Methods and apparatus for spray forming, atomization and heat transfer

Abstract

The present invention is directed to methods and apparatus that use electrostatic and/or electromagnetic fields to enhance the process of spray forming preforms or powders. The present invention also describes methods and apparatus for atomization and heat transfer with non-equilibrium plasmas. The present invention is also directed to articles, particularly for use in gas turbine engines, produced by the methods of the invention.

1 . A method for atomizing a particle comprising:
 producing a first molten particle;   applying a rapid electrostatic charge to the first molten particle, wherein the rapid electrostatic charge causes the first molten particle to form at least one smaller second molten particle; and   cooling the second molten particle by producing a non-equilibrium plasma that transfers heat from the second molten particle to a first heat sink, wherein the first heat sink is electrically charged or held at a potential.   
     
     
         2 . The method of  claim 1 , wherein the first molten particle is produced by melting a material in a melt chamber, and expelling the first molten particle through at least one orifice in the melt chamber. 
     
     
         3 . The method of  claim 1 , wherein the rapid electrostatic charge is an arc discharge or an electron beam. 
     
     
         4 . The method of  claim 1 , wherein the non-equilibrium plasma is a glow discharge or a cold corona discharge. 
     
     
         5 . An apparatus for transferring heat between a first heat transfer device and a workpiece comprising:
 the first heat transfer device, where the first heat transfer device is electrically charged or held at a potential, and wherein the first heat transfer device comprises a heat sink or a heat source;   the workpiece, wherein the workpiece is mechanically separate from the first heat transfer device; and   a means for transferring heat between workpiece and the first heat transfer device comprising a means for generating a non-equilibrium plasma.   
     
     
         6 . The apparatus of  claim 5 , wherein the non-equilibrium plasma is a glow discharge or a cold corona discharge. 
     
     
         7 . The apparatus of  claim 5 , further comprising an external means for generating or maintaining the non-equilibrium plasma. 
     
     
         8 . The apparatus of  claim 7 , wherein the external means for generating or maintaining the non-equilibrium plasma is a thermionic emission, an RF electromagnetic radiation, an electromagnetic radiation, a magnetic field or an electron beam. 
     
     
         9 . The apparatus of  claim 5 , wherein the first heat transfer device comprises a plurality of heat-transfer devices. 
     
     
         10 . The apparatus of  claim 5 , further comprising a second heat-transfer device that is mechanically and electrically separate from the first heat-transfer device, wherein the second heat-transfer device comprises a heat sink or a heat source, and wherein the potential between the first heat-transfer device and the second heat-transfer device produces a non-equilibrium plasma. 
     
     
         11 . A method for transferring heat between a first heat-transfer device and a workpiece comprising producing a non-equilibrium plasma that transfers heat between the first heat-transfer device and the workpiece, wherein the first heat-transfer device is electrically charged or held at a potential, wherein the first heat-transfer device is mechanically separate from the workpiece, and wherein the first heat-transfer device comprises a heat sink or a heat source. 
     
     
         12 . The method of  claim 11 , wherein the non-equilibrium plasma comprises a glow discharge or a cold corona discharge. 
     
     
         13 . The method of  claim 11 , further comprising an external means for producing or maintaining the non-equilibrium plasma. 
     
     
         14 . The method of  claim 11 , wherein the external means for producing or maintaining the non-equilibrium plasma comprises a thermionic emission, an RF electromagnetic radiation, an electromagnetic radiation, a magnetic field or an electron beam. 
     
     
         15 . A preform produced by the method of one of  claims 11 - 14 . 
     
     
         16 . The preform of  claim 15  which is a near net preform. 
     
     
         17 . An article of manufacture produced by the method of one of  claims 11 - 14 . 
     
     
         18 . The article of  claim 17  which is a component of a gas turbine engine.