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 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 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 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: An article comprising a substrate formed of a silicon-comprising material, such as an article exposed to the hostile thermal environment of a gas turbine engine. The article further comprises an environmental barrier layer, e.g., an alkaline earth metal aluminosilicate, and a top coat comprising hafnia stabilized with from about 0.5 mole % to about 10 mole % of an oxide of a metal selected from the group consisting of magnesium, calcium, scandium, yttrium, and lanthanide metals, and mixtures thereof. The article optionally comprises a transition layer between the environmental barrier layer and the top coat. A method for preparing a thermal/environmental barrier coating on a substrate formed of a silicon-comprising material is also disclosed.

Abstract: Thermal barrier coating (TBC) and a method of depositing a TBC having a modulated columnar microstructure that exhibits increased impact resistance. The TBC is deposited to have a columnar microstructure in which columns extend from a substrate surface. The columns having inner regions contacting the surface, outer regions near an outermost surface of the TBC, and interior regions therebetween. The inner regions of the columns are substantially normal to the substrate surface and at least one of the interior and outer regions of the columns are nonaligned with its respective inner regions, so that the columns of the columnar microstructure are continuous but modulated between the inner and outer regions to reduce tensile stresses within the columns resulting from particle impact.

Abstract: A composition comprising a particulate corrosion resistant component, and a glass-forming binder component. The particulate corrosion resistant component comprises from 0 to about 95% alumina particulates, and from about 5 to 100% corrosion resistant non-alumina particulates having a CTE greater than that of the alumina particulates. Also disclosed is an article comprising a turbine component comprising a metal substrate and a corrosion resistant coating having thickness up to about 10 mils (254 microns) overlaying the metal substrate. At least the layer of this coating adjacent to the metal substrate comprises a glass-forming binder component and the particulate corrosion resistant component adhered to the glass-forming binder component.

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 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: 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: An article comprising a substrate formed of a silicon-comprising material, such as an article exposed to the hostile thermal environment of a gas turbine engine. The article further comprises an environmental barrier layer, e.g., an alkaline earth metal aluminosilicate, and a top coat comprising zirconia or hafnia stabilized with up to about 10 mole % of an oxide of a metal selected from the group consisting of magnesium, calcium, scandium, yttrium, and lanthanide metals, and mixtures thereof. The article further comprises a transition layer between the environmental barrier layer and the top coat, the transition layer comprising zirconia or hafnia stabilized with up to about 10 mole % of an oxide of a metal selected from the group consisting of magnesium, calcium, scandium, yttrium, and lanthanide metals; and a low CTE oxide selected from the group consisting of niobia and tantala; and mixtures thereof.

Abstract: An article comprising a substrate formed of a silicon-comprising material, such as an article exposed to the hostile thermal environment of a gas turbine engine. The article further comprises an environmental barrier layer, e.g., an alkaline earth metal aluminosilicate, and a top coat comprising zirconia or hafnia stabilized with an oxide of a metal selected from the group consisting of magnesium, calcium, scandium, yttrium, and lanthanide metals, and mixtures thereof. The article further comprises a transition layer between the environmental barrier layer and the top coat, the transition layer comprising zirconia or hafnia stabilized with an oxide of a metal selected from the group consisting of magnesium, calcium, scandium, yttrium, and lanthanide metals; and a low CTE oxide selected from the group consisting of niobia and tantala; and mixtures thereof. A method for preparing a thermal/environmental barrier coating system on a substrate formed of a silicon-comprising material is also disclosed.

Abstract: A non-destructive method of detecting and measuring machining induced surface defects on gas turbine engine components is provided. In an exemplary embodiment, the method includes positioning an evanescent microwave microscope probe adjacent a turbine component surface, and scanning the turbine component surface by moving at least one of the evanescent microwave microscope probe and the component surface in an x-y plane while maintaining a predetermined distance between the probe and the component surface constant.

Abstract: A turbine engine rotor component, such as a compressor or turbine disk or seal element, is protected from corrosion by depositing an aluminum or chromium coating on the component. The deposition can be performed by a vapor deposition process, such as metal organic chemical vapor deposition (MOCVD), to a coating thickness of from about 0.2 to about 50 microns, typically from about 0.5 to about 3 microns. In one embodiment, the method is conducted in a vapor coating container having a hollow interior coating chamber, and includes the steps of loading the coating chamber with the component to be coated; and flowing a tri-alkyl aluminum or chromium carbonyl coating gas into the loaded coating chamber at a specified temperature, pressure, and time to deposit an aluminum or chromium coating on the surface of the component. The coated component is then heated in a nonoxidizing atmosphere to a specified temperature to form an aluminide or chromide coating on the surface.

Abstract: A non-destructive method of detecting and measuring machining induced surface defects on gas turbine engine components is provided. In an exemplary embodiment, the method includes positioning an evanescent microwave microscope probe adjacent a turbine component surface, and scanning the turbine component surface by moving at least one of the evanescent microwave microscope probe and the component surface in an x-y plane while maintaining a predetermined distance between the probe and the component surface constant.