Atomic layer deposition for turbine components

Abstract

A method and superalloy component for depositing a layer of material onto gas turbine engine components by atomic layer deposition. A superalloy component may have a ceramic thermal barrier coating on at least a portion of its surface, comprising a superalloy substrate and a bonding coat; and aluminum oxide (Al 2 O 3 ) layer may be deposited on top of an yttria-stabilized zirconia layer and form a bonding coat by atomic layer deposition. The yttria-stabilized zirconia layer may have a plurality of micron sized gaps extending from the top surface of the ceramic coating towards the substrate and defining a plurality of columns of the yttria-stabilized zirconia layer. Also, atomic layer deposition may be used to lay an aluminum oxide (Al 2 O 3 ) layer over a tantalum oxide (Ta 2 O 5 ) layer on a silicon-based substrate. Using atomic layer deposition to coat the gas turbine engine components permits conformal coating of the columnar surface to permit gap expansion and contraction without sintering of the columnar surface or spalling of the coating, and form an oxidation resistant bonding coat.

1 . A superalloy component having a ceramic thermal barrier coating on at least a portion of its surface, comprising: 
 a superalloy substrate;    a ceramic thermal barrier coating overlying the superalloy substrate;    a first coating layer overlying the ceramic thermal barrier coating;    the first coating layer having a thickness from about 5 nm to 5000 nm microns;    the ceramic thermal barrier coating having a plurality of gaps extending from the top surface of the ceramic thermal barrier coating towards the substrate and defining a plurality of columns of the ceramic thermal barrier coating; and    a second coating layer overlying the first coating layer and conformally coating the plurality of gaps;    wherein the second coating layer is deposited over the first coating layer by atomic layer deposition.    
   
   
       2 . The superalloy component of  claim 1 , further comprising a bonding coat located between the superalloy substrate and the first coating layer; 
 wherein the bonding coat is deposited over the superalloy substrate by atomic layer deposition.    
   
   
       3 . The superalloy component of  claim 1 , wherein the plurality of gaps are micron sized gaps.  
   
   
       4 . The superalloy component of  claim 1 , wherein the plurality of gaps are sub-micron sized gaps.  
   
   
       5 . The superalloy component of  claim 1 , wherein the first coating layer and the second coating layer are selected from the group consisting of oxides, carbides, nitrides, suicides, and metals.  
   
   
       6 . The superalloy component of  claim 5 , wherein the oxides are selected from the group consisting of Al.sub.2O.sub.3, Cr.sub.2O.sub.3, Sc.sub.2O.sub.3, SiO.sub.2, ZrO.sub.2, and Ta.sub.2O.sub.5. HfO.sub.2, TiO.sub.2, Ln.sub.2O.sub.3, MgO, SrO, and alloys and compounds thereof.  
   
   
       7 . The superalloy component of  claim 5 , wherein the nitrides are selected from the group consisting of TaN, ZrN, HfN, TiN, Si.sub.3N.sub.4 and alloys and compounds thereof.  
   
   
       8 . The superalloy component of  claim 5 , wherein the carbides are selected from the group consisting of SiC, TaC, ZrC, HfC and alloys and compounds thereof.  
   
   
       9 . The superalloy component of  claim 5 , wherein the suicides are selected from the group consisting of MoSi.sub.2, Mo.sub.5Si.sub.3, TaSi.sub.2, Ta.sub.5Si.sub.3, and alloys and compounds thereof.  
   
   
       10 . The superalloy component of  claim 5 , wherein the metals are selected from the group consisting of Pt, Ru, Rd, Ir, and alloys and compounds thereof.  
   
   
       11 . A method for coating nickel-based superalloy gas turbine components, comprising: 
 depositing an yttria-stabilized zirconia layer onto a nickel superalloy turbine component, by electron beam plasma vapor deposition, such that the yttria-stabilized zirconia layer is in the form of columnar grains; and    depositing an inorganic layer, by atomic layer deposition, onto the yttria-stabilized zirconia layer, such that the inorganic layer is uniform and conformal.    
   
   
       12 . The method of  claim 11 , further comprising depositing a bonding coat onto the nickel superalloy turbine component, by atomic layer deposition, before depositing the yttria-stabilized zirconia layer.  
   
   
       13 . The method of  claim 11 , wherein the inorganic layer is selected from the group consisting of aluminum oxide (Al.sub.2O.sub.3), tantalum carbide (TaC), tantalum oxide (Ta.sub.2O.sub.5), hafnium oxide (HfO.sub.2), mixtures thereof, nano-laminates thereof, and alloys thereof.  
   
   
       14 . The method of  claim 11 , wherein the inorganic layer is selected from the group consisting of silicon carbide (SiC), silicon nitride (Si.sub.3N.sub.4), oxycarbides, carbonitrides, mixtures thereof, nano-laminates thereof, and alloys thereof.  
   
   
       15 . The method of  claim 11 , wherein the nickel-based superalloy gas turbine component comprises an article selected from the group consisting of a turbine blade, a turbine vane, a combustor fuel nozzle, and a combustor shield.  
   
   
       16 . The method of  claim 11 , wherein the inorganic layer comprises platinum.  
   
   
       17 . A method for coating a substrate comprising: 
 etching chemically a thermal barrier coating such that the thermal barrier coating is in the form of columnar grains; and    depositing an inorganic layer, by atomic layer deposition, onto the thermal barrier coating, such that the inorganic layer is uniform and conformal.    
   
   
       18 . The method of  claim 17 , wherein the inorganic layer is selected from the group consisting of aluminum oxide (Al.sub.2O.sub.3), tantalum carbide (TaC), hafnium oxide (HfO.sub.2), mixtures thereof, nano-laminates thereof, and alloys thereof.  
   
   
       19 . The method of  claim 17 , wherein the inorganic layer is selected from the group consisting of silicon carbide (SiC), silicon nitride (Si.sub.3N.sub.4), oxycarbides, carbonitrides, mixtures thereof, nano-laminates thereof, and alloys thereof.