Abstract: A method for bonding airfoil sections includes aligning upper and stub airfoil sections having upper airfoil pressure and suction sides and stub airfoil pressure and suction sides respectively, pressing together upper and stub airfoil cross sections at upper and stub airfoil distal ends of the upper and stub airfoil sections respectively, and then resistance welding, preferably solid state resistance welding, the upper and stub airfoil sections together along the upper and stub airfoil cross sections by passing electrical current across the upper and stub airfoil cross sections. The upper and stub airfoil sections may be clamped between pressure and suction side upper airfoil electrodes and between the stub airfoil pressure and suction sides respectively. The method may be performed while the stub airfoil section is attached to an airfoil carrier such as a rotor disk rim, a gas turbine engine drum, or a gas turbine engine blade platform.

Abstract: A method for bonding airfoil sections includes aligning upper and stub airfoil sections having upper airfoil pressure and suction sides and stub airfoil pressure and suction sides respectively, pressing together upper and stub airfoil cross sections at upper and stub airfoil distal ends of the upper and stub airfoil sections respectively, and then resistance welding, preferably solid state resistance welding, the upper and stub airfoil sections together along the upper and stub airfoil cross sections by passing electrical current across the upper and stub airfoil cross sections. The upper and stub airfoil sections may be clamped between pressure and suction side upper airfoil electrodes and between the stub airfoil pressure and suction sides respectively. The method may be performed while the stub airfoil section is attached to an airfoil carrier such as a rotor disk rim, a gas turbine engine drum, or a gas turbine engine blade platform.

Abstract: A method of producing an airfoil including the steps of providing a first preform having a metallic powder of a first alloy, the first preform defining an airfoil body having curved pressure and suction sides. A tip cap is disposed between the pressure and suction sides of the airfoil at a radially outer end of the airfoil body. A partial height squealer tip extends radially outwards from the tip cap to provide a second preform that is a metallic powder of a second alloy different from the first alloy. The tip cap is formed in the shape of an extension of the squealer tip. The first and second preforms are sintered to consolidate the metal powders. An airfoil according to the method is also disclosed.

Abstract: A method for restoring a length of at least one of a master rod and an articulating rod, the method including determining a length of the rod, if the rod is within an acceptable length, cleaning the rod, applying a masking material to a part of the rod to be protected, grit blasting the part of the rod not protected by the masking material, and applying a thermal spray to the part of the rod not protected by the masking material to increase the length of the rod.

Abstract: A method for restoring a piston pin and/or an articulating pin after operating in an engine, the method includes removing material from the pin so that the pin has a concentric shape, conditioning the pin to accept application of a new material, and plating the outer diameter of the pin so as to restore the pin to near original dimensions.

Abstract: A method for restoring a length of at least one of a master rod and an articulating rod, the method including determining a length of the rod, if the rod is within an acceptable length, cleaning the rod, applying a masking material to a part of the rod to be protected, grit blasting the part of the rod not protected by the masking material, and applying a thermal spray to the part of the rod not protected by the masking material to increase the length of the rod.

Abstract: An electrochemical process for selectively stripping at least one coating from the surface of a substrate is disclosed. The substrate (often a turbine engine component) is immersed in a composition through which electrical current flows. The composition includes a halide salt, such as sodium chloride, ammonium chloride, and potassium chloride. In preferred embodiments, the electrical current is direct current (DC). The process is especially useful for selectively removing portions of diffusion aluminide coatings. For example, the additive layer can efficiently be removed, without substantially affecting the underlying diffusion layer or substrate. Related stripping compositions and apparatuses are also described.

Abstract: A process for removing aluminosilicate-based material (e.g., “CMAS”) from a substrate is described. The material is treated with an aqueous composition containing at least one acid having the formula HxAF6, in which A is Si, Ge, Ti, Zr, Al, and Ga; and x is 1-6. Treatment of the substrate is often carried out by immersion in an aqueous bath. The process is also very effective for removing CMAS-type material from cavities in the substrate, e.g., cooling holes in a gas turbine component. Related compositions are also described.

Abstract: An internal coating on an internal passage wall exposed at a passage opening through an article external surface is protected from removal during repair of the article, including removal of at least a portion of an external coating, by a masking assembly disposed about the passage opening. The masking assembly comprises a masking member and a substantially flexible seal, substantially inert to a coating removal medium for the external coating. The masking member is shaped for disposition about the passage opening across a gap between the external surface and the masking member. The substantially flexible seal is disposed across the gap substantially to seal the gap.

Abstract: An airfoil body having a first wall including a plurality of ribs. An outer wall formed of a high temperature foil is attached to the ribs so as to form a plurality of channels. The first wall is protected from hot flowpath gases by the outer wall and by cooling air flowing through the channels.

Abstract: A protected article includes a nickel-base superalloy substrate, an interlayer overlying the substrate, and a protective layer overlying the interlayer. The protective layer has a composition comprising at least one of rhodium, platinum, palladium, and ruthenium. In one composition, palladium is present in an amount of from about 1 to about 41 atomic percent; platinum is present in an amount of about (40+atomic percent palladium) atomic percent for palladium ranging from about 1 atomic percent to about 14 atomic percent and up to about 54 atomic percent for palladium ranging from about 15 atomic percent up to about 41 atomic percent; rhodium is present in an amount of at least about 24 atomic percent; zirconium, hafnium, titanium, and mixtures thereof are present in an amount of from zero up to about 5 atomic percent; and ruthenium is present in an amount of from zero up to about 5 atomic percent, balance impurities.

Abstract: An electrochemical process for selectively stripping at least one coating from the surface of a substrate is disclosed. The substrate (often a turbine engine component) is immersed in a composition through which electrical current flows. The composition includes a halide salt, such as sodium chloride, ammonium chloride, and potassium chloride. In preferred embodiments, the electrical current is direct current (DC). The process is especially useful for selectively removing portions of diffusion aluminide coatings. For example, the additive layer can efficiently be removed, without substantially affecting the underlying diffusion layer or substrate. Related stripping compositions and apparatuses are also described.

Abstract: A process for removing aluminosilicate-based material (e.g., “CMAS”) from a substrate is described. The material is treated with an aqueous composition containing at least one acid having the formula HXAF6, in which A is Si, Ge, Ti, Zr, Al, and Ga; and x is 1-6. Treatment of the substrate is often carried out by immersion in an aqueous bath. The process is also very effective for removing CMAS-type material from cavities in the substrate, e.g., cooling holes in a gas turbine component. Related compositions are also described.

Abstract: A wall structure for a gas turbine engine component is provided which comprises a wall having a first side facing a flow of hot gases and a second side exposed to a source of cooling fluid. The wall has a plurality of holes formed therethrough, and an outer layer disposed on the first side. The holes greatly increase the wetted surface area of the wall exposed to cooling flow.

Abstract: A turbine airfoil is provided having an integral tip cap and a pair of tip walls which extend radially outward past the tip cap to form a squealer tip. A coaxial pair of first and second holes extend through the tip cap and one of the tip walls respectively at an acute inclination angle, with the first hole being disposed so as to direct impingement cooling air on the tip wall having the second hole. A protective layer comprising a high temperature foil is disposed on the tip wall having the second hole therein.

Abstract: An electrochemical stripping method for selectively removing at least one coating from the surface of a substrate is described. The substrate is immersed in an aqueous composition through which electrical current flows. The composition includes an acid having the formula HxAF6, in which “A” is Si, Ge, Ti, Zr, Al, or Ga; and x is 1-6. Various coatings can be removed, such as diffusion or overlay coatings. The method can be used to fully-strip a coating (e.g., from a turbine component), or to partially strip one sublayer of the coating. Related processes and an apparatus are also described.

Abstract: A protected article includes a nickel-base superalloy substrate, an interlayer overlying the substrate, and a protective layer overlying the interlayer. The protective layer has a composition comprising at least one of rhodium, platinum, palladium, and ruthenium. In one composition, palladium is present in an amount of from about 1 to about 41 atomic percent; platinum is present in an amount of about (40+atomic percent palladium) atomic percent for palladium ranging from about 1 atomic percent to about 14 atomic percent and up to about 54 atomic percent for palladium ranging from about 15 atomic percent up to about 41 atomic percent; rhodium is present in an amount of at least about 24 atomic percent; zirconium, hafnium, titanium, and mixtures thereof are present in an amount of from zero up to about 5 atomic percent; and ruthenium is present in an amount of from zero up to about 5 atomic percent, balance impurities.

Abstract: A wall structure for a gas turbine engine component is provided which comprises a wall having a first side facing a flow of hot gases and a second side exposed to a source of cooling fluid. The wall has a plurality of holes formed therethrough, and an outer layer disposed on the first side. The holes greatly increase the wetted surface area of the wall exposed to cooling flow.

Abstract: The present invention provides an airfoil body having a first wall including a plurality of ribs. An outer wall formed of a high temperature foil is attached to the ribs so as to form a plurality of channels. The first wall is protected from hot flowpath gases by the outer wall and by cooling air flowing through the channels.

Abstract: A turbine airfoil is provided having an integral tip cap and a pair of tip walls which extend radially outward past the tip cap to form a squealer tip. A coaxial pair of first and second holes extend through the tip cap and one of the tip walls respectively at an acute inclination angle, with the first hole being disposed so as to direct impingement cooling air on the tip wall having the second hole. A protective layer comprising a high temperature foil is disposed on the tip wall having the second hole therein.