Plasma Spray Method

Abstract

The invention relates to a plasma spray method which can serve as a starting point for a manufacture of metal nanopowder, nitride nanopowder or carbide nanopowder or metal films, nitride films or carbide films. To achieve an inexpensive manufacture of the nanopowder or of the film, in the plasma spray in accordance with the invention a starting material (P) which contains a metal or silicon oxide is introduced into a plasma jet ( 113 ) at a process pressure of at most 1000 Pa, in particular at most 400 Pa. The starting material (P) contains a metal or silicon oxide which vaporizes in the plasma jet ( 113 ) and is reduced in so doing. After the reduction, the metal or silicon which formed the metal or silicon oxide in the starting material is thus present in pure form or in almost pure form. The metal or silicon can be deposited in the form of nanopowder or of a film ( 124 ). Nitride nanoparticles or films or carbide nanoparticles or films can be generated inexpensively by addition of a reactant (R) containing nitrogen or carbon.

1 . A plasma spray method,
 in which a starting material is introduced into a plasma jet generated by a plasma generator at a process pressure in a process chamber of at most 1000 Pa,   wherein the starting material contains a metal or silicon oxide which is vaporized in the plasma jet and is therefore reduced in so doing.   
     
     
         2 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the starting material is composed only of metal oxide of a single metal.   
     
     
         3 . A plasma spray method in accordance with  claim 2 ,
 characterized in that   the starting material is introduced into the plasma jet as a powder.   
     
     
         4 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the metal oxide is zirconia, hafnium oxide or titanium oxide.   
     
     
         5 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the process pressure amounts to at most 400 Pa.   
     
     
         6 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   a supply rate of the starting material lies in a range between 0.5 and up to 5 g/min.   
     
     
         7 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   metal or silicon arising in the reduction of the metal or silicon oxide is deposited from the plasma jet.   
     
     
         8 . A plasma spray method in accordance with  claim 7 ,
 characterized in that   the metal or silicon is deposited in form of particles at a spacing between 100 and 400 mm remote from an exit nozzle for the plasma jet.   
     
     
         9 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   an additional reactant is introduced into the plasma jet and a reaction can thus take place between the reduced metal oxide and the reactant to form a reaction product.   
     
     
         10 . A plasma spray method in accordance with  claim 9 ,
 characterized in that   the reactant contains nitrogen and/or carbon.   
     
     
         11 . A plasma spray method in accordance with  claim 9 ,
 characterized in that   particles of the reaction product are deposited from the plasma jet.   
     
     
         12 . A plasma spray method in accordance with  claim 11 ,
 characterized in that   the particles of the reaction product are deposited at a spacing between 500 and 2000 mm remote from an exit nozzle for the plasma jet.   
     
     
         13 . A plasma spray method in accordance with  claim 7 ,
 characterized in that   the metal particles or the particles of the reaction product are deposited in the form of a powder.   
     
     
         14 . A plasma spray method in accordance with  claim 7 ,
 characterized in that   the metal particles or the particles of the reaction product are deposited in the form of a film on a substrate.