Abstract: Systems and methods for automatic detection of defects in a coating of a component are provided. In one aspect, a coating inspection system is provided. The coating inspection system includes a heating element operable to impart heat to the component as it traverses relative thereto. An imaging device of the system captures images of the component as the heating element traverses relative to the component and applies heat thereto. The images indicate the transient thermal response of the component. The system can generate a single observation image using the captured images. The system can detect and analyze defects using the generated single observation image.

Abstract: Systems and methods for automatic detection of defects in a coating of a component are provided. In one aspect, a coating inspection system is provided. The coating inspection system includes a heating element operable to impart heat to the component as it traverses relative thereto. An imaging device of the system captures images of the component as the heating element traverses relative to the component and applies heat thereto. The images indicate the transient thermal response of the component. The system can generate a single observation image using the captured images. The system can detect and analyze defects using the generated single observation image.

Abstract: Slurry coating composition for selectively enriching surface regions of a metal-based substrate, for example, the under-platform regions of a turbine blade, with chromium. The slurry coating composition contains metallic chromium, optionally metallic aluminum in a lesser amount by weight than chromium, and optionally other constituents. The composition further includes colloidal silica, and may also include one or more additional constituents, though in any event the composition is substantially free of hexavalent chromium and sources thereof. The coating composition can be used in a process that entails applying the coating composition to a surface region to form a slurry coating, and then heating the coating to remove any volatile components of the coating composition and thereafter cause diffusion of chromium from the coating into the surface region to form a chromium-rich diffusion coating.

Abstract: A method for forming a nickel aluminide based coating on a metallic substrate includes providing a first source for providing a significant portion of the aluminum content for a coating precursor and a separate nickel alloy source for providing substantially all the nickel and additional alloying elements for the coating precursor. Cathodic arc (ion plasma) deposition techniques may be utilized to provide the coating precursor on a metallic substrate. The coating precursor may be provided in discrete layers, or from a co-deposition process. Subsequent processing or heat treatment forms the nickel aluminide based coating from the coating precursor.

Abstract: Slurry coating composition for selectively enriching surface regions of a metal-based substrate, for example, the under-platform regions of a turbine blade, with chromium. The slurry coating composition contains metallic chromium, optionally metallic aluminum in a lesser amount by weight than chromium, and optionally other constituents. The composition further includes colloidal silica, and may also include one or more additional constituents, though in any event the composition is substantially free of hexavalent chromium and sources thereof. The coating composition can be used in a process that entails applying the coating composition to a surface region to form a slurry coating, and then heating the coating to remove any volatile components of the coating composition and thereafter cause diffusion of chromium from the coating into the surface region to form a chromium-rich diffusion coating.

Abstract: A method for selectively removing an aluminum-poor overlay coating from a substrate of a component, which as a result of its low aluminum content is highly resistant to a selective stripping solution. The method entails diffusing aluminum into the overlay coating to form an aluminum-infused overlay coating having an increased aluminum level in at least an outer surface thereof. The diffusion step is carried out so that the increased aluminum level is sufficient to render the aluminum-infused overlay coating removable by selective stripping. The outer surface of the aluminum-infused overlay coating is then contacted with an aqueous composition to remove the aluminum-infused overlay coating from the substrate. The aqueous composition includes at least one acid having the formula HxAF6, and/or precursors thereof, wherein A is Si, Ge, Ti, Zr, Al, and/or Ga, and x is from 1 to 6.

Abstract: A turbine blade having an internal skeleton having a plurality of internal ribs that form a plurality of open cooling channels; an internal environmental coating applied to the internal skeleton; an outer wall applied about the open cooling channels of the internal skeleton to form a near wall circuit of cooling channels; and an external environmental coating applied to the outer wall wherein the internal environmental coating is different from the external environmental coating.

Abstract: Methods for making a turbine blade involving casting an internal skeleton having a plurality of internal ribs which form a plurality of open cooling channels, applying a filler material to the open cooling channels, and applying an outer wall about the internal skeleton having the filler material applied to the open cooling channels.

Abstract: A method for forming a nickel aluminide based coating on a metallic substrate includes providing a first source for providing a significant portion of the aluminum content for a coating precursor and a separate nickel alloy source for providing substantially all the nickel and additional alloying elements for the coating precursor. Cathodic arc (ion plasma) deposition techniques may be utilized to provide the coating precursor on a metallic substrate. The coating precursor may be provided in discrete layers, or from a co-deposition process. Subsequent processing or heat treatment forms the nickel aluminide based coating from the coating precursor.

Abstract: A method for forming a nickel aluminide based coating on a metallic substrate includes providing a first source for providing a significant portion of the aluminum content for a coating precursor and a separate nickel alloy source for providing substantially all the nickel and additional alloying elements for the coating precursor. Cathodic arc (ion plasma) deposition techniques may be utilized to provide the coating precursor on a metallic substrate. The coating precursor may be provided in discrete layers, or from a co-deposition process. Subsequent processing or heat treatment forms the nickel aluminide based coating from the coating precursor.

Abstract: Disclosed herein is a method for aluminiding an internal passage of a metal substrate comprising injecting a slurry composition that comprises a powder comprising aluminum, a binder selected from the group consisting of colloidal silica, an organic resin, and a combination thereof, into the internal passage; applying compressed air to the internal passage to facilitate distribution of the slurry composition throughout the internal passage; and, heat treating the slurry composition under conditions sufficient to remove volatile components from the composition, and to cause diffusion of aluminum into a surface of the internal passage.

Abstract: A method for applying a seal strip to a surface of a turbine component by accelerating solid particles to a velocity sufficient to cause the solid particles to plastically deform and bond to the surface and each other when impacted on the surface, and impacting the solid particles on the surface so as to cause the solid particles to deform and bond to the surface and each other to form the seal strip on the surface.

Abstract: A method for depositing a platinum-group-containing layer on a substrate includes furnishing the substrate, and preparing a water-base paint containing metallic platinum-group powder, water, and a binder. The method further includes spraying the water-base paint overlying the substrate to form a platinum-group-containing layer, and thereafter heating the platinum-group-containing layer to interdiffuse the platinum-group-containing layer.

Abstract: Slurry coating process for selectively enriching surface regions of a metal-based substrate, for example, the under-platform regions of a turbine blade, with chromium. The process employs a slurry coating composition containing metallic chromium, optionally metallic aluminum in a lesser amount by weight than chromium, and optionally other constituents. The composition further includes colloidal silica, and may also include one or more additional constituents, though in any event the composition is substantially free of hexavalent chromium and sources thereof. The coating composition is applied to a surface region to form a slurry coating, which is then heated to remove any volatile components of the coating composition and thereafter cause diffusion of chromium from the coating into the surface region to form a chromium-rich diffusion coating.

Abstract: A method for selectively removing an aluminum-poor overlay coating from a substrate of a component, which as a result of its low aluminum content is highly resistant to a selective stripping solution. The method entails diffusing aluminum into the overlay coating to form an aluminum-infused overlay coating having an increased aluminum level in at least an outer surface thereof. The diffusion step is carried out so that the increased aluminum level is sufficient to render the aluminum-infused overlay coating removable by selective stripping. The outer surface of the aluminum-infused overlay coating is then contacted with an aqueous composition to remove the aluminum-infused overlay coating from the substrate. The aqueous composition includes at least one acid having the formula HxAF6, and/or precursors thereof, wherein A is Si, Ge, Ti, Zr, Al, and/or Ga, and x is from 1 to 6.

Abstract: Disclosed is a method for selectively removing a coating from a substrate. Aluminum is diffused into the coating. The coating is contacted with an aqueous composition including at least one of an acid having the formula HxAF6, and precursors to the acid, A being selected from the group consisting of Si, Ge, Ti, Zr, Al, and Ga, and x being 1-6. The coating being removed is often an McrAl(X) material. The substrate is a metal, usually a superalloy.

Abstract: A method for depositing a platinum-group-containing layer on a substrate includes furnishing the substrate, and preparing a water-base paint containing metallic platinum-group powder, water, and a binder. The method further includes spraying the water-base paint overlying the substrate to form a platinum-group-containing layer, and thereafter heating the platinum-group-containing layer to interdiffuse the platinum-group-containing layer.

Abstract: Disclosed herein is a method for aluminiding an internal passage of a metal substrate comprising injecting a slurry composition that comprises a powder comprising aluminum, a binder selected from the group consisting of colloidal silica, an organic resin, and a combination thereof, into the internal passage; applying compressed air to the internal passage to facilitate distribution of the slurry composition throughout the internal passage; and, heat treating the slurry composition under conditions sufficient to remove volatile components from the composition, and to cause diffusion of aluminum into a surface of the internal passage.

Abstract: A nickel-base braze material suitable for closing holes in a high temperature component, such as a tip cap hole in a turbine blade. The braze material comprises first and second filler materials and a binder. The first filler material comprises particles of a first alloy, and the second filler material comprises particles of at least a second alloy having a lower melting temperature than the first alloy. The second alloy consists essentially of, by weight, about 8 to about 23 percent chromium, about 4 to about 18 percent cobalt, about 1.5 to about 6.0 percent tantalum, about 1.0 to about 6.0 percent aluminum, about 0.3 to about 1.5 percent boron, about 2.0 to about 6.0 percent silicon, up to 0.2 percent carbon, the balance being nickel and incidental impurities.