Atmospheric pressure pulsed arc plasma source and methods of coating therewith
An atmospheric pressure pulsed arc plasma source and method of using including a housing having a housing opening therein; an insulator tube having an insulator tube opening therein, retained within the housing opening; and a conductive tube, retained within the insulator tube opening. A nozzle is retained by the housing. A feed path is defined in the conductive tube and the nozzle and a gas feed port is operatively coupled to the feed path. Feedstock is provided in the feed path and electrically coupled to the conductive tube. A pulsed DC power source provides a pulsed voltage to the conductive tube. The plasma source emits a discharge stream having a temperature that is less than 50° C. from the nozzle and a coating is formed on a substrate.
1. A method of treating a surface, comprising:
providing an atmospheric pressure pulsed arc plasma source, including a housing, including at least two pieces and a housing opening therein; an insulator tube having an insulator tube opening therein, wherein said insulator tube is retained within said housing opening; a conductive tube retained within said insulator tube opening, wherein said conductive tube includes a first portion and a second portion; a nozzle retained by said housing pieces and positioned around the first portion of said conductive tube and said insulator tube; a feed path defined by said conductive tube and said nozzle; a gas feed port operatively coupled to said feed path; and a pulsed DC power supply electrically coupled to said conductive tube and said nozzle;
supplying a gas to said gas feed port from a gas supply;
feeding a consumable feed stock through said feed path, wherein said consumable feed stock provides an electrode and is electrically coupled to said conductive tube, and wherein said nozzle is formed of a material, wherein said material 1) is the same as said consumable feed stock or 2) comprises a metal or metal alloy;
supplying a pulsed voltage to said conductive tube from the pulsed DC power supply in the range of 0.5 to 100 kV relative to said nozzle at a pulse frequency in the range of 10 to 5000 Hz and a pulse width of 1 to 5000 μs;
forming a plasma with said gas in said nozzle;
emitting a discharge stream from said nozzle onto a substrate, wherein said discharge stream comprises said plasma and exhibits a temperature of less than 50° C. as measured by a thermocouple placed into said discharge stream 1 cm from the nozzle;
vaporizing said consumable feed stock and said material from said nozzle to form particles of said consumable feed stock and particles of said material from said nozzle, wherein said particles of said consumable feed stock and particles of said material are entrained in said discharge stream; and
depositing said particles onto said substrate to form a coating.
2. The method of claim 1 , wherein said gas is supplied at a pressure of 5 to 700 kPa.
3. The method of claim 1 , wherein said pulsed DC power supply supplies a current in the range of 1 to 1,000 A and power in the range of 1 to 1000 kW.
4. The method of claim 1 , wherein said gas is selected from Ar, N 2 , C 2 H 2 , air and combinations thereof.
5. The method of claim 1 , wherein said gas includes nitrogen and said consumable feed stock includes a metal, and said coating includes metal nitrides.
6. The method of claim 1 , wherein said gas includes carbon and said consumable feed stock includes a metal, and said coating includes metal carbides.
7. The method of claim 1 , wherein said gas includes carbon and nitrogen and said consumable feed stock includes a metal, and said coating include a metal carbo-nitride.
8. The method of claim 1 , wherein said gas includes argon and said consumable feed stock is a first material and said nozzle is a second material, and said first and second materials are the same.
9. The method of claim 1 , wherein said substrate is a polymeric material.
10. The method of claim 1 , wherein said consumable feed stock is electrically coupled to said conductive tube via a conductive wire.