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 1,000° 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 method for surface treating a titanium-containing substrate comprising: 
 providing a substrate having a surface comprising titanium;    heating the substrate to a temperature sufficient to diffuse carbon into the titanium and less than about 1,000° F.; and    contacting the surface with a carbon-containing gas for a period of time sufficient to diffuse carbon into the substrate to form a surface layer comprising one or more of carbides and interstitial carbon.    
   
   
       2 . The method of  claim 1 , wherein the substrate is a titanium-containing 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 superalloys.  
   
   
       3 . The method of  claim 1 , further comprising cleaning the substrate prior to contacting the substrate with the carbon-containing gas.  
   
   
       4 . The method of  claim 1 , wherein the carbon-containing gas includes a gas selected from the group consisting of methane, propane, ethylene gas, acetylene, carbon dioxide, carbon monoxide and combinations thereof.  
   
   
       5 . The method of  claim 4 , wherein the carbon-containing gas further includes a non-reactive gas selected from the group consisting of argon, helium, or hydrogen.  
   
   
       6 . The method of  claim 1 , wherein the contacting step takes place for up to about 1,500 hours.  
   
   
       7 . The method of  claim 6 , wherein the contacting step takes place for up to about 1,000 hours.  
   
   
       8 . An article comprising: 
 a first titanium-containing alloy having a surface layer comprising one or more of carbides and interstitial carbon formed at a temperature less than about 1,000° F., the surface layer having a pre-selected thickness from the surface, and    wherein the surface layer of the substrate has a sufficient amount of carbon and a sufficient thickness to resist fretting when placed in frictional contact with a second metallic alloy.    
   
   
       9 . The article of  claim 8 , wherein the first titanium-containing alloy is 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 superalloys.  
   
   
       10 . The article of  claim 8 , wherein the pre-selected distance is up to about 0.01 inches.  
   
   
       11 . The article of  claim 8 , wherein the pre-selected distance is up to about 0.001 inches.  
   
   
       12 . The article of  claim 8 , wherein the surface of the first titanium-containing alloy has a coefficient of friction of up to about 0.6 when in contact with the second metallic alloy.