Abstract: Methods for cleaning a superalloy substrate having engine deposits on its surface are provided. The method may include applying a permanganate solution onto the surface of the superalloy substrate, and applying a ferric chloride based cleaning composition onto the surface of the superalloy substrate. The ferric chloride based cleaning composition includes ferric chloride and at least one of nitric acid and phosphoric acid, such as within a solvent system (e.g., an aqueous solution including water).

Abstract: Methods for cleaning a superalloy substrate having engine deposits on its surface are provided. The method may include applying a permanganate solution onto the surface of the superalloy substrate, and applying a ferric chloride based cleaning composition onto the surface of the superalloy substrate. The ferric chloride based cleaning composition includes ferric chloride and at least one of nitric acid and phosphoric acid, such as within a solvent system (e.g., an aqueous solution including water).

Abstract: A leading edge structure for use in an aerospace vehicle includes a body having a flowpath surface which defines a leading edge adapted to face an air flow during operation, and an opposed inner surface. The body is segmented into a plurality of portions having varying thermal properties and/or mechanical discontinuities, so as to promote stress concentrations in ice attached to the flowpath surface.

Abstract: A leading edge structure for use in an aerospace vehicle includes a body having a flowpath surface which defines a leading edge adapted to face an air flow during operation, and an opposed inner surface. The body is segmented into a plurality of portions having varying thermal properties and/or mechanical discontinuities, so as to promote stress concentrations in ice attached to the flowpath surface.

Abstract: A process for selectively stripping a coating from a component of a turbomachine, and particularly a coating having a ceramic matrix that contains metallic particles dispersed therein that render the coating more difficult to remove from the component after the component has been subjected to elevated temperatures during operation of the turbomachine. The process generally includes immersing the component in an aqueous solution containing ferric chloride, nitric acid, and phosphoric acid, for a duration sufficient to attack the metallic particles in the coating. The component is then removed from the aqueous solution and its surface rinsed of the aqueous solution. The immersing and removing steps are then sequentially repeated a sufficient number of times to sufficiently attack the metallic particles to enable the coating to be mechanically removed from the component.

Abstract: The present invention provides a method for preparing an electroless nickel coating composition that includes (a) coating a substrate with an electroless nickel coating to provide a coated substrate; and (b) subjecting the coated substrate to a heating protocol comprising heating to a temperature in a range from about 550° C. to about 700° C. for a period of from about 7 to about 30 hours. An article made from the method is also provided.

Abstract: A leading edge structure for use in an aerospace vehicle includes a body having a flowpath surface which defines a leading edge adapted to face an air flow during operation; and a metallic icephobic plating comprising nickel applied to at least a portion of the flowpath surface.

Abstract: A method and cleaning composition for removing engine deposits from turbine components, in particular turbine disks and turbine shafts. This method comprises the following steps: (a) providing a turbine component having a surface with engine deposits thereon, wherein the turbine component comprises a nickel and/or cobalt-containing base metal; and (b) treating the surface of the turbine component with a cleaning composition to convert the engine deposits thereon to a removable smut without substantially etching the base metal of the turbine component. The cleaning composition comprises an aqueous solution that is substantially free of acetic acid and comprising: a nitrate ion source in an amount, by weight of the nitrate ion, of from about 470 to about 710 grams/liter; and a bifluoride ion source in an amount, by weight of the bifluoride ion, of from about 0.5 to about 15 grams/liter.

Abstract: A method and cleaning composition for removing engine deposits from turbine components, in particular turbine disks and turbine shafts. This method comprises the following steps: (a) providing a turbine component having a surface with engine deposits thereon, wherein the turbine component comprises a nickel and/or cobalt-containing base metal; and (b) treating the surface of the turbine component with a cleaning composition to convert the engine deposits thereon to a removable smut without substantially etching the base metal of the turbine component. The cleaning composition comprises an aqueous solution that is substantially free of acetic acid and comprising: a nitrate ion source in an amount, by weight of the nitrate ion, of from about 470 to about 710 grams/liter; and a bifluoride ion source in an amount, by weight of the bifluoride ion, of from about 0.5 to about 15 grams/liter.

Abstract: A leading edge structure for use in an aerospace vehicle includes a body having a flowpath surface which defines a leading edge adapted to face an air flow during operation; and a metallic icephobic plating comprising nickel applied to at least a portion of the flowpath surface.

Abstract: A leading edge structure for use in an aerospace vehicle includes a body having a flowpath surface which defines a leading edge adapted to face an air flow during operation, and an opposed inner surface. The body is segmented into a plurality of portions having varying thermal properties and/or mechanical discontinuities, so as to promote stress concentrations in ice attached to the flowpath surface.

Abstract: A process for selectively stripping a coating from a component of a turbomachine, and particularly a coating having a ceramic matrix that contains metallic particles dispersed therein that render the coating more difficult to remove from the component after the component has been subjected to elevated temperatures during operation of the turbomachine. The process generally includes immersing the component in an aqueous solution containing ferric chloride, nitric acid, and phosphoric acid, for a duration sufficient to attack the metallic particles in the coating. The component is then removed from the aqueous solution and its surface rinsed of the aqueous solution. The immersing and removing steps are then sequentially repeated a sufficient number of times to sufficiently attack the metallic particles to enable the coating to be mechanically removed from the component.

Abstract: A method for selectively removing an aluminide coating from at least one surface of a metal-based substrate by: (a) contacting the surface of the substrate with at least one stripping composition comprising nitric acid at a temperature less than about 20° C. to degrade the coating without damaging the substrate; and (b) removing the degraded coating without damaging the substrate. Also disclosed is a method for replacing a worn or damaged aluminide coating on at least one surface of a metal-based substrate by selectively removing the coating using the above steps, and then applying a new aluminide coating to the surface of the substrate. Turbine engine parts, such as high-pressure turbine blades, treated using the above methods are also disclosed.

Abstract: A method and cleaning composition for removing engine deposits from turbine components, in particular turbine disks and turbine shafts. This method comprises the following steps: (a) providing a turbine component having a surface with engine deposits thereon, wherein the turbine component comprises a nickel and/or cobalt-containing base metal; and (b) treating the surface of the turbine component with a cleaning composition to convert the engine deposits thereon to a removable smut without substantially etching the base metal of the turbine component. The cleaning composition comprises an aqueous solution that is substantially free of acetic acid and comprising: a nitrate ion source in an amount, by weight of the nitrate ion, of from about 470 to about 710 grams/liter; and a bifluoride ion source in an amount, by weight of the bifluoride ion, of from about 0.5 to about 15 grams/liter.

Abstract: A method for selectively removing an aluminide coating from at least one surface of a metal-based substrate by: (a) contacting the surface of the substrate with at least one stripping composition comprising nitric acid at a temperature less than about 20° C. to degrade the coating without damaging the substrate; and (b) removing the degraded coating without damaging the substrate. Also disclosed is a method for replacing a worn or damaged aluminide coating on at least one surface of a metal-based substrate by selectively removing the coating using the above steps, and then applying a new aluminide coating to the surface of the substrate. Turbine engine parts, such as high-pressure turbine blades, treated using the above methods are also disclosed.

Abstract: A chromium oxide coating is removed from a surface of an article by cleaning the article in an alkaline degreasing/rust removal solution at a degreasing/rust removal temperature of from about 180° F. to about 200° F., scale conditioning the article in an alkaline permanganate conditioning solution at a scale-conditioning temperature of from about 160° F. to about 200° F., and contacting the article to an acidic stripping solution comprising hydrochloric acid and an etching inhibitor at a stripping temperature of from about 130° F. to about 140° F.

Abstract: A method of removing a ceramic coating (18), and particularly zirconia-containing thermal barrier coating (TBC) materials such as yttria-stabilized zirconia (YSZ), that has been either intentionally or unintentionally deposited on the surface of a component (10). The method entails subjecting the ceramic coating (18) to an aqueous solution containing an acid fluoride salt, such as ammonium bifluoride (NH4HF2) or sodium bifluoride (NaHF2), and a corrosion inhibitor. The method is capable of completely removing the ceramic coating (18) without removing or damaging the underlying substrate material, which may include a metallic bond coat (16).

Abstract: A method of removing a ceramic coating (18), and particularly zirconia-containing thermal barrier coating (TBC) materials such as yttria-stabilized zirconia (YSZ), that has been either intentionally or unintentionally deposited on the surface of a component (10). The method entails subjecting the ceramic coating (18) to an aqueous solution containing an acid fluoride salt, such as ammonium bifluoride (NH4HF2) or sodium bifluoride (NaHF2), and a corrosion inhibitor. The method is capable of completely removing the ceramic coating (18) without removing or damaging the underlying substrate material, which may include a metallic bond coat (16).