Phys. 36, 1425 (1973).

Affiliated with

Also associated with

Rating

Method of producing nanoscale powders by quenching of vapors does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of producing nanoscale powders by quenching of vapors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing nanoscale powders by quenching of vapors will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1172759