Christopher Arnold Power

US Patent:

55736823, Nov 12, 1996

Filed:

Apr 20, 1995

Appl. No.:

8/426621

Inventors:

George P. Beason - Arab AL
Timothy N. McKechnie - Huntsville AL
Christopher A. Power - Guntersville AL

Assignee:

Plasma Processes - Huntsville AL

International Classification:

B23K 1000

US Classification:

2191215

Abstract:

An improved nozzle for reducing overspray in high temperature supersonic plasma spray devices comprises a body defining an internal passageway having an upstream end and a downstream end through which a selected plasma gas is directed. The nozzle passageway has a generally converging/diverging Laval shape with its upstream end converging to a throat section and its downstream end diverging from the throat section. The upstream end of the passageway is configured to accommodate a high current cathode for producing an electrical arc in the passageway to heat and ionize the gas flow to plasma form as it moves along the passageway. The downstream end of the nozzle is uniquely configured through the methodology of this invention to have a contoured bell-shape that diverges from the throat to the exit of the nozzle. Coating material in powder form is injected into the plasma flow in the region of the bell-shaped downstream end of the nozzle and the powder particles become entrained in the flow. The unique bell shape of the nozzle downstream end produces a plasma spray that is ideally expanded at the nozzle exit and thus virtually free of shock phenomena, and that is highly collimated so as to exhibit significantly reduced fanning and diffusion between the nozzle and the target.

US Patent:

52493571, Oct 5, 1993

Filed:

Jan 27, 1993

Appl. No.:

8/009908

Inventors:

Richard R. Holmes - Guntersville AL
Timothy N. McKechnie - Huntsville AL
Christopher A. Power - Guntersville AL
Ronald L. Daniel - Huntsville AL
Robert M. Saxelby - Santa Susana CA

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

B23P 1500

US Classification:

2989001

Abstract:

A process for making a combustion chamber for a rocket engine wherein a copper alloy in particle form is injected into a stream of heated carrier gas in plasma form which is then projected onto the inner surface of a hollow metal jacket having the configuration of a rocket engine combustion chamber. The particles are in the plasma stream for a sufficient length of time to heat the particles to a temperature such that the particles will flatten and adhere to previously deposited particles but will not spatter or vaporize. After a layer is formed, cooling channels are cut in the layer, than the channels are filled with a temporary filler and another layer of particles is deposited.