Titanium treatment to minimize fretting

Abstract

A method for surface treating a titanium gas turbine engine component. The method includes providing a gas turbine engine component having a titanium-containing surface. The component is heated to a temperature sufficient to diffuse carbon into the titanium and below 1000° F. The surface is contacted with a carbon-containing gas to diffuse carbon into the surface to form carbides. Thereafter, the carbide-containing surface is coated with a lubricant comprising a binder and a friction modifier. The binder preferably including titanium oxide and the friction modifier preferably including tungsten disulfide. The coefficient of friction between the surface and another titanium-containing surface is less than about 0.6 in high altitude atmospheres.

1 . A gas turbine engine component comprising:
 a compressor disk and an airfoil in frictional contact, where one or both of the compressor disk and airfoil comprises a titanium-containing alloy having a surface layer comprising one or more of carbides and interstitial carbon, the surface layer having a pre-selected thickness from the surface, and   wherein the surface layer has a sufficient amount of carbon and a sufficient thickness to resist fretting between the compressor disk and airfoil.   
   
   
       2 . The component of  claim 1 , wherein the compressor disk comprises an alloy selected from the group consisting of Ti-6-4, Ti-17, Ti-6-2-4-2, and titanium-containing nickel-based superalloys. 
   
   
       3 . The component of  claim 1 , wherein the airfoil comprises an alloy selected from the group consisting of Ti-6-4, Ti-4-4-2, Ti-6-2-4-2, Ti-8-1-1 and titanium-containing nickel-based superalloys. 
   
   
       4 . The component of  claim 1 , wherein both the compressor disk and airfoil comprise the surface layer. 
   
   
       5 . The alloy of  claim 1 , wherein the pre-selected distance is up to about 0.01 inches. 
   
   
       6 . The alloy of  claim 5 , wherein the pre-selected distance is up to about 0.001 inches. 
   
   
       7 . The alloy of  claim 1 , wherein a coefficient of friction of up to about 0.6 is present between the compressor disk and airfoil. 
   
   
       8 . A gas turbine engine component comprising:
 a titanium-containing surface having a surface layer containing one or more of carbides and interstitial carbon, the surface further comprising a lubricant coating having a binder and a friction modifier; and   wherein the coefficient of friction between the surface and another titanium-containing surface is less than about 0.6 in high altitude atmospheres.   
   
   
       9 . The component of  claim 8 , wherein the component is selected from the group consisting of a compressor disk and an airfoil. 
   
   
       10 . The component of  claim 8 , wherein the friction modifier comprises a material selected from the group consisting of tungsten sulfide, bismuth telluride, bismuth oxide and combinations thereof. 
   
   
       11 . The component of  claim 10 , wherein the friction modifier comprises tungsten sulfide. 
   
   
       12 . The component of  claim 8 , wherein the binder comprises a material selected from the group consisting of titanium oxide, aluminum phosphate and combinations thereof. 
   
   
       13 . The component of  claim 12 , wherein the binder comprises titanium oxide. 
   
   
       14 . The component of  claim 8 , wherein the coefficient of friction between the surface and another titanium-containing surface is less than about 0.4 in high altitude atmospheres. 
   
   
       15 . The component of  claim 8 , wherein the coefficient of friction between the surface and another titanium-containing surface is less than about 0.2 in high altitude atmospheres. 
   
   
       16 . The component of  claim 8 , wherein the high altitude atmospheres include up to about 800° F. 
   
   
       17 . The component of  claim 8 , wherein the high altitude atmospheres include an atmosphere substantially devoid of water vapor. 
   
   
       18 . The component of  claim 8 , wherein the titanium-containing surface includes an 5 alloy selected from the group consisting of Ti-6-4, Ti-17, Ti-4-4-2, Ti-6-2-4-2, Ti-8-1-1 and titanium-containing nickel-based superalloys.