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: 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: A gas turbine blade comprises a base metal, a platform, an airfoil extending upwardly from the platform, 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 blade has a first chromide coating contacting the base metal of at least a portion of an interior surface of the shank and interdiffused therewith, wherein the first chromide coating does not have an aluminide coating deposited over it. The blade has a second chromide coating contacting the base metal of at least a portion of an interior surface of the airfoil and interdiffused therewith. A method for preparing a gas turbine blade comprises the steps of applying chromide coatings, sealing the interior passages of the shank and airfoil and applying an aluminide or platinum aluminide coating and an optional ceramic layer on the airfoil.

Abstract: A method for applying a ceramic coating over a substantially smooth protective coating on a metal substrate is disclosed. The method includes the step of air plasma spraying (APS) particles of the ceramic coating at a pre-selected particle velocity of at least about 500 meters per second. The ceramic coating particles have an average particle size no greater than about 50 microns. An article is also described, including a metal substrate; and a substantially smooth protective coating over the substrate, having a roughness (Ra) less than about 200 micro-inches. An adherent ceramic coating is disposed on the substantially smooth protective coating.

Abstract: The present invention is a process for applying oxide paint as a touch-up paint for an oxide-based corrosion inhibiting coating with at least one imperfection region. Such oxide-based corrosion inhibiting coatings are applied on superalloy components used for moderately high temperature applications, such as the superalloy components found in the high-pressure turbine (HPT) section of a gas turbine engine, including turbine disks and seals. However, during the application of oxide-based corrosion inhibiting coatings, imperfection regions sometimes occur, exposing the superalloy substrate beneath the oxide-based corrosion inhibiting coating. Such imperfection regions can include a spalled region, a scratched region, a chipped region, an uncoated region, or combinations thereof.

Abstract: A coating process and system 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 system 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 provided. The article comprises a substrate comprised of silicon containing material, an environmental barrier coating (EBC) overlying the substrate and a thermal barrier coating (TBC) on the environmental barrier coating. The thermal barrier coating comprising a compound having a rhombohedral phase.

Abstract: A corrosion resistant tape coating for gas turbine engine includes a glassy ceramic matrix wherein the glassy matrix is silica-based, and includes corrosion resistant particles selected from refractory particles and non-refractory MCrAlX particles, and combinations thereof. The corrosion resistant particles are substantially uniformly distributed within the matrix, and provide the coating with corrosion resistance. Importantly the coating of the present invention has a coefficient of thermal expansion (CTE) greater than that of alumina at engine operating temperatures. The CTE of the coating is sufficiently close to the substrate material such that the coating does not spall after frequent engine cycling at temperatures above 1200° F.

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: 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: In accordance with an embodiment of the invention, a thermal barrier coating for inclusion in a thermal barrier coating/environmental barrier coating system (TBC/EBC system) for use on a silicon based substrate is disclosed. The thermal barrier coating comprising up to about 9 mol percent of a stabilizer and up to 91 mol percent of primary oxide selected from the group consisting of zirconia, hafnia and mixtures thereof. The stabilizer comprises: a first metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof, a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, gadolinia, neodymia, samaria, dysprosia, ytterbia, erbia, and mixtures thereof. The first metal oxide is in an amount of from about 3 to about 5 mol %, the second metal oxide is in an amount of from about 0.25 to about 6 mol %.

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: In accordance with an embodiment of the invention, a thermal barrier coating (TBC) for inclusion in a thermal barrier coating/environmental barrier coating system (TBC/EBC system) for use on a silicon containing material substrate is provided. The TBC comprises a compound having a primary constituent portion and a stabilizer portion stabilizing said primary constituent. The primary constituent portion of the TBC comprises hafnia present in an amount of at least about 5 mol % of the primary constituent. The stabilizer portion of said thermal barrier coating comprises 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: In accordance with an embodiment of the invention, a thermal barrier coating (TBC) for inclusion in a thermal barrier coating/environmental barrier coating system (TBC/EBC system) for use on a silicon containing material substrate is provided. The TBC comprises a compound having a primary constituent portion and a stabilizer portion stabilizing said primary constituent. The primary constituent portion of the TBC comprises hafnia present in an amount of at least about 5 mol % of the primary constituent. The stabilizer portion of said thermal barrier coating comprises 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 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: In accordance with an embodiment of the invention, an article is provided. The article comprises a substrate comprised of silicon containing material, an environmental barrier coating (EBC) overlying the substrate and a thermal barrier coating (TBC) on the environmental barrier coating. The thermal barrier coating comprising a compound having a rhombohedral phase.

Abstract: A coating process and system 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 system 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: Process includes providing a silicide-containing bond coat layer overlying a silicon-containing substrate, optionally forming a silica scale layer adjacent to and overlying the bond coat layer by preoxidizing the bond coat layer, and providing an environmental barrier coating overlying the bond coat layer. The environmental barrier coating includes a corrosion resistant outer layer formed by reacting a metal source with the silica scale layer, if present, or with the silicide-containing substrate in the absence of the silica scale layer. The process may include providing a thermal barrier coating overlying the corrosion resistant outer layer. The silicon-containing substrate may include at least a portion of a gas turbine engine component selected from a turbine blade, vane, and blisk.

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: An environmental coating suitable for use on turbine components, such as turbine disks and turbine seal elements, formed of alloys susceptible to oxidation and hot corrosion. The environmental coating is predominantly a solid solution phase of nickel, iron, and/or cobalt. The coating contains about 18 weight percent to about 60 weight percent chromium, which ensures the formation of a protective chromia (Cr2O3) scale while also exhibiting high ductility. The coating may further contain up to about 8 weight percent aluminum, as well as other optional additives. The environmental coating is preferably sufficiently thin and ductile to enable compressive stresses to be induced in the underlying substrate through shot peening without cracking the coating.