Abstract: The disclosure relates generally to recovering bond coat materials and barrier coat materials from co-mingled mixtures of bond coat and barrier coat materials (e.g., plasma overspray waste), and from mixtures of co-mingled bond coat and barrier coat materials stripped from a substrate. The disclosure also relates to recovering rare earth elements (e.g., yttrium) from a barrier coat of the co-mingled plasma overspray waste or mixture of co-mingled bond coat and barrier coat materials stripped from the substrate.

Abstract: The disclosure relates generally to recovering bond coat materials and barrier coat materials from co-mingled mixtures of bond coat and barrier coat materials (e.g., plasma overspray waste), and from mixtures of co-mingled bond coat and barrier coat materials stripped from a substrate. The disclosure also relates to recovering rare earth elements (e.g., yttrium) from a barrier coat of the co-mingled plasma overspray waste or mixture of co-mingled bond coat and barrier coat materials stripped from the substrate.

Abstract: An aluminizing composition includes an aluminum-based powder, an inert organic pyrolysable thickener, and a binder selected from the group consisting of colloidal silica, at least one organic resin, and combinations thereof. A method for aluminizing an internal passage of a metal substrate comprises injecting the organic-based aluminizing composition into the internal passage, heat treating the composition under conditions sufficient to remove volatile components from the composition, to cause diffusion of aluminum into surface regions of the internal passage, and to cause decomposition of at least some pyrolysable thickener particles, and burnishing excess material from the internal passage.

Abstract: A slurry coating composition is described, which is very useful for enriching the surface region of a metal-based substrate with aluminum. The composition includes colloidal silica and particles of an aluminum-based powder, and is substantially free of hexavalent chromium. The slurry may include colloidal silica and an alloy of aluminum and silicon. Alternatively, the slurry includes colloidal silica, aluminum or aluminum-silicon, and an organic stabilizer such as glycerol. The slurry exhibits good thermal and chemical stability for extended periods of time, making it very useful for industrial applications. Related methods and articles are also described.

Abstract: A method for storing hydrogen is described. The hydrogen is infused into hollow spheres. The spheres are made from a polymer which has a tensile strength sufficient to contain hydrogen under selected internal pressure conditions; and has a permeation coefficient which can be adjusted under variable humidity conditions. Adjustment of the humidity level after the hydrogen is infused results in the walls of the spheres becoming impermeable to hydrogen. The hydrogen stored in the spheres can then be released at a desired time by readjusting the humidity level. The released hydrogen can be directed to any type of equipment which is fueled by hydrogen or otherwise uses the gas. Related articles and systems are also described.

Abstract: A process for chemically stripping a metallic coating on an external surface of a substrate without attacking an internal surface defined by an internal passage within the substrate. Processing steps include depositing within the internal passage a thermally-decomposable wax having a melting temperature above 75° C. so as to mask the internal surface of the substrate, and then treating the substrate with an aqueous solution containing an acid having the formula HxAF6 where A is silicon, germanium, titanium, zirconium, aluminum, or gallium, and x has a value of one to six. The aqueous solution is at a temperature below the melting temperature of the wax and substantially removes the metallic coating from the external surface of the substrate, while the wax is substantially unreactive with the aqueous solution and prevents the aqueous solution from contacting the internal surface of the substrate. Thereafter, the substrate is heated to thermally decompose the wax without producing hazardous byproducts.

Abstract: Disclosed herein is a multifunctional catalyst system comprising a substrate; and a catalyst pair disposed upon the substrate; wherein the catalyst pair comprises a first catalyst and a second catalyst; and wherein an average particle or domain spacing between particles or domains comprising the first catalyst or the second catalyst is about 10 to about 1,000 nanometers. Disclosed herein too is a process comprising selectively functionalizing a substrate to form a functionalized substrate; reacting a first catalyst to a first region of the functionalized substrate; and reacting a second catalyst to a second region of the functionalized substrate; wherein an average particle or domain spacing between particles or domains comprising the first catalyst or the second catalyst is about 10 to about 1,000 nanometers.

Abstract: Disclosed herein is a multifunctional catalyst system comprising a substrate; and a catalyst pair disposed upon the substrate; wherein the catalyst pair comprises a first catalyst and a second catalyst; and wherein the first catalyst initiates or facilitates the reduction of carbon dioxide to carbon monoxide while the second catalyst initiates or facilitates the conversion of carbon monoxide to an organic compound. Disclosed herein is a method comprising reducing carbon dioxide to carbon monoxide in a first reaction catalyzed by a first catalyst; and reacting carbon monoxide with hydrogen in a second reaction catalyzed by second catalyst; wherein the first catalyst and the second catalyst are disposed upon a single substrate.

Abstract: A corrosion resistant coating for engine components such as turbine disks, turbine seal elements and turbine shafts. This coating may also find application to other turbine components that are subjected to high temperatures and corrosive environments, such as turbine components located within or on the boundary of the gas fluid flow path, including for example turbine blades, turbine vanes, liners and exhaust flaps. The corrosion resistant coating of the present invention in service on a gas turbine component includes a glassy ceramic matrix wherein the glassy matrix is silica-based and particles selected from the group consisting of refractory oxide particles, MCrAlX particles and combinations of these particles, substantially uniformly distributed within the matrix. The refractory oxide and/or the MCrAlX provides the coating with corrosion resistance. Importantly the coating of the present invention has a coefficient of thermal expansion (CTE) greater than alumina.

Abstract: An aluminizing composition includes an aluminum-based powder, an inert organic pyrolysable thickener, and a binder selected from the group consisting of colloidal silica, at least one organic resin, and combinations thereof. A method for aluminizing an internal passage of a metal substrate comprises injecting the organic-based aluminizing composition into the internal passage, heat treating the composition under conditions sufficient to remove volatile components from the composition, to cause diffusion of aluminum into surface regions of the internal passage, and to cause decomposition of at least some pyrolysable thickener particles, and burnishing excess material from the internal passage.

Abstract: A porous structure and method of making the porous structure is disclosed. The porous structure includes a substrate comprising at least one pore having an internal surface. At least a first portion of the internal surface of the at least one pore has a first fluid contact angle and at least second portion of the internal surface of the at least one pore has a second fluid contact angle. The difference between the first fluid contact angle and the second fluid contact angle has an absolute value of at least about 5 degrees and the second fluid contact angle is greater than about 40 degrees.

Abstract: An aqueous composition for the chemical removal of metallic surfacing present on the blades of turbines, preferably gas turbines, comprises at least hexafluorosilicic acid and phosphoric acid.

Abstract: A chemical composition for selectively removing an aluminum-containing material from a substrate comprises an acid having a formula of HxAF6, a precursor thereof, and a mixture of said acid and said precursor; wherein A is selected from the group consisting of Si, Ge, Ti, Zr, Al, and Ga; and x is in a range from 1 to 6, inclusive. The chemical composition can comprise at least another acid selected from the group consisting of phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydriodic acid, acetic acid, perchloric acid, phosphorous acid, phosphinic acid, alkyl sulfonic acids, mixtures thereof, and precursors thereof. The chemical composition can be used to remove aluminum seal strips selectively from the dovetail of a turbine-engine blade.

Abstract: A method for removing an oxide material from a crack in a substrate, the method includes: applying a slurry paste comprising a fluoride salt to the crack; heating the slurry paste and the crack to at least a melting point of the fluoride salt to form a reaction product; and removing the reaction product.

Abstract: A method for removing a chromide coating from the surface of a substrate is described. The coating is treated with a composition which includes an acid having the formula HxAF6, where “A” can be Si, Ge, Ti, Zr, Al, or Ga; and x is 1-6. An exemplary acid is hexafluorosilicic acid. The composition may also include a second acid, such as phosphoric acid or nitric acid. In some instances, a third acid is employed, such as hydrochloric acid. A related repair method for replacing a worn or damaged chromide coating is described. The coating is often applied to portions of turbine engine components made from superalloy materials.

Abstract: A slurry coating composition is described, which is very useful for enriching the surface region of a metal-based substrate with aluminum. The composition includes colloidal silica and particles of an aluminum-based powder, and is substantially free of hexavalent chromium. The slurry may include colloidal silica and an alloy of aluminum and silicon. Alternatively, the slurry includes colloidal silica, aluminum or aluminum-silicon, and an organic stabilizer such as glycerol. The slurry exhibits good thermal and chemical stability for extended periods of time, making it very useful for industrial applications. Related methods and articles are also described.

Abstract: An organic coating composition is described, which can be used to enrich the surface region of a metal-based substrate with aluminum. The composition comprises an aluminum-based powder and at least one organic resin, e.g., alkyds, epoxies, or silicone materials. At least some of the aluminum-based powder is in the form of substantially spherical powder particles. The coating composition is substantially free of hexavalent chromium. It can be applied to the substrate by a variety of techniques, such as spraying. It is then heat-treated, to cause diffusion of aluminum into the surface region of the substrate, e.g., a turbine engine component. The composition exhibits good thermal and chemical stability for extended periods of time. Related articles are also described.

Abstract: Non-destructive systems and methods for temperature measurements are described so that the remaining operational life and accumulated damage of high temperature gas turbine components can be assessed. Alloy-based witness coupons and diffusion couple witness coupons are attached to, or directly applied onto, high temperature components so that they experience the same high temperature operation and shut down as the components themselves. The witness coupons are later removed from the components and analyzed, or are analyzed on the component, to determine the change to their microstructure, metallurgy, and/or diffusion characteristics. Since the time each component spends in operation is known, the operating temperatures of the components can be back-calculated from the microstructural, metallurgical, and/or diffusion characteristic changes of the witness coupons. Therefrom, the remaining operational life of the component can be assessed, as can the accumulated damage to the component.