Controlled thermal coating

Abstract

The combined measurement of the particle velocity, temperature, intensity, and burner voltage and control thereof in a tolerance range makes it possible to keep the layer structure, the layer thickness and the layer weight constant in spite of wear-induced variations in the coating process.

1 . A method for thermal coating by means of a material flow ( 42 ) by means of a nozzle ( 30 ),
 in particular by means of a powder flow,   in which a material (M xy ) of the material flow ( 42 ) is heated, partially melted and/or melted,   in particular by means of a plasma or a flame,   in which at least one of the target variables (Z 1 , Z 2 , Z 3 , . . . )   material flow velocity (v p ) of the material flow ( 42 )   and/or   temperature (T) of the material flow ( 42 )   and/or   voltage (U B ) between an electrode ( 36 ) and the nozzle ( 30 ) are measured or determined and controlled.   
     
     
         2 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Zd 2 ), the material flow velocity (v p ) and the voltage (U B ) between the nozzle ( 30 ) and the electrode ( 36 ) are controlled.   
     
     
         3 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Zd 2 ), the temperature (T) of the material flow ( 42 ) and the material flow velocity (v p ) are controlled.   
     
     
         4 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Z 2 ), the temperature (T) and the voltage (U B ) between the nozzle ( 30 ) and the electrode ( 36 ) are controlled.   
     
     
         5 . The method as claimed in  claim 1 ,
 in which, as target variables (Z 1 , Z 2 , Z 3 ), the temperature (T) of the material flow ( 42 ),   the material flow velocity (v p ) and the voltage (U B ) between the nozzle ( 30 ) and the electrode ( 36 ) are controlled.   
     
     
         6 . The method as claimed in one or more of  claims 1 ,  2 ,  3 ,  4  and  5 
 in which the current intensity (I B ) between the nozzle ( 30 ) and the electrode ( 36 ) and/or the gas flow rates ({dot over (m)} H2 , {dot over (m)} Ar ) of the nozzle ( 30 ) are varied as control variables (R 1 , R 2 , R 3 ), in order to keep the target variables (Z 1 , Z 2 , Z 3 ) in a specific tolerant range or constant. 
 
     
     
         7 . The method as claimed in one or more of  claims 1  to  6 , in which the current intensity (I B ) is increased or lowered as a control variable (R 1 , R 2 , R 3 ). 
     
     
         8 . The method as claimed in one or more of  claims 1  to  7 , in which the gas flow rate ({dot over (m)} Ar , {dot over (m)} H2 ) of the primary gases (argon, helium)
 and/or of the secondary gases (hydrogen, . . . ) of the nozzle ( 30 ) are increased or lowered as at least one control variable (R 1 , R 2 , R 3 ). 
 
     
     
         9 . The method as claimed in one or more of  claims 1  to  8 , in which an HVOF method is used. 
     
     
         10 . The method as claimed in one or more of  claims 1  to  9 , in which a plasma spraying method is used.