PROGRAM ON PLASMA-BASED ULTRAFINE PARTICLE SYNTHESIS
PROGRESS SUMMARY
An experimental system consisting of a thermal spray torch, a variable rate liquid delivery system, a liquid atomizer/feeder which can atomize a liquid jet and inject the droplets into the high pressure spray jet, an electrostatic precipitator and a substrate movement and control system has been built.
Nanomaterial powders and deposits have been produced using four different thermal spray techniques, viz., atmospheric plasma spray, electromagnetically coalesced (Flame Spray Industries, NY) plasma spray, combustion flame spray and high velocity oxy-fuel (Miller Thermal Inc., WI) spray.
A systematic experimental program is being carried out on the characterization of the atomizer and the spray jet, and on the preparation and characterization of nanoparticles and deposits. Raleigh backscattering, Laser Diffraction Analyzer (LDA), Laser Doppler Velocimetry (LDV), Laser strobe and Schlieren techniques are used for the process characterization. Optical microscopy, SEM, TEM and XRD are used for characterization of the spray synthesized nanomaterials.
Nanostructured alumina, zirconia, yttria stabilized zirconia and manganese oxide powders and deposits have been spray produced. Ceramic particles of 1-150 nm size were collected at a rate of ~ 5-20 mg/min., with ~ 20-35 % collection efficiency. Strong and adherent deposits with nanometers sized grains were obtained by heat treating the as-sprayed deposits.
last updated 03/05/96 by Dr. J. Karthikeyan
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