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: Calcium magnesium aluminosilicate (CMAS) mitigation compositions selected from rare earth elements, rare earth oxides, zirconia, hafnia partially or fully stabilized with alkaline earth or rare earth elements, zirconia partially or fully stabilized with alkaline earth or rare earth elements, magnesium oxide, cordierite, aluminum phosphate, magnesium silicate, and combinations thereof when the CMAS mitigation composition is included as a separate CMAS mitigation layer in an environmental barrier coating for a high temperature substrate component.

Abstract: Methods of making components having calcium magnesium aluminosilicate (CMAS) mitigation capability involving providing a component; applying an environmental barrier coating to the component, the environmental barrier coating having a separate CMAS mitigation layer including a CMAS mitigation composition selected from rare earth elements, rare earth oxides, zirconia, hafnia partially or fully stabilized with alkaline earth or rare earth elements, zirconia partially or fully stabilized with alkaline earth or rare earth elements, magnesium oxide, cordierite, aluminum phosphate, magnesium silicate, and combinations thereof.

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: Turbine airfoil components with protective layers and methods therefore. The components are each formed to have a platform, an airfoil extending upwardly from the platform, and a shank extending downwardly from the platform. The shank has an exterior wall and an internal passage, and the airfoil has a cooling flow channel inside the airfoil for flowing a cooling flow therethrough. The component has an interior chromide coating contacting at least a portion of an interior surface of the shank and interdiffused with a base metal thereof, and an exterior chromide coating contacting at least a portion of an exterior surface of the shank and interdiffused with the base metal thereof. The interior and exterior chromide coatings do not have an aluminide coating deposited thereon.

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 process by which a nickel-based superalloy substrate prone to deleterious reactions with an aluminum-rich coating can be stabilized by carburization. The process generally entails processing the surface of the substrate to be substantially free of oxides, heating the substrate in a non-oxidizing atmosphere to a carburization temperature, and then contacting the surface of the substrate with a carburization gas mixture comprising a diluted low activity hydrocarbon gas while maintaining the substrate at the carburization temperature. While at the carburization temperature and contacted by the carburization gas, carbon atoms in the carburization gas dissociate therefrom, transfer onto the surface of the substrate, diffuse into the substrate, and react with refractory metals within the substrate to form refractory metal carbides within a carburized region beneath the surface of the substrate. The substrate is then cooled in a non-oxidizing atmosphere to terminate carbide formation.

Abstract: A coating process for an article having a substrate formed of a metal alloy that is prone to the formation of a secondary reaction zone (SRZ). The coating process forms a coating system that includes an aluminum-containing overlay coating and a stabilizing layer between the overlay coating and the substrate. The overlay coating contains aluminum in an amount greater by atomic percent than the metal alloy of the substrate, such that there is a tendency for aluminum to diffuse from the overlay coating into the substrate. The stabilizing layer is predominantly or entirely formed of at least one platinum group metal (PGM), namely, platinum, rhodium, iridium, and/or palladium. The stabilizing layer is sufficient to inhibit diffusion of aluminum from the overlay coating into the substrate so that the substrate remains essentially free of an SRZ that would be deleterious to the mechanical properties of the alloy.

Abstract: Gas turbine engine compressor disks having a hot flowpath side; a shaft having a first surface positioned in the hot flowpath side; and a thermal barrier applied to at least the first surface of the shaft where the thermal barrier is operable to maintain the temperature of the shaft below about 700° C. (1300° F.) when the hot flowpath side experiences a service operating temperature of from about 700° C. (1300° F.) to about 788° C. (1450° F.).

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: A protective coating for use on a silicon-containing substrate, and deposition methods therefor. The coating has a strontium-aluminosilicate (SAS) composition that is less susceptible to degradation by volatilization and in corrosive environments as a result of having at least an outer surface region that consists essentially of one or more stoichiometric crystalline phases of SAS and is substantially free of a nonstoichiometric second crystalline phase of SAS that contains a substoichiometric amount of silica. The coating can be produced by carrying out deposition and heat treatment steps that result in the entire coating or just the outer surface region of the coating consisting essentially of the stoichiometric celsian phase.

Abstract: Method comprising providing a coating precursor composition including a corrosion resistant particulate component having an average coefficient of thermal expansion (CTE) greater than alumina at 1200° F. (649° C.) dispersed in a binder matrix, wherein an aspect ratio of at least a portion of the corrosion resistant particulate component is greater than about 2:1, and wherein the binder matrix includes at least one member of the group consisting of a silicon-containing material and a phosphate-containing material; providing the coating precursor composition on at least a portion of a metal substrate, and; curing the coating precursor composition to provide a corrosion-resistant coating on at least the portion of the metal substrate.

Abstract: A coated article suitable for use at elevated temperature includes a metal substrate and a coating on the substrate. The coating includes a corrosion resistant particulate component having an average coefficient of thermal expansion (CTE) greater than alumina at 1200° F. (649° C.) dispersed in a binder matrix. An aspect ratio of at least a portion of the corrosion resistant particulate component is greater than about 2:1. The binder matrix includes a silicon-containing material and/or a phosphate-containing material.

Abstract: A method for producing a thermal barrier coating/environmental barrier coating system on a silicon containing material substrate includes applying an environmental barrier coating (EBC) over the silicon containing material substrate; and applying a thermal barrier coating (TBC) over the EBC. The thermal barrier coating includes a compound having a primary constituent portion and a stabilizer portion stabilizing said primary constituent. The primary constituent portion of the thermal barrier coating includes hafnia present in an amount of at least about 5 mol % of the primary constituent and the stabilizer portion of said thermal barrier coating includes at least one metal oxide comprised of cations with a +2 or +3 valence present in the amount of about 10 to about 40 mol % of the thermal barrier coating.

Abstract: A superalloy composition comprising, in weight percent: about 6.2-6.6 Al, about 6.5-7.0 Ta, about 6.0-7.0 Cr, about 6.25-7.0 W, about 1.5-2.5 Mo, about 0.15-0.60 Hf, 0.0-1.0 Re, 6.5-9.0 Co, optionally, 0.03-0.06 C, optionally, up to about 0.004 B, optionally up to about 0.03 total of one or more rare earth elements selected from yttrium (Y), lanthanum (La), or cerium (Ce), balance nickel, such that the superalloy composition exhibits a stress rupture capability improvement of at least 15% over a base stress rupture capability of a base composition nominally comprising, in weight percent: 6.5 Al, 6.6 Ta, 6.0 Cr, 6.25 W, 1.5 Mo, 0.15 Hf, 0.0 Re, 7.5 Co. Articles incorporating the superalloy composition include a gas turbine engine component such as a high pressure turbine nozzle or nozzle segment.

Abstract: A ductile corrosion and oxidation resistant coating, being predominately of gamma-prime nickel aluminide intermetallic includes 15-30 atomic % aluminum, up to atomic % chromium, optionally, up to 30 atomic % of a platinum group metal, optionally, up to 4 atomic % of a reactive element, and optionally, up to 15 atomic % of at least one strengthening element, and a balance being essentially nickel or nickel and at least one of cobalt, iron, or cobalt and iron. A coated article includes the ductile corrosion and oxidation resistant coating on a superalloy substrate such as a turbine disk, turbine seal, a turbine blade, a turbine nozzle, a turbine shroud, or a turbine frame or case having an under platform or non-gas path region.

Abstract: Method includes providing a superalloy substrate such as a turbine disk, a turbine seal, a turbine blade, a turbine nozzle, a turbine shroud, or a turbine frame or case having an under platform or non-gas path region; and providing a predominantly gamma-prime nickel aluminide intermetallic ductile corrosion and oxidation resistant coating disposed on at least a portion of the substrate. The coating comprises from about 15 to about 30 atomic % aluminum, up to about 20 atomic % chromium, optionally, up to about 30 atomic % of at least one platinum group metal, optionally, up to about 4 atomic % of at least one reactive element, and optionally, up to about 15 atomic % of at least one strengthening element, and a balance being essentially nickel or nickel and at least one of cobalt, iron, or cobalt and iron. A coating precursor composition may be applied to the substrate before or after optional plating with one or more platinum group metals.

Abstract: A process by which a nickel-based superalloy substrate prone to deleterious reactions with an aluminum-rich coating can be stabilized by carburization. The process generally entails processing the surface of the substrate to be substantially free of oxides, heating the substrate in a non-oxidizing atmosphere to a carburization temperature, and then contacting the surface of the substrate with a carburization gas mixture comprising a diluted low activity hydrocarbon gas while maintaining the substrate at the carburization temperature. While at the carburization temperature and contacted by the carburization gas, carbon atoms in the carburization gas dissociate therefrom, transfer onto the surface of the substrate, diffuse into the substrate, and react with refractory metals within the substrate to form refractory metal carbides within a carburized region beneath the surface of the substrate. The substrate is then cooled in a non-oxidizing atmosphere to terminate carbide formation.

Abstract: A coating system and a method for forming the coating system, the method including coating a surface of a gas turbine engine turbine component having a metallic surface that is outside the combustion gas stream and exposed to cooling air during operation of the engine. A gel-forming solution including a ceramic metal oxide precursor is provided. The gel-forming solution is heated to a first preselected temperature for a first preselected time to form a gel. The gel is then deposited on the metallic surface. Thereafter the gel is fired at a second preselected temperature above the first preselected temperature to form a ceramic corrosion resistant coating comprising a ceramic metal oxide is selected from the group consisting of zirconia, hafnia and combinations thereof. The ceramic corrosion resistant coating having a thickness of up to about 127 microns and remaining adherent at temperatures greater than about 1000° F.