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.

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 nickel-base superalloy composition including (measured in % by weight) from about 6.5 to about 7.5% aluminum, from about 4 to about 8% tantalum, from about 3 to about 10% chromium, from about 2 to about 7% tungsten, from 0 to about 4% molybdenum, from 0 to about 6% rhenium, from 0 to less than about 0.001% niobium, from 0 to about 5% cobalt, from 0 to about 0.2% silicon, from 0 to about 0.06% carbon, optionally, from 0 to about 0.5% titanium, from 0 to about 0.005% boron, from about 0.15 to about 0.7% hafnium, from 0 to about 0.03% of a rare earth addition selected from the group consisting of yttrium, lanthanum, cesium, and combinations thereof, balance nickel and incidental impurities. The nickel-base superalloy composition may be used in single-crystal or directionally solidified superalloy articles such as high pressure turbine blades for a gas turbine engine.

Abstract: A composition comprising a glass-forming binder component and a particulate corrosion resistant component. The particulate corrosion resistant component comprises corrosion resistant particulates having: a CTEp of at least about 4 and being solid at a temperature of about 1300° F. (704° C.) or greater; and a maximum median particle size defined by one of the following formulas: (a) for a CTEp of 8 or less, an MP equal to or less than (4.375×CTEp)?10; and (b) for a CTEp of greater than 8, an Mp equal to or less than (?4.375×CTEp)+60, wherein CTEp is the average CTE of the corrosion resistant particulates and wherein Mp is the median equivalent spherical diameter (ESD), in microns, of the corrosion resistant particulates. Also disclosed is an article comprising a turbine component comprising a metal substrate and a corrosion resistant coating overlaying the metal substrate, as well as a method for forming at least one layer of the corrosion resistant coating adjacent to the metal substrate.

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 composition useful as a thermal barrier coating on a superalloy substrate intended for use in hostile thermal environments. The coating comprises zirconia stabilized in a predominately tetragonal phase. The composition includes a ceramic component consisting essentially of zirconia (ZrO2) or a combination of zirconia and hafnia (HfO2) and a stabilizer component comprising, in combination, a first co-stabilizer selected from YbO1.5, HoO1.5, ErO1.5, TmO1.5, LuO1.5, and combinations thereof, and optionally YO1.5, a second co-stabilizer selected from TiO2, PdO2, VO2, GeO2, and combinations thereof, and a third co-stabilizer comprising TaO2.5. The stabilizer component is present in an amount effective to achieve the predominantly tetragonal phase in the 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: A composition useful as a thermal barrier coating on a superalloy substrate intended for use in hostile thermal environments. The coating comprises zirconia stabilized in a predominately tetragonal phase. The composition includes a ceramic component consisting essentially of zirconia (ZrO2) or a combination of zirconia and hafnia (HfO2) and a stabilizer component comprising, in combination, a first co-stabilizer selected from YbO1.5, HoO1.5, ErO1.5, TmO1.5, LuO1.5, and combinations thereof, and a second co-stabilizer selected from TiO2, PdO2, VO2, GeO2, and combinations thereof. Optionally, the stabilizer component includes Y2O3. The stabilizer component is present in an amount effective to achieve the predominantly tetragonal phase in the coating.

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 protective coating for use on a silicon-containing substrate, and deposition methods therefor. The coating has a barium-strontium-aluminosilicate (BSAS) 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 BSAS and is substantially free of a nonstoichiometric second crystalline phase of BSAS 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: According to an embodiment of the invention, an article of manufacture for use in a gas turbine engine is disclosed. The article comprises a part having a surface covered with a ceramic thermal barrier coating. The thermal barrier coating has an outer surface covered with a sacrificial phosphate coating, wherein the sacrificial phosphate coating reacts with contaminant compositions to prevent contaminant infiltration into the thermal barrier coating.

Abstract: An article comprising a turbine component other than an airfoil having a metal substrate and a ceramic corrosion resistant coating overlaying the metal substrate. This coating has a thickness up to about one micrometer and consists of a ceramic composition that comprises a ceramic metal oxide selected from the group consisting of zirconia, hafnia and mixtures thereof. This coating can be formed by alternative methods to have different microstructures, including a dense matrix or a strain-tolerant columnar grain structure.

Abstract: A composition comprising a glass-forming binder component and a particulate corrosion resistant component. The particulate corrosion resistant component comprises corrosion resistant particulates having: a CTEp of at least about 4 and being solid at a temperature of about 1300° F. (704° C.) or greater; and a maximum median particle size defined by one of the following formulas: (a) for a CTEp of 8 or less, an MP equal to or less than (4.375×CTEp)?10; and (b) for a CTEp of greater than 8, an Mp equal to or less than (?4.375 ×CTEp)+60, wherein CTEp is the average CTE of the corrosion resistant particulates and wherein Mp is the median equivalent spherical diameter (ESD), in microns, of the corrosion resistant particulates. Also disclosed is an article comprising a turbine component comprising a metal substrate and a corrosion resistant coating overlaying the metal substrate, as well as a method for forming at least one layer of the corrosion resistant coating adjacent to the metal substrate.

Abstract: According to an embodiment of the invention, an article of manufacture for use in a gas turbine engine is disclosed. The article comprises a part having a surface covered with a ceramic thermal barrier coating. The thermal barrier coating has an outer surface covered with a sacrificial phosphate coating, wherein the sacrificial phosphate coating reacts with contaminant compositions to prevent contaminant infiltration into the thermal barrier coating.

Abstract: A composition comprising a glass-forming binder component and a particulate corrosion resistant component. The particulate corrosion resistant component comprises corrosion resistant particulates having: a CTEp of at least about 4 and being solid at a temperature of about 1300° F. (704° C.) or greater; and a maximum median particle size defined by one of the following formulas: (a) for a CTEp of 8 or less, an Mp equal to or less than (4.375×CTEp)?10; and (b) for a CTEp of greater than 8, an Mp equal to or less than (?4.375×CTEp)+60, wherein CTEp is the average CTE of the corrosion resistant particulates and wherein Mp is the median equivalent spherical diameter (ESD), in microns, of the corrosion resistant particulates. Also disclosed is an article comprising a turbine component comprising a metal substrate and a corrosion resistant coating overlaying the metal substrate, as well as a method for forming at least one layer of the corrosion resistant coating adjacent to the metal substrate.

Abstract: A composition comprising a liquid mixture having: a corrosion resistant metal particulate component comprising aluminum-containing metal particulates, wherein the aluminum-containing metal particulates have a phosphate and/or silica-containing insulating layer; a glass-forming binder component; and a liquid carrier component. Also disclosed is a method comprising the following steps: (a) providing an article comprising a metal substrate; (b) imparting to the metal substrate an electrical charge; and (c) electrostatically applying a liquid coating composition to the electrically charged metal substrate, wherein the liquid coating composition comprises a liquid mixture having: a corrosion resistant metal particulate component comprising aluminum-containing metal particulates having a phosphate and/or silica-containing insulating layer; glass-forming binder component; and a liquid carrier component.

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.

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: In accordance with an embodiment of the invention, an article is disclosed. The article comprises a gas turbine engine component substrate comprising a silicon material; and an environmental barrier coating overlying the substrate, wherein the environmental barrier coating comprises cerium oxide, and the cerium oxide reduces formation of silicate glass on the substrate upon exposure to corrodant sulfates.

Abstract: An article comprising a turbine component other than an airfoil having a metal substrate and a ceramic corrosion resistant coating overlaying the metal substrate. This coating has a thickness up to about 5 mils (127 microns) and comprises a ceramic metal oxide selected from the group consisting of zirconia, hafnia and mixtures thereof. This coating can be formed by a method comprising the following steps: (a) providing a turbine component other than an airfoil comprising the metal substrate; (b) providing a gel-forming solution comprising a ceramic metal oxide precursor; (c) heating the gel-forming solution to a first preselected temperature for a first preselected time to form a gel; (d) depositing the gel on the metal substrate; and (e) firing the gel at a second preselected temperature above the first preselected temperature to form the ceramic corrosion resistant coating comprising the ceramic metal oxide.