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: 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: According to an embodiment of the invention, disclosed is a composite comprising a porous thermal barrier coating on a metallic part and an impermeable barrier coating adjacent to the outer surface of the thermal barrier coating. The impermeable barrier coating is dense and non-porous and comprises a rare earth silicate, the impermeable barrier coating thereby preventing infiltration of the contaminant composition into the thermal barrier coating.

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: A thermal barrier coating (TBC) for a component intended for use in a hostile environment, such as a component of a gas turbine engine. The TBC exhibits improved impact and erosion resistance as a result of being a composite material consisting essentially of particles of a ceramic reinforcement material dispersed in a ceramic matrix material. The ceramic reinforcement material has a yield strength greater than the ceramic matrix material at about 1100° C., and the particles of the ceramic reinforcement material have an average maximum dimension of greater than five micrometers.

Abstract: A corrosion resistant coating for engine components such as turbine disks, turbine seal elements and turbine shafts. This coating may also find application to other turbine components that are subjected to high temperatures and corrosive environments, such as turbine components located within or on the boundary of the gas fluid flow path, including for example turbine blades, turbine vanes, liners and exhaust flaps. The corrosion resistant coating of the present invention in service on a gas turbine component includes a glassy ceramic matrix wherein the glassy matrix is silica-based and particles selected from the group consisting of refractory oxide particles, MCrAlX particles and combinations of these particles, substantially uniformly distributed within the matrix. The refractory oxide and/or the MCrAlX provides the coating with corrosion resistance. Importantly the coating of the present invention has a coefficient of thermal expansion (CTE) greater than alumina.

Abstract: A process for protecting a thermal barrier coating. The process entails applying to a surface of the coating a liquid containing one or more of aluminum alkoxides, aluminum beta-diketonates, aluminum carboxylates, and aluminum alkyls. The liquid is applied so as to form a liquid film on the surface, and has viscosity and wetting properties that cause the liquid to infiltrate porosity within the coating beneath its surface. The coating is then heated to convert the alumina precursor to alumina. A first portion of the alumina forms a surface deposit on the coating surface, while a second portion of the alumina forms an internal deposit within the porosity of the coating. The surface deposit overlying the coating is available for sacrificial reaction with CMAS, and the internal deposit maintains a level of CMAS protection in the event the surface deposit is breached or lost through spallation, erosion, and/or consumption.

Abstract: The present invention is a gas turbine engine turbine blade comprising an airfoil section having at least an exterior surface, a platform section having an exterior surface, an under platform section having an exterior surface, and a dovetail section having an exterior surface. The blade further comprises a corrosion resistant coating on a surface of a turbine blade section selected from the group consisting of the exterior surface of the under platform section, the exterior surface of the dovetail section, and combinations thereof, the corrosion resistant coating comprising a particulate corrosion resistant component comprising from about 5 weight percent to about 100 weight percent corrosion resistant non-alumina particulates having a CTE greater than that of alumina particulates and balance alumina particulates, and a binder component. The present invention also includes methods for making such a gas turbine engine blade.

Abstract: An intermetallic composition suitable for use as an environmentally-protective coating on surfaces of components used in hostile thermal environments, including the turbine, combustor and augmentor sections of a gas turbine engine. The coating contains the gamma-prime (Ni3Al) nickel aluminide intermetallic phase and either the beta (NiAl) nickel aluminide intermetallic phase or the gamma solid solution phase. The coating has an average aluminum content of 14 to 30 atomic percent and an average platinum-group metal content of at least 1 to less than 10 atomic percent, the balance of the coating being nickel, incidental impurities, and optionally hafnium.

Abstract: An intermetallic composition suitable for use as an environmentally-protective coating on surfaces of components used in hostile thermal environments, including the turbine, combustor and augmentor sections of a gas turbine engine. The coating contains the gamma-prime (Ni3Al) nickel aluminide intermetallic phase and either the beta (NiAl) nickel aluminide intermetallic phase or the gamma solid solution phase. The coating has an average aluminum content of 14 to 30 atomic percent and an average platinum-group metal content of at least 1 to less than 10 atomic percent, the balance of the coating being nickel, one or more of chromium, silicon, tantalum, and cobalt, optionally one or more of hafnium, yttrium, zirconium, lanthanum, and cerium, and incidental impurities.

Abstract: An article comprising a silicon-containing substrate, an environmental barrier coating (EBC) overlying the substrate, wherein the EBC comprises a higher metal silicate-containing outer barrier layer; and a corrosion resistant alumina/aluminate sealant for the higher metal silicate-containing outer barrier layer. A process is also provided for forming a corrosion resistant alumina/aluminate sealant layer over the higher metal silicate-containing outer barrier layer.

Abstract: An article comprising a silicon-containing substrate, an environmental barrier coating (EBC) overlying the substrate, wherein the EBC comprises an outer alkaline earth aluminosilicate barrier layer; and a corrosion resistant alumina/aluminate sealant for the outer barrier layer. A process is also provided for forming a corrosion resistant alumina/aluminate sealant layer over the outer barrier layer of the EBC. Also provided is an alternative process for treating a porous outer barrier layer with a liquid composition comprising an corrosion resistant alumina/aluminate sealant precursor to infiltrate the porous outer barrier layer with the alumina/aluminate sealant precursor in an amount sufficient to provide, when converted to the corrosion resistant alumina/aluminate sealant, protection of the environmental barrier coating against environmental attack; and converting the infiltrated alumina/aluminate sealant precursor within the porous outer barrier layer to the corrosion resistant alumina/aluminate sealant.

Abstract: An article comprising a silicon-containing substrate, a silicide-containing bond coat layer overlying the substrate, and an environmental barrier coating (EBC) overlying the bond coat layer, wherein the EBC comprises a corrosion resistant outer layer comprising a corrosion resistant metal silicate. A process is also provided for forming the corrosion resistant outer layer over the silicide-containing bond coat layer.

Abstract: A coating system for Si-containing materials, particularly Si-based composites used to produce articles exposed to high temperatures. The coating system is a compositionally-graded thermal/environmental barrier coating (T/EBC) system that includes an intermediate layer containing yttria-stabilized hafnia (YSHf) and mullite, alumina and/or an aluminosilicate, which is used in combination with an inner layer between a Si-containing substrate and the intermediate layer and a thermal-insulating top coat overlying the intermediate layer. The intermediate layer provides environmental protection to the silicon-containing substrate, and has a coefficient of thermal expansion between that of the top coat and that of the inner layer so as to serve as a transition layer therebetween. The intermediate layer is particular well suited for use in combination with an inner layer of an alkaline earth metal aluminosilicate (such as BSAS) and a top coat formed of YSZ or YSHf.

Abstract: An article comprising a silicon-containing substrate, a silicide-containing bond coat layer overlying the substrate, and typically an environmental barrier coating overlaying the bond coat layer. An article is also provided wherein the environmental barrier coating comprises: (1) an optional inner silica scale layer overlaying the bond coat layer; (2) intermediate layer overlaying the inner silica scale layer, or the bond coat layer in the absence of the inner silica scale layer, and comprising mullite, or a combination of mullite with a barium strontium aluminosilicate, a yttrium silicate, or a calcium aluminosilicate; and (3) an outer steam-resistant barrier layer overlaying the intermediate layer and consisting essentially of an alkaline earth silicate/aluminosilicate. Processes are also provided for forming the silicide-containing bond coat layer over the substrate, followed by forming the environmental barrier coating over the bond coat layer.

Abstract: A coating system for Si-containing materials, particularly those for articles exposed to high temperatures. The coating system exhibits improved resistance to corrosion from sea salt and CMAS as a result of using aluminate compounds to protect silicate-containing layers of the coating system. The coating system includes an environmental barrier coating, a thermal barrier coating overlying the environmental barrier coating and formed of a thermal-insulating material, and a transition layer between the environmental barrier coating and thermal barrier coating, wherein the transition layer contains at least one aluminate compound and/or alumina.

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.

Abstract: An article comprising a silicon-containing substrate, a steam-resistant barrier coating overlaying the substrate, wherein the steam-resistant barrier coating comprises an outer barrier layer consisting essentially of an alkaline earth aluminate/aluminosilicate, and a corrosion resistant metal silicate protective layer overlaying and adjacent to the outer barrier layer. A process is also provided for forming on the outer barrier layer the corrosion resistant metal silicate protective layer.

Abstract: An article comprising a silicon carbide and/or silicon metal-containing substrate and an environmental barrier layer overlaying the substrate, wherein the environmental barrier layer has a thickness up to about 5 mils (127 microns) and comprises a reaction-generated corrosion resistant metal silicate. A process is also provided for reacting a metal source and a silica source over the silicon carbide and/or silicon metal-containing substrate to form the environmental barrier layer comprising the reaction-generated corrosion resistant metal silicate.

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.