Turbine component thermal barrier coating with crack isolating engineered surface features

Abstract

Thermal barrier coatings (TBCs) for turbine engine components are applied over engineered surface features (ESFs) that are formed in the component substrate or within intermediate layers applied between the substrate and the TBC. The ESFs help anchor the TBC layer and/or localize cracks that are bounded by one or more of the ESFs. During engine operation the ESFs arrest thermal stress-or foreign object damage (FOD)-induced crack propagation within the TBC that might otherwise allow excessive TBC spallation and subsequent thermal exposure damage to the turbine component underlying substrate. In some embodiments, the ESFs are combined with engineered groove features that are formed in the TBC.

1 . A combustion turbine component having a heat insulating outer surface for exposure to combustion gas, comprising:
 a metallic substrate having a substrate surface;   an anchoring layer built upon the substrate surface;   a thermally sprayed or vapor deposited or solution/suspension plasma sprayed thermal barrier coat (TBC), including at least an outer thermal barrier coat (OTBC) layer having an OTBC inner surface applied over and coupled to the anchoring layer and an OTBC outer surface for exposure to combustion gas;   a planform pattern of engineered surface features (ESFs) projecting from the anchoring layer having projection height between approximately 2-75 percent of TBC layers aggregate total thickness; and   a planform pattern of engineered groove features (EGFs) formed into and penetrating the previously applied OTBC layer through the OTBC outer surface, having a groove depth.   
     
     
         2 . The component of  claim 1 , the anchoring layer further comprising:
 a bond coat (BC) layer coupled to a featureless substrate surface;   the ESFs formed in the BC; and   the ESFs defining an aggregate surface area at least 20 percent greater than an equivalent flat surface.   
     
     
         3 . The component of  claim 1 , the anchoring layer further comprising:
 a bond coat (BC) layer coupled to the substrate surface;   the ESFs formed in the substrate; and   the ESFs defining an aggregate surface area at least 20 percent greater than an equivalent flat surface.   
     
     
         4 . The component of  claim 1 , the anchoring layer further comprising:
 a bond coat (BC) layer coupled to the substrate surface;   a thermally sprayed or vapor deposited or solution/suspension plasma sprayed lower thermal barrier coat (LTBC) layer portion in contact with the OTBC layer portion, with the EGFs penetrating into the LTBC layer; and   the ESFs formed in the LTBC portion layer.   
     
     
         5 . The component of  claim 4 , further comprising the LTBC thermally sprayed layer portion having higher thermal conductivity and higher fracture toughness than the OTBC thermally sprayed layer portion. 
     
     
         6 . The component of  claim 1 , further comprising the ESFs and EGFs in respectively defined separate three-dimensional, independently aligned planform patterns across the component. 
     
     
         7 . The component of  claim 1 , further comprising the ESFs and EGFs respectively having repeating three-dimensional planform patterns. 
     
     
         8 . The component of  claim 1 , further comprising the ESFs having a trapezoidal cross section with a pair of first opposed, inwardly sloping lateral walls terminating in a plateau. 
     
     
         9 . The component of  claim 1 , the anchoring layer further comprising:
 a bond coat (BC) layer coupled to the substrate surface;   the ESFs formed in the substrate or the BC layer;   the ESFs defining an aggregate surface area at least 20 percent greater than an equivalent flat surface; and   a rough bond coat layer applied over the BC layer.   
     
     
         10 . A combustion turbine engine comprising the component of  claim 1 , the OTBC outer surface in communication with a combustion path of the engine for exposure to combustion gas. 
     
     
         11 . The engine of  claim 10 , the component comprising a turbine blade, a turbine vane, or a combustion section transition or ring segment. 
     
     
         12 . The component of  claim 1 , the ESFs additively applied as part of the anchoring layer. 
     
     
         13 . A method for making a combustion turbine component having a heat insulating outer surface for exposure to combustion gas, comprising:
 providing a metallic substrate having a substrate surface;   building an anchoring layer upon the substrate surface;   forming in the anchoring layer a planform pattern of engineered surface features (ESFs) projecting therefrom;   forming a thermally sprayed or vapor deposited or solution/suspension plasma deposited thermal barrier coat (TBC) layer coupled to the anchoring layer, including at least an outer thermal barrier coat (OTBC) layer having an OTBC inner surface applied over and coupled to the anchoring layer and an OTBC outer surface for exposure to combustion gas; and   forming a planform pattern of engineered groove features (EGFs) into and penetrating the previously applied OTBC layer through the OTBC outer surface, having a groove depth;   said formed ESFs having projection height between approximately 2-75 percent of TBC layers aggregate total thickness.   
     
     
         14 . The method of  claim 13 , the anchoring layer formation further comprising:
 forming a thermally sprayed bond coat (BC) layer on the substrate surface; and   forming a thermally sprayed or vapor deposited or suspension/solution plasma sprayed lower thermal barrier coat (LTBC) layer on the BC layer prior to forming the OTBC layer on top of the LTBC layer portion;   
       the LTBC and OTBC layers constituting a least a portion of the TBC layers aggregate total thickness. 
     
     
         15 . The method of  claim 13 , further comprising forming additively applied ESFs as part of the anchoring layer. 
     
     
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