Method For Applying A Protective Layer, Component Coated With A Protective Layer, And Gas Turbine Comprising Such A Component

Abstract

A method for applying a protective layer resistant to high-temperature degradation by corrosion and erosion to a base metal, comprises: applying a MCrAlY-based bond layer to the base metal; coating, by overaluminizing with an Al diffusion layer, the bond layer; subjecting the Al diffusion layer ( 14 ) to abrasion treatment so that an outer build-up layer is removed from the Al diffusion layer; and applying a ceramic thermal barrier coating of yttria partially stabilized zirconia to the remaining Al diffusion layer. The ceramic thermal barrier coating is applied to the remaining Al diffusion layer by air plasma spraying. The applied bond layer is subjected to a polishing treatment before being overaluminized such that a surface roughness of Ra≦2 μm is produced at the bond layer.

1 - 9 . (canceled) 
     
     
         10 . A method for applying a protective layer resistant to high-temperature degradation by corrosion and erosion to a base metal ( 11 ), the method comprising:
 applying a MCrAlY-based bond layer ( 12 ) to the base metal ( 11 );   coating, by overaluminizing with an Al diffusion layer ( 14 ), the bond layer ( 12 );   subjecting the Al diffusion layer ( 14 ) to abrasion treatment so that an outer build-up layer ( 14 . 2 ) is removed from the Al diffusion layer ( 14 ); and   applying a ceramic thermal barrier coating ( 13 ) of yttria partially stabilized zirconia to the remaining Al diffusion layer ( 14 ),   wherein the ceramic thermal barrier coating ( 13 ) is applied to the remaining Al diffusion layer ( 14 ) by air plasma spraying, wherein the applied bond layer ( 12 ) is subjected to a polishing treatment before being overaluminized such that a surface roughness of Ra≦2 μm is produced at the bond layer ( 12 ).   
     
     
         11 . The method according to  claim 10 , wherein the bond layer ( 12 ) is applied to the base metal ( 11 ) by a thermal spraying method. 
     
     
         12 . The method according to  claim 10 , wherein the Al diffusion layer ( 14 ) is subjected to a polishing treatment after the abrasion treatment such that a surface roughness of Ra≦2 μm is produced at the remaining Al diffusion layer ( 14 ). 
     
     
         13 . The method according to  claim 10 , wherein a heat treatment is carried out after overaluminizing the bond layer ( 12 ) and before abrading the Al diffusion layer ( 14 ) in order to influence the mechanical properties of the base metal ( 11 ). 
     
     
         14 . The method according to claim  1 , wherein during overaluminizing an inner diffusion zone ( 14 . 1 ) with an Al content of about 20 weight percent is produced in the Al diffusion layer ( 14 ) and the outer build-up layer ( 14 . 2 ) with an Al content of about 30 weight percent is produced on the diffusion zone ( 14 . 1 ), and in that the outer build-up layer ( 14 . 2 ) of the Al diffusion layer ( 14 ) is removed by abrasion treatment until the Al content in a surface of the remaining Al diffusion layer ( 14 ) amounts to more than 18 weight percent and less than 30 weight percent. 
     
     
         15 . A component part ( 10 ) for use in a hot gas region of a gas turbine ( 1 ), the component part ( 10 ) having a surface that is at least partially provided with a protective layer resistant to high-temperature degradation by corrosion and erosion and applied by the method according to  claim 10 . 
     
     
         16 . A gas turbine ( 1 ) with a hot gas region, the gas turbine having a component part ( 10 ) according to  claim 15 .