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A method of operation of a plasma torch. A cold high pressure carrier gas containing a powder material is injected into a cold main high pressure gas flow and then this combined flow is directed coaxially around a plasma exiting from an operating plasma generator and converging into the hot plasma e

A method of operation of a plasma torch. A cold high pressure carrier gas containing a powder material is injected into a cold main high pressure gas flow and then this combined flow is directed coaxially around a plasma exiting from an operating plasma generator and converging into the hot plasma effluent, mixing with the effluent to form a gas stream with a net temperature, based on the enthalpy of the plasma stream and the temperature and volume of the cold high pressure converging gas, such that the powdered material will not melt. The combined flow with entrained is directed through a supersonic nozzle accelerating the flow to supersonic velocites sufficient that the particles striking the workpiece achieve kinetic energy transformation into elastic deformation of the particles as they impact the workpiece forming a cohesive coating.

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1. A method for applying a coating of powder particles to an article, the coating being formed of a cohesive layering of the particles in solid state on the surface of the article, the method comprising:first mixing powder particles and a carrier gas with a main gas, wherein the main gas has a press

1. A method for applying a coating of powder particles to an article, the coating being formed of a cohesive layering of the particles in solid state on the surface of the article, the method comprising:first mixing powder particles and a carrier gas with a main gas, wherein the main gas has a pressure between about 200 psig and about 600 psig, and subsequently heating the mixture of gases and particles with a plasma flame to an elevated temperature, which is controlled to be below the thermal softening temperature of the particles; subsequently accelerating the heated mixture of gases and particles into a supersonic jet and directing the jet of gases and particles in a solid state against the article so that the particles are caused to adhere to the article and build the cohesive coating. 2. The method of claim 1, wherein the mixture is mixed with a plasma flame to heat the mixture to a temperature below the thermal softening temperature of the particles.3. The method of claim 1, wherein the carrier gas has a pressure between about 200 psig and about 600 psig.4. The method of claim 1, wherein the particles have a particle size in excess of 50 microns.5. The method of claim 1, wherein the particles are of a size range, which is less than about 150 microns.6. The method of claim 1, wherein the step of controlling the temperature of the mixture of gases and particles is performed by adjusting the enthalpy of the plasma flame.7. The method of claim 1, wherein the powder particles are of at least one first material selected from the group of a metal, alloy, mechanical mixture or a metal and an alloy, and a mixture of at least one of a polymer, a ceramic and a semiconductor with at least one of a metal, alloy and a mixture of a metal and an alloy.8. The method of claim 1, wherein the particles are accelerated to a velocity of from about 300 to about 1,200 meters/second.9. The method of claim 1, wherein the carrier gas and main gas are selected from the group consisting of air, nitrogen, helium or a mixture thereof.10. The method of claim 1, wherein the plasma gas is selected from the group consisting of argon, argon/hydrogen or nitrogen.11. A method of applying a coating to an article, the coating being formed of a cohesive layering of the powder particles in solid state on the surface of the article, the method comprising;first mixing the powder particles and a carrier gas, wherein the particles of powder have a particle size in excess of 50 microns and are of at least one first material selected from the group consisting of a metal, alloy, mechanical mixture of a metal and an alloy or a mixture of at least one of a polymer, a ceramic and a semiconductor with at least one of a metal, alloy and a mixture of a metal and an alloy, with a main gas, wherein the main gas has a pressure between about 200 psig and about 600 psig; and second, heating the mixture of gases and particles with a plasma flame to an elevated temperature, which temperature is controlled to be below the thermal softening temperature of the particles; and third, accelerating the mixture of elevated temperature gases and particles into a supersonic jet having a velocity of from about 300 to about 1,200 m/sec; and directing the supersonic jet of gas and particles in a solid state against an article of a second material selected from the group consisting of a metal, alloy, semiconductor, ceramic and plastic, and a mixture of any combination thereof, thereby coating the article with a desired thickness of particles. 12. The method of claim 11, wherein the caner gas pressure and the main gas pressure are between about 200 psig and about 600 psig.13. The method of claim 11, wherein the particles are of a size range of less than about 150 microns.14. The method of claim 11, wherein the plasma gas is selected from the group consisting of argon, argon/hydrogen or nitrogen.15. The method of claim 11, wherein the carrier gas and the main gas are selected from the group consisting of air, nitrogen or helium or a mixture thereof.16. A method of applying a coating to an article, the coating being formed of a cohesive layering of the powder particles in solid state on the surface of the article, the method comprising;first mixing the powder particles and a carrier gas, wherein the particles of powder are of a size range from about 1 micron to about 50 microns and are of at least one first material selected from the group consisting of a metal, alloy, mechanical mixture of a metal and an alloy or a mixture of at least one of a polymer, a ceramic and a semiconductor with at least one of a metal, alloy and a mixture of a metal and an alloy, with a main gas, wherein the main gas has a pressure between about 200 psig and about 600 psig; and second, heating the mixture of gases and particles with a plasma flame to an elevated temperature, which temperature is controlled o be below the thermal softening temperature of the particles; and third, accelerating the mixture of elevated temperature gases and particles into a supersonic jet having a velocity of from about 300 to about 1,200 m/sec; and directing the supersonic jet of gas and particles in a solid state against an article of a second material selected from the group consisting of a metal, alloy, semiconductor, ceramic and plastic, and a mixture of any combination thereof, thereby coating the article with a desired thickness of particles. 17. A method for applying a coating of powder particles to an article, the coating being formed of a cohesive layering of the particles in solid state on the surface of the article, the method comprising:first mixing powder particles and a carrier gas, wherein the carrier gas has a pressure between about 200 psig, to about 600 psig with a main gas, and subsequently heating the mixture of gases and particles with a plasma flame to an elevated temperature, which is controlled to be below the thermal softening temperature of the particles; subsequently accelerating the heated mixture of gases and particles into a supersonic jet and directing the jet of gases and particles in a solid state against the article so that the particles are caused to adhere to the article and build the cohesive coating. 18. The method of claim 17, wherein the mixture is mixed with a plasma flame to heat the mixture to a temperature below the thermal softening temperature of the particles.19. The method of claim 17, wherein the particles have a particle size in excess of 50 microns.20. The method of claim 17, wherein the particles arc of a size range, which is less than about 150 microns.21. The method of claim 17, wherein the step of controlling the temperature of the mixture of gases and particles is performed by adjusting the enthalpy of the plasma flame.22. The method of claim 17, wherein the powder particles are of at least one first material selected from the group of a metal, alloy, mechanical mixture of a metal and an alloy, and a mixture of at least one of a polymer, a ceramic and a semiconductor with at least one of a metal, alloy and a mixture of a metal and an alloy.23. The method of claim 17, wherein the particles are accelerated to a velocity of from about 300 to about 1,200 meters/second.24. The method of claim 17, wherein the carrier gas and main gas are selected from the group consisting of air, nitrogen, helium or a mixture thereof.25. The method of claim 17, wherein the plasma gas is selected from the group consisting of argon, argon/hydrogen or nitrogen.26. A method of applying a coating to an article, the coating being formed of a cohesive layering of the powder particles in solid state on the surface of the article, the method comprising;first mixing the powder particles and a carrier gas, wherein the carrier gas has a pressure between about 200 psig, to about 600 psig and wherein the particles of powder have a particle size in excess of 50 microns and are of at least one first material selected from the group consisting of a metal, alloy, mechanical mixture of a metal and an alloy or a mixture of at least one of a polymer, a ceramic, and a semiconductor with at least one of a metal, alloy and a mixture of a metal and an alloy, with a main gas; and second, heating the mixture of gases and particles with a plasma flame to an elevated temperature, which temperature is controlled to be below the thermal softening temperature of the particles; and third, accelerating the mixture of elevated temperature gases and particles into a supersonic jet having a velocity of from about 300 to about 1,200 m/sec; and directing the supersonic jet of gas and particles in a solid state against an article of a second material selected from the group consisting of a metal, alloy, semiconductor, ceramic and plastic, and a mixture of any combination thereof, thereby coating the article with a desired thickness of particles. 27. The method of claim 26, wherein the main gas pressure arc between about 200 psig and about 600 psig.28. The method of claim 26, wherein the particles are of a size range of less than about 150 microns.29. The method of claim 26, wherein the plasma gas is selected from the group consisting of argon, argon/hydrogen or nitrogen.30. The method of claim 26, wherein the carrier gas and the main gas are selected from the group consisting of air, nitrogen or helium or a mixture thereof.