Project Title:

Innovative Plasma Nozzle Techniques for Eliminating Overspray

92-1-04.24-7572                                                   NAS08-39802
Innovative Plasma Nozzle Techniques for
     Eliminating Overspray
Plasma Process
7802 Hilton Drive
Huntsville, AL  35802
George Philips Beason, Jr.                           (205-881-7572)

Abstract:

     Overspray and undeposited powder are serious problems for
vacuum and air plasma spray processes. Overspray and unmelted
powder increase the cost of the process through wasted material
and jeopardize the material quality of the deposits for both
coatings and structures. Overspray occurs because commercially
available plasma guns have poor nozzle design. Powder injected
into the plasma flame cannot enter the plasma, overshoots the
plasma, or, because of nozzle flow characteristics, is forced out
of the center of the flame. By designing and testing new models,
investigators can create plasma gun nozzles that have the desired
flow characteristics to entrain and melt the powder, thereby
eliminating, or severely reducing, overspray and undeposited
powder. The goal of this project will be to design and produce
perfectly expanded plasma-gun nozzles for optimizing plasma spray.

Potential Commercial Application:

Potential Commercial Applications:  Applications exist in many
fields, including aerospace (rocket genies, jet engines),
automotive (pistons, alternators, manifolds), and biomedical
(medical and dental implants). The nozzle could also be used in
superconductors, furnace retorts, and mills (rolling, paper).
Future applications include the spray of high cost materials such
as refractory metals, and precious metals.

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