Combined effusion and thick TBC cooling method

Abstract

A method for combined effusion and thick TBC cooling comprises a providing a substrate, depositing a thick TBC onto the substrate and laser drilling an array of effusion holes through the TBC coated substrate. The thick TBC has a columnar crack structure, which gives compliance and spall resistance. The microstructure of the segmentation microcracked TBC reduces cracking and chipping of the TBC during effusion hole laser drilling.

1 . A method of cooling comprising the steps of: 
 providing a substrate;    depositing a thermal barrier coating to a thickness of at least about 0.020 inches onto said substrate to produce a coated material; and    forming an array of effusion cooling holes through said coated material.    
   
   
       2 . The method of  claim 1 , wherein said step of depositing comprises plasma spraying such that said thermal barrier coating has a columnar crack microstructure comprising a plurality of segmentation microcracks.  
   
   
       3 . The method of  claim 1 , wherein said step of depositing comprises electron beam evaporation-physical vapor deposition such that said thermal barrier coating has a microstructure comprising a columnar grain structure with intercolumnar gaps.  
   
   
       4 . The method of  claim 1 , further comprising a step of applying a bond coat, such that said bond coat is between said substrate and said thermal barrier coating.  
   
   
       5 . The method of  claim 1 , wherein said step of depositing comprises depositing to a thickness between about 0.020 and about 0.100 inches.  
   
   
       6 . The method of  claim 1 , wherein said step of depositing comprises depositing to a thickness between about 0.020 and about 0.050 inches.  
   
   
       7 . The method of  claim 1 , wherein said step of forming comprises laser drilling through said coated material.  
   
   
       8 . The method of  claim 7 , wherein said laser drilling comprises a two-step laser drilling process and wherein a first step produces a counterbore.  
   
   
       9 . The method of  claim 1 , wherein said substrate comprises a combustor.  
   
   
       10 . The method of  claim 1 , wherein said step of depositing comprises depositing cubic zirconia stabilized with about 18% to about 22% by weight yttria.  
   
   
       11 . The method of  claim 1 , wherein said thermal barrier coating comprises a material selected from the group consisting of stabilized cubic zirconia, stabilized cubic hafnia, stabilized tetragonal zirconia, stabilized tetragonal hafnia, yttria-stabilized cubic zirconia, yttria-stabilized cubic hafnia, yttria-stabilized tetragonal zirconia, and yttria-stabilized tetragonal hafnia.  
   
   
       12 . A method of cooling a combustor comprising the steps of: 
 applying a bond coat to said combustor;    depositing a thermal barrier coating to a thickness greater than about 0.020 inch onto said bond coat such that a segmentation microcracked coating is produced; and    machining at least one effusion hole through said segmentation microcracked coating and said combustor.    
   
   
       13 . The method of  claim 12 , wherein said step of machining comprises a first step of laser drilling a counterbore into said segmentation microcracked coating and a second step of laser drilling through said combustor.  
   
   
       14 . The method of  claim 12 , wherein said step of machining comprises stationary percussion laser drilling at an angle ranging from 15° to 90° relative to a surface of said combustor.  
   
   
       15 . The method of  claim 12 , wherein said step of machining comprises laser drilling at least one effusion hole having a diameter between about 0.01 and about 0.03 inches.  
   
   
       16 . The method of  claim 12 , wherein said step of applying comprises plasma spraying a material selected from the group consisting of NiCrAlY and NiCoCrAlY.  
   
   
       17 . The method of  claim 12 , wherein said step of depositing comprises depositing to a thickness between about 0.020 and about 0.100 inch.  
   
   
       18 . The method of  claim 12 , wherein said step of depositing comprises depositing a stabilized cubic zirconia.  
   
   
       19 . The method of  claim 18 , wherein said stabilized cubic zirconia has at least about 18% by weight yttria.  
   
   
       20 . The method of  claim 12 , wherein said thermal barrier coating comprises at least one stabilizing oxide and a material selected from the group consisting of zirconia and hafnia.  
   
   
       21 . The method of  claim 20 , wherein said at least one stabilizing oxide is selected from the group consisting of zirconia, hafnia, yttria, scandia, ytterbia, neodymia, samaria, gadolinia, magnesia, calcia, ceria, and tantala.  
   
   
       22 . The method of  claim 21 , wherein the concentration of said at least one stabilizing oxide is between the minimum solubility limit for full-stabilization of the tetragonal phase and the maximum solubility limit for full-stabilization of the cubic phase.  
   
   
       23 . The method of  claim 12 , wherein said step of depositing comprises a process selected from the group consisting of plasma spray, high velocity oxyfuel, and electron beam evaporation-physical vapor deposition.  
   
   
       24 . A method of cooling a combustor comprising the steps of: 
 applying a bond coat to said combustor;    depositing a thermal barrier coating onto said bond coat such that a segmentation microcracked coating having a thickness between about 0.020 and about 0.050 inches is produced, said thermal barrier coating comprising a material selected from the group consisting of stabilized cubic zirconia, stabilized cubic hafnia, stabilized tetragonal zirconia, stabilized tetragonal hafnia, yttria-stabilized cubic zirconia, yttria-stabilized cubic hafnia, yttria-stabilized tetragonal zirconia, and yttria-stabilized tetragonal hafnia; and    laser drilling at least one effusion hole through said segmentation microcracked coating and said combustor.    
   
   
       25 . The method of  claim 24 , wherein said thermal barrier coating comprises cubic zirconia stabilized with about 18% and about 22% by weight Yttria.  
   
   
       26 . A method of cooling a combustor comprising the steps of: 
 applying a bond coat to said combustor;    depositing a thermal barrier coating onto said bond coat such that a columnar grained coating having intercolumnar gaps is produced, said columnar grained coating having a thickness between about 0.020 and about 0.050 inches, said thermal barrier coating comprising a material selected from the group consisting of stabilized cubic zirconia, stabilized cubic hafnia, stabilized tetragonal zirconia, stabilized tetragonal hafnia, yttria-stabilized cubic zirconia, yttria-stabilized cubic hafnia, yttria-stabilized tetragonal zirconia, and yttria-stabilized tetragonal hafnia; and    laser drilling at least one effusion hole through said columnar grained coating and said combustor.    
   
   
       27 . A method of forming an effusion hole comprising the steps of: 
 providing a substrate having a thermal barrier coating, said thermal barrier coating having a segmented columnar structure and a thickness between about 0.020 and about 0.100 inches; and    laser drilling at least one effusion hole through said substrate.    
   
   
       28 . The method of  claim 27 , wherein said step of laser drilling comprises stationary percussion laser drilling at an angle between about 15° and about 45° relative to a surface of said substrate.  
   
   
       29 . The method of  claim 27 , wherein said step of laser drilling comprises percussion on-the-fly laser drilling at an angle between about 15° and about 45° relative to a surface of said substrate.  
   
   
       30 . The method of  claim 27 , wherein said step of laser drilling comprises laser drilling a counterbore.  
   
   
       31 . A method of cooling a substrate comprising the steps of: 
 depositing a thermal barrier coating on said substrate to a thickness of at least about 0.02 inches such that a coated material is produced; and    drilling at least one effusion hole through said coated material.    
   
   
       32 . The method of  claim 31 , wherein said step of depositing comprises forming a microstructure having a plurality of segmentation microcracks.  
   
   
       33 . The method of  claim 31 , wherein said step of depositing comprises forming a microstructure having a plurality of columnar grains with intercolumnar gaps.  
   
   
       34 . The method of  claim 31 , wherein said step of drilling comprises laser drilling.  
   
   
       35 . The method of  claim 31 , wherein said step of depositing comprises plasma spraying.  
   
   
       36 . The method of  claim 31 , wherein said step of depositing comprises electron beam evaporation-physical vapor deposition.  
   
   
       37 . An apparatus for a gas turbine engine comprising: 
 a combustor having a segmentation microcracked thermal barrier coating and a plurality of effusion holes therethrough, said segmentation microcracked thermal barrier coating having a thickness between about 0.020 and about 0.100 inches.    
   
   
       38 . The apparatus of  claim 37 , wherein said segmentation microcracked thermal barrier coating comprises a material selected from the group consisting of stabilized cubic zirconia, stabilized cubic hafnia, stabilized tetragonal zirconia, stabilized tetragonal hafnia, yttria-stabilized cubic zirconia, yttria-stabilized cubic hafnia, yttria-stabilized tetragonal zirconia, and yttria-stabilized tetragonal hafnia.  
   
   
       39 . The apparatus of  claim 37 , wherein said segmentation microcracked thermal barrier coating comprises about 18% to about 22% by weight yttria.