Abstract: A core-shell ceramic particulate is provided. The core-shell ceramic particulate comprises a core particulate structure comprising a plurality of primary particulates and a plurality of primary pores; and a shell at least partially enclosing the core particulate structure. Each of the primary particulates comprises a plurality of secondary particulates and a plurality of secondary pores; and the shell comprises a plurality of tertiary particulates and a plurality of tertiary pores. A method of making a core-shell ceramic particulate is provided. The method comprises the steps of providing a core particulate structure comprising a plurality of primary particulates and a plurality of primary pores wherein each primary particulate comprises a plurality of secondary particulates and a plurality of secondary pores; and disposing a shell comprising a plurality of tertiary particulates and a plurality of tertiary pores onto the core particulate structure.

Abstract: A technique for operating a sensor system is provided. The method includes exciting a first sensor with a first excitation signal at a first frequency and exciting a second sensor with a second excitation signal at a second frequency. The technique also includes combining a first measurement signal generated from the first sensor with a second measurement signal generated from the second sensor to determine a sensed parameter. The technique may be employed for reducing crosstalk between closely proximate sensors, such as capacitive probes, and may serve to determine distances within operating machines, such as turbine systems.

Abstract: A process for repairing a turbine component comprises overlaying a preform of a brazing material onto a surface of the turbine component, wherein the surface comprises a damaged portion; securing the preform of a brazing material to the surface; and heating the turbine component to a temperature effective to form a brazed joint between the brazing material and the turbine component. Also disclosed is a repaired turbine component repaired by the process.

Abstract: A method for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating (“TBC”) of the component comprises providing a photoluminescent (“PL”) material in the TBC, directing an exciting radiation at the TBC, measuring the intensity of a characteristic peak in the emission spectrum of the PL material, and correlating the intensity of the characteristic peak or another quantity derived therefrom to an amount of a new phase that has been formed as a result of the exposure of the component to extreme temperatures. An apparatus for carrying out the method comprises a radiation source that provides the exciting radiation to the TBC, a radiation detector for detecting radiation emitted by the PL material, and means for relating a characteristic of the emission spectrum of the PL material to the amount of the new phase in the TBC, thereby inferring the past-service conditions or the remaining useful life of the component.

Abstract: A beta-phase NiAl overlay coating containing a dispersion of ceramic particles and a process for depositing the overlay coating. If the coating is used to adhere a thermal barrier coating (TBC), the TBC exhibits improved spallation resistance as a result of the dispersion of ceramic particles having a dispersion-strengthening effect on the overlay coating. The overlay coating contains at least one reactive element and is deposited so that the some of the reactive element deposits as the ceramic particles dispersed in the overlay coating.

Abstract: A method for selectively removing oxide material from the surface of a substrate or coating disposed on the substrate is disclosed. The method includes the step of contacting the oxide material with an aqueous treatment composition having the formula HxAF6, wherein A can be Si, Ge, Ti, Zr, Al, and Ga; and x is 1-6. The composition can sometimes include an additional acid, such as phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, and mixtures thereof. A method for replacing a worn or damaged protective coating applied over a substrate, utilizing the treatment composition, is also described.

Abstract: A method for selectively removing one or more coatings from the surface of a substrate is described. The coating is treated with an aqueous composition which includes an acid of the formula HxAF6, or precursors to such an acid. In that formula, A is Si, Ge, Ti, Zr, Al, and Ga; and x is 1-6. The acid is often H2SiF6. The composition may sometimes include at least one additional acid, such as phosphoric acid. The coating being removed is often an aluminide coating or an MCrAl(X)-type material. The substrate is usually a polymer or a metal, such as a superalloy.

Abstract: A beta-phase NiAl overlay coating containing a dispersion of ceramic particles and a process for depositing the overlay coating. If the coating is used to adhere a thermal barrier coating (TBC), the TBC exhibits improved spallation resistance as a result of the dispersion of ceramic particles having a dispersion-strengthening effect on the overlay coating. The overlay coating contains at least one reactive element and is deposited so that the some of the reactive element deposits as the ceramic particles dispersed in the overlay coating.

Abstract: A method for preparing a solution for treating an article, a treatment solution made thereby, and a method for treating an article with the solution are presented with, for example, the treatment method comprising providing a quantity of treatment solution, the treatment solution comprising an acid having the formula HxAF6, wherein A is selected from the group consisting of Si, Ge, Ti, Zr, Al, and Ga, and x is in the range from about 1 to about 6; determining a concentration of free acid contaminant in the treatment solution; and removing the concentration of free acid contaminant.

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 determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating (“TBC”) of the component comprises providing a photoluminescent (“PL”) material in the TBC, directing an exciting radiation at the TBC, measuring the intensity of a characteristic peak in the emission spectrum of the PL material, and correlating the intensity of the characteristic peak or another quantity derived therefrom to an amount of a new phase that has been formed as a result of the exposure of the component to extreme temperatures.

Abstract: A method for selectively removing portions of a diffusion aluminide coating from a substrate is described. The coating is treated with an aqueous composition based on an acid having the formula HxZrF6, wherein x is an exemplary 2. The coating being removed is usually a noble metal-aluminide coating, and the substrate is typically a superalloy. Related compositions are also described.

Abstract: An apparatus for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating (“TBC”) of the component comprises a radiation source that provides the exciting radiation to the TBC to excite a photoluminescent (“PL”) material contained therein, a radiation detector for detecting radiation emitted by the PL material, and means for relating a characteristic of an emission spectrum of the PL material to the amount of a crystalline phase in the TBC, thereby inferring the past-service conditions or the remaining useful life of the component or the TBC.

Abstract: A on-line method is provided for detecting wear and/or damage to gas turbine parts. Preferred embodiments of the invention provide a gas turbine comprising parts with smart coatings and collection and detection means to measure wear and erosion of gas turbine parts. In other preferred embodiments, smart coatings are provided comprising chemical taggants that can be collected and detected downstream, thus providing an on-line or in situ evaluation technology for wear and damage to gas turbine parts.

Abstract: A method for preparing a solution for treating an article, a treatment solution made thereby, and a method for treating an article with the solution are presented with, for example, the treatment method comprising providing a quantity of treatment solution, the treatment solution comprising an acid having the formula HxAF6, wherein A is selected from the group consisting of Si, Ge, Ti, Zr, Al, and Ga, and x is in the range from about 1 to about 6; determining a concentration of free acid contaminant in the treatment solution; and removing the concentration of free acid contaminant.

Abstract: A fluorescent probe is applied to bind to a metal oxide on a substrate and the substrate is exposed to an ultraviolet light to identify the metal oxide. A chemical cleaning or stripping solution is selected by combinatorial high throughput screening (CHTS). In the method, an array of regions is defined on a substrate, a candidate cleaning/stripping solution is deposited onto the regions to effect cleaning/stripping of the regions; a fluorescent probe is applied to bind to a metal oxide on the substrate; the substrate is exposed to an ultraviolet light to identify the metal oxide and a product of the cleaning/stripping is evaluated according to the identified metal oxide. An activated metal substrate composition is provided that comprises a metal substrate with a contaminant metal oxide coating and a fluorescent activator bound to the substrate by reaction with the metal oxide coating.

Abstract: A liquid chemical stripping or cleaning solution is selected by combinatorial high throughput screening. A high throughput screening well array assembly includes (A) a metal substrate and (B) a mask that defines an array of wells on the substrate. A combinatorial high throughput screening system includes (A) a metal substrate and (B) a mask that defines an array of wells on the substrate and a reaction vessel to receive the well array assembly.

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 method for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating (“TBC”) of the component comprises providing a photoluminescent (“PL”) material in the TBC, directing an exciting radiation at the TBC, measuring the intensity of a characteristic peak in the emission spectrum of the PL material, and correlating the intensity of the characteristic peak or another quantity derived therefrom to an amount of a new phase that has been formed as a result of the exposure of the component to extreme temperatures.

Abstract: A on-line method is provided for detecting wear and/or damage to gas turbine parts. Preferred embodiments of the invention provide a gas turbine comprising parts with smart coatings and collection and detection means to measure wear and erosion of gas turbine parts. In other preferred embodiments, smart coatings are provided comprising chemical taggants that can be collected and detected downstream, thus providing an on-line or in situ evaluation technology for wear and damage to gas turbine parts.