Abstract: A fluoride ion cleaning method includes generating hydrogen fluoride (HF) gas in-situ in a cleaning retort; contacting a part in need of cleaning with the generated HF gas; scrubbing an initial effluent stream in-situ to substantially remove residual HF gas therefrom; and passing the scrubbed effluent gas stream out of the cleaning retort. In an exemplary method, a liquid or gaseous halogenated feedstock is introduced into a cleaning retort; hydrogen gas is introduced into the cleaning retort, HF gas is generated by a reaction of the feedstock with hydrogen gas at a sufficient temperature. In an exemplary method, only HF gas generated in-situ or reconstituted in-situ is utilized in the cleaning process.

Abstract: A fluoride ion cleaning method includes generating hydrogen fluoride (HF) gas in-situ in a cleaning retort; contacting a part in need of cleaning with the generated HF gas; scrubbing an initial effluent stream in-situ to substantially remove residual HF gas therefrom; and passing the scrubbed effluent gas stream out of the cleaning retort. In an exemplary method, a liquid or gaseous halogenated feedstock is introduced into a cleaning retort; hydrogen gas is introduced into the cleaning retort, HF gas is generated by a reaction of the feedstock with hydrogen gas at a sufficient temperature. In an exemplary method, only HF gas generated in-situ or reconstituted in-situ is utilized in the cleaning process.

Abstract: System and apparatuses for utilizing in-situ generated hydrogen fluoride (HF) in a cleaning process. An exemplary system includes a cleaning retort operable at a temperature sufficient to promote an in-situ reaction between a liquid or gaseous halogenated feedstock and hydrogen gas to form the HF. The system includes a liquid or gaseous halogenated feedstock source and a hydrogen gas source disposed outside the cleaning retort which, upon reaction generate the HF within the cleaning retort. A HF scrubber, disposed within the cleaning retort, is operable to substantially remove residual HF gas formed by the in-situ reaction. An exemplary apparatus includes a cleaning retort having a first region able to hold parts in need of cleaning and a second region operable as a HF scrubber.

Abstract: Apparatus and method to improve vapor phase diffusion coating of articles. The apparatus provides a barrier to segregate the portion of the article requiring coating from the portion of the article not requiring coating. The fixture is reusable, being unaffected by the coating gases. The fixture reduces the exposure of the coating gases with the portion of the article not requiring coating. By use of an optional seal, the portion of the article not requiring coating can be isolated from the coating gases.

Abstract: A thermal barrier coating (TBC) system and method for forming the TBC system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The TBC system exhibits improved spallation resistance as a result of having a bond coat formed to contain a dispersion of oxide particles in its outer surface region. A method for preferentially entrapping oxide particles in a bond coat entails depositing the oxide particles on the surface of the component prior to forming the bond coat, which may be a diffusion aluminide or an aluminized overlay coating. Deposition of the bond coat causes the oxide particles to become dispersed in the outer surface region of the bond coat. A particular feature of this invention is the ability to preferentially entrap oxides of elements that are not present in the bond coat or a substrate region of the component on which the bond coat is formed.

Abstract: A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The coating system includes a diffusion aluminide bond coat whose oxide growth rate is significantly reduced to improve the spallation resistance of a thermal barrier layer by forming the bond coat to include a dispersion of aluminum, chromium, nickel, cobalt and/or platinum group metal oxides. The oxides preferably constitute about 5 to about 20 volume percent of the bond coat. A preferred method of forming the bond coat is to initiate a diffusion aluminizing process in the absence of oxygen to deposit a base layer of diffusion aluminide, and then intermittently introduce an oxygen-containing gas into the diffusion aluminizing process to form within the bond coat the desired dispersion of oxides.

Abstract: A process for forming a diffusion aluminide coating on a substrate, such as a component for a gas turbine engine. The process generally entails placing the substrate in a suitable coating chamber, flowing an inert or reducing gas into and through the coating chamber, and then aluminizing the substrate using an aluminizing technique with a substantially constant aluminum activity, such as a vapor phase deposition process. During the aluminizing process, the amount of unreacted aluminum within the coating chamber is controlled by altering the flow rate of the gas through the coating chamber so that a portion of the unreacted aluminum is swept from the coating chamber by the gas. The amount of unreacted aluminum swept from the coating chamber is regulated by metering the gas flow rate in order to control the aluminizing rate and aluminum content of the resulting aluminide coating.

Abstract: A process for forming a diffusion aluminide-hafnide coating on an article, such as a component for a gas turbine engine. The process is a vapor phase process that generally entails placing the article in a coating chamber containing a halide activator and at least one donor material. The donor material collectively consists essentially of at least 0.5 weight percent hafnium and at least 20 weight percent aluminum with the balance being chromium and/or cobalt.

Abstract: A process for forming a diffusion aluminide coating on an article, such as a component for a gas turbine engine. The process is a vapor phase process that generally entails placing the article in a coating chamber containing an aluminum donor material, without any halide carrier or inert filler present. The aluminum donor material consists essentially of about 20 to about 70 weight percent aluminum, with the balance being chromium or cobalt. While the article is held out of contact with the donor material, coating is initiated in an inert or reducing atmosphere by heating the article and the donor material to vaporize the aluminum constituent of the donor material, which then condenses on the surface of the article and diffuses into the surface to form a diffusion aluminide coating on the article.

Abstract: A process for reclaiming aluminum alloy donor from a vapor phase deposition process used to form a diffusion aluminide coating on a component, such as the high-temperature superalloy components of gas turbine engines. The process generally entails recycling a particulate aluminum alloy donor material that, as a result of having been used as the donor material for depositing a diffusion aluminide coating on an article by vapor phase deposition, particles of the donor material comprise an aluminum alloy core encased in an aluminum-depleted shell. The process generally entails tumbling the donor material in a manner that removes the aluminum-depleted shell, followed by sieving the donor material to remove shell fragments and undersized particles.

Abstract: A curved component such as a turbine airfoil, shroud, or combustor centerbody is prepared with a platinum or a platinum-aluminide protective coating over only a portion of the surface thereof. The coating may serve as an environmental coating, or as a bond coat of a thermal barrier coating system. The partial coverage is achieved by depositing platinum only over a portion of the surface of the component, typically including the concave portion in the case of an airfoil, optionally depositing an aluminum layer, and optionally interdiffusing the platinum and aluminum layers.

Abstract: Apparatus and method to improve vapor phase diffusion coating of articles. The apparatus provides a barrier to segregate the portion of the article requiring coating from the portion of the article not requiring coating. The fixture is reusable, being unaffected by the coating gases. The fixture reduces the exposure of the coating gases with the portion of the article not requiring coating. By use of an optional seal, the portion of the article not requiring coating can be isolated from the coating gases.

Abstract: A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The coating system includes a diffusion aluminide bond coat whose oxide growth rate is significantly reduced to improve the spallation resistance of a thermal barrier layer by forming the bond coat to include a dispersion of aluminum, chromium, nickel, cobalt and/or platinum group metal oxides. The oxides preferably constitute about 5 to about 20 volume percent of the bond coat. A preferred method of forming the bond coat is to initiate a diffusion aluminizing process in the absence of oxygen to deposit a base layer of diffusion aluminide, and then intermittently introduce an oxygen-containing gas into the diffusion aluminizing process to form within the bond coat the desired dispersion of oxides.

Abstract: A high temperature vapor coating container, including a hollow interior, resists distortion and cracking at a vapor coating temperature of at least about 1700.degree. F. as a result of making the container of a nonmetallic material having a coefficient of thermal expansion of less than about 4.5.times.10.sup.-6 at the vapor coating temperature, the material being nonreactive with the coating vapor at the vapor coating temperature.

Abstract: A thermal barrier coating system and a method for forming the coating system on an article designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The method is particularly directed to a coating system comprising an APS bond coat on which a thermal-insulating APS ceramic layer is deposited, wherein the oxidation resistance of the bond coat and the spallation resistance of the ceramic layer are increased by diffusing platinum, palladium, hafnium, rhenium and/or rhodium into the bond coat. The diffusion process is performed so as not to alter the surface roughness of the bond coat, which is maintained in a range of about 200 to about 500.mu. inch Ra.

Abstract: A thermal barrier coating system and a method for forming the coating system on an article designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The method is particularly directed to a coating system comprising an APS bond coat on which a thermal-insulating APS ceramic layer is deposited, wherein the oxidation resistance of the bond coat and the spallation resistance of the ceramic layer are increased by diffusing platinum, palladium, hafnium, rhenium and/or rhodium into the bond coat. The diffusion process is performed so as not to alter the surface roughness of the bond coat, which is maintained in a range of about 200 to about 500 .mu.inch Ra.

Abstract: An abrasive particle, for use in a manufacturing method in which the particle is exposed to a high energy beam, such as a laser, is provided with an abrasive core having an enclosing coating which protects the core from detrimental deterioration during exposure to the beam. In one form, the coating is multilayer.The particle is included on a surface of a member of a rotary seal for abrading an opposing surface.

Abstract: A method for making an engine component with a hollow interior includes the steps of: selectively patterning a principal substrate surface; forming a slurry including a selected amount of a binder material, a selected amount of a solvent and a selected amount of a filter material; inserting the slurry into the substrate surface pattern; evaporating the solvent to solidify the slurry; depositing a close-out layer of material over the patterned substrate surface and over the solidifed slurry; and without removing the close-out layer, removing the solidified slurry to provide a structure with a hollow interior.