摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.