Method of manufacturing or repairing a coating on a metallic substrate

Abstract

The invention provides a method of manufacturing or repairing a coating on a metallic substrate. Production of said coating comprises forming a pre-layer on the substrate or on a sub-layer of the coating placed on the substrate by applying one or more layers of a paint containing at least one metal selected from the group constituted by platinum class metals (platinoids) and chromium. Application to the formation or localized repair of a thermal barrier on a superalloy turbo engine part.

1 . A method of manufacturing or repairing a coating forming a thermal barrier on a superalloy substrate, wherein said coating comprises a binding sub-layer formed by an MCrAlY alloy, M being a metal selected from the group consisting of nickel, cobalt, iron and a mixture of said metals, said binding sub-layer being modified by forming a pre-layer on a surface of said binding sub-layer by:
 first applying one or more layers of a paint including platinum class metals (platinoids) to the binding sub-layer, and   second, performing diffusion heat treatment of the one or more layers of paint.   
   
   
       2 . A method according to  claim 1 , wherein said metal is platinum. 
   
   
       3 . A method according to  claim 1 , wherein said pre-layer is formed with a thickness within a range of 1 μm to 30 μm. 
   
   
       4 . A method according to  claim 1 , wherein said pre-layer is formed by applying said paint using a brush, a spray gun, a pad, and/or by immersion (dip-coating). 
   
   
       5 . A method according to  claim 1 , wherein said thickness is within a range of 2 μm to 10 μm. 
   
   
       6 . A method according to  claim 1 , wherein said sub-layer comprises NiAl. 
   
   
       7 . A method according to  claim 1 , wherein said sub-layer is based on an aluminide. 
   
   
       8 . A method according to  claim 1 , wherein said paint is a suspension of solid material in a liquid, said solid material being a metal powder of said at least one metal. 
   
   
       9 . A method according to  claim 8 , wherein said liquid is water-based. 
   
   
       10 . A method according to  claim 8 , wherein said liquid is oil based. 
   
   
       11 . A method according to  claim 8 , wherein said liquid is based on an hydrocarbon mixture.