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.

Abstract: The present invention relates to surface hardening of a metal surface of a work piece formed of titanium and titanium alloys. The method comprises the steps of heating the work piece; exposing the metal surface to a nitrogen gas having a partial pressure lower than about 10?2 Pa; and maintaining the work piece in the nitrogen gas so that nitrogen is absorbed onto the surface of the work piece and diffused into the work piece for a desired distance while preventing the formation of nitrides on the surface of the work piece and within the work piece.