Oxidation protected blade and method of manufacturing

Abstract

The surface of a gas turbine blade is machined with a material-removing tool and simultaneously, an anti-oxidation coating is deposited on the surface using eletrospark deposition.

1 . A method of providing oxidation protection to an airfoil blade of a gas turbine engine, the method comprising the steps of: 
 providing the airfoil blade with a first anti-oxidation coating applied to an outer surface thereof;    adjusting a tip clearance dimension of the airfoil blade by grinding a tip portion of the blade, thereby at least partially removing a layer; and then    depositing a second oxidation-resistant coating to at least said ground tip portion using electrospark deposition.    
   
   
       2 . The method of  claim 1  wherein the oxidation-resistant coating material applied by electrospark deposition is MCrAlY.  
   
   
       3 . The method of  claim 1  wherein the tip portion includes an edge of a pressure side of the blade.  
   
   
       4 . The method of  claim 1  wherein the steps of grinding and electrospark deposition are repeated, in sequence, at least once.  
   
   
       5 . The method of  claim 4  wherein said repeated grinding step partially removes a coating layer previously deposited by said electrospark deposition.  
   
   
       6 . The method of  claim 1  wherein the step of electrospark deposition includes applying said second coating in at least some areas where said first coating remains.  
   
   
       7 . The method of  claim 1  further comprising providing additional second coating material at a gap at the tip portion of the blade.  
   
   
       8 . The method of  claim 1  further comprising superposing multiple layers of said second coating on top of one another.  
   
   
       9 . The method of  claim 1  further comprising providing a recessed portion of the tip portion with additional layers of said second coating relative to non-recessed portions of the blade.  
   
   
       10 . A method of providing oxidation protection to a coated airfoil blade of a gas turbine engine, the method comprising the steps of: 
 removing at least a portion of a coating from a tip portion of the blade; and    then    depositing an oxidation-resistant coating to said tip portion using electrospark deposition.    
   
   
       11 . The method of  claim 10  wherein a portion of a parent material of the blade is also removed with the at least a portion of the coating.  
   
   
       12 . The method of  claim 11  wherein the parent material and coating are removed to adjust a tip clearance height of the blade.  
   
   
       13 . The method of  claim 10  wherein the step of removing is performed by grinding.  
   
   
       14 . The method of  claim 10  wherein the oxidation-resistant coating is MCrAlY.  
   
   
       15 . The method of  claim 10  wherein the oxidation-resistant coating applied to at least an edge of the tip portion adjacent a pressure side of blade.