Method for repairing monocrystalline materials

Abstract

A method for coating, with a coating material, a monocrystalline substrate surface of a component comprising a monocrystalline alloy includes polishing the monocrystalline substrate surface, transferring the substrate to a vacuum chamber, and heating the entire substrate to a temperature of at least half a melting temperature of the substrate but less than a melting temperature of the substrate. The method further includes applying the coating material in powder form onto the polished monocrystalline substrate surface by vacuum plasma spraying. The powder has a mean particle size in a range of 10 to 200 μm. A pressure in a range of 1 to 200 mbar is set for the vacuum plasma spraying, and an argon atmosphere having a hydrogen content in a range of 10 to 50 vol. % is used as a working gas for the vacuum plasma spraying.

1 . A method for coating, with a coating material, a monocrystalline substrate surface of a component comprising a monocrystalline alloy, the method comprising:
 polishing the monocrystalline substrate surface;   transferring the substrate to a vacuum chamber;   heating the entire substrate to a temperature of at least half a melting temperature of the substrate but less than a melting temperature of the substrate;   applying the coating material in powder form onto the polished monocrystalline substrate surface by vacuum plasma spraying, wherein the powder has a mean particle size in a range of 10 to 200 μm, wherein a pressure in a range of 1 to 200 mbar is set for the vacuum plasma spraying, and wherein an argon atmosphere having a hydrogen content in a range of 10 to 50 vol. % is used as a working gas for the vacuum plasma spraying; and   thereby generating at least one region directly at an interface of the coating material and the polished monocrystalline substrate surface having a same single-crystalline orientation as the substrate.   
     
     
         2 . The method according to  claim 1 , wherein the coating material is identical to a substrate material. 
     
     
         3 . The method according to  claim 2 , wherein the coating material and the substrate material are a monocrystalline nickel-based alloy or a cobalt-based alloy. 
     
     
         4 . The method according to  claim 1 , wherein the entire substrate is heated to at least 700° C. 
     
     
         5 . The method according to  claim 1 , wherein the entire substrate is heated electrically, inductively, or by electromagnetic radiation. 
     
     
         6 . The method according to  claim 1 , wherein the substrate surface is heated by a plasma torch without powder feed. 
     
     
         7 . The method according to  claim 1 , wherein the coated substrate is subsequently subjected to solution annealing, precipitation annealing, and/or pressure-assisted heat treatment for coating. 
     
     
         8 . The method according to  claim 1 , wherein the substrate has at least one cooling hole.