Abstract: According to an embodiment of the invention, a repaired component is disclosed. The repaired component comprises an engine run component having a base metal substrate, a portion of the base metal substrate between about 1-3 mils in thickness and an overlying bond coat having been removed to create a remaining base metal substrate of reduced thickness. The repaired component further comprises a lower growth environmental bond coating comprising an alloy having an aluminum content of about 10-60 atomic percent applied to the remaining base metal substrate so that upon subsequent repair of the component, less than about 1-3 mils in thickness of the remaining base metal substrate is removed because of less environmental coating growth into the substrate than the prior bond coat. Advantageously, the repaired component has extended component life and increased repairability.

Abstract: A PVD process and apparatus for depositing a coating from multiple sources of materials with different vapor pressures. The process entails forming molten pools of different first and second materials in a coating chamber of the apparatus, supporting an article within the chamber, and evaporating the molten pools with an energy beam to deposit a coating on the article with a controlled composition that contains at least a first metal and a relatively lesser amount of at least one reactive metal having a lower vapor pressure than the first metal. The first material contains at least the first metal, and the second material contains the reactive metal and at least a second metal. The second and reactive metals are combined to cause the second material to have a lower melting temperature and wider melting range than the reactive metal.

Abstract: A beta-phase nickel aluminide (NiAl) overlay coating (24) and method for modifying the grain structure of the coating (24) to improve its oxidation resistance. The coating (24) is deposited by a method that produces a grain structure characterized by grain boundaries (44) exposed at the outer coating surface (36). The grain boundaries (44) may also contain precipitates (40) as a result of the alloyed chemistry of the coating (24). During or after deposition, the overlay coating (24) is caused to form new grain boundaries (34) that, though open to the outer surface (36) of the coating (24), are free of precipitates or contain fewer precipitates (40) than the as-deposited grain boundaries (44). New grain boundaries (34) are preferably produced by causing the overlay coating (24) to recrystallize during coating deposition or after deposition as a result of a surface treatment followed by heat treatment.

Abstract: A coating and process for depositing the coating on a substrate. The coating is a nickel aluminide overlay coating of predominantly the beta (NiAl) and gamma-prime (Ni3Al) intermetallic phases, and is suitable for use as an environmental coating and as a bond coat for a thermal barrier coating (TBC). The coating can be formed by depositing nickel and aluminum in appropriate amounts to yield the desired beta+gamma prime phase content. Alternatively, nickel and aluminum can be deposited so that the aluminum content of the coating exceeds the appropriate amount to yield the desired beta+gamma prime phase content, after which the coating is heat treated to diffuse the excess aluminum from the coating into the substrate to yield the desired beta+gamma prime phase content.

Abstract: An overlay coating for articles used in hostile thermal environments. The coating has a predominantly gamma prime-phase nickel aluminide (Ni3Al) composition suitable for use as an environmental coating and as a bond coat for a thermal barrier coating. The coating has a composition of, by weight, at least 6% to about 15% aluminum, about 2% to about 5% chromium, optionally one or more reactive elements in individual or combined amounts of up to 4%, optionally up to 2% silicon, optionally up to 60% of at least one platinum group metal, and the balance essentially nickel. A thermal-insulating ceramic layer may be deposited on the coating.

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 protected article includes a substrate having a surface and a substrate aluminum content. A first protective layer overlies a first region of the surface of the substrate, wherein the first protective layer has a composition having a first-protective-layer aluminum content at least 3 atomic percent greater than the substrate aluminum content. A second protective layer overlies a second region of the surface of the substrate different from the first region, wherein the second protective layer has a composition with at least about 60 percent by weight of platinum, rhodium, or palladium, and combinations thereof.

Abstract: A strengthened bond coat for improving the adherence of a thermal barrier coating to an underlying metal substrate to resist spallation without degrading oxidation resistance of the bond coat. The bond coat comprises a bond coating material selected from the group consisting of overlay alloy coating materials, aluminide diffusion coating materials and combinations thereof. Particles comprising a substantially insoluble bond coat strengthening compound and having a relatively fine particle size of about 2 microns or less are dispersed within at least the upper portion of the bond coat in an amount sufficient to impart strengthening to the bond coat, and thus limit ratcheting or rumpling thereof.

Abstract: According to an embodiment of the invention, a method for repairing a coated high pressure turbine blade, which has been exposed to engine operation, to restore coated airfoil contour dimensions of the blade, and improve upon the prior bond coat is disclosed. The method comprises providing an engine run high pressure turbine blade including a base metal substrate made of a nickel-based alloy and having thereon a thermal barrier coating system. The thermal barrier coating system comprises a diffusion bond coat on the base metal substrate and a top ceramic thermal barrier coating comprising a yttria stabilized zirconia material. The top ceramic thermal barrier coating has a nominal thickness t. The method further comprises removing the thermal barrier coating system, wherein a portion of the base metal substrate also is removed, and determining the thickness of the base metal substrate removed. The portion of the base metal substrate removed has a thickness, ?t.

Abstract: A coating and coating process for incorporating surface features on an air-cooled substrate surface of a component for the purpose of promoting heat transfer from the component. The coating process generally comprises depositing a first metallic coating material on the surface of the component using a first set of coating conditions to form a first environmental coating layer, and then depositing a second metallic coating material using a second set of coating conditions that differ from the first set, such that an outer environmental coating layer is formed having raised surface features that cause the surface of the outer environmental coating layer to be rougher than the surface of the first environmental coating layer.

Abstract: In one embodiment of the invention, a NiAl overlay bond coating composition comprises a NiAl alloy. The alloy comprises Zr and at least one modifying element in an amount effective to form a stabilized oxide structure comprising stabilized zirconia including a substantially tetragonal structure upon oxidation of the alloy. The tetragonal structure is stabilized such that it does not change phases and revert to a monoclinic or monoclinic and tetragonal structure, which is not substantially tetragonal, upon thermal cycling.

Abstract: An article and TBC coating system thereon that in combination exhibit significantly improved spallation resistance. The article comprises a substrate formed of a metal alloy containing ruthenium and one or more refractory elements (e.g., tantalum, tungsten, molybdenum, rhenium, hafnium, etc.). The substrate is protected by a coating system comprising an aluminum-containing bond coat on the surface of the substrate and a ceramic coating bonded to the substrate by the bond coat. The bond coat, preferably an aluminide, is deposited so as to be substantially free of ruthenium, though ruthenium is present in the bond coat as a result of diffusion from the substrate into the bond coat.

Abstract: A strengthened bond coat for improving the adherence of a thermal barrier coating to an underlying metal substrate to resist spallation without degrading oxidation resistance of the bond coat. The bond coat comprises a bond coating material selected from the group consisting of overlay alloy coating materials, aluminide diffusion coating materials and combinations thereof. Particles comprising a substantially insoluble bond coat strengthening compound and having a relatively fine particle size of about 2 microns or less are dispersed within at least the upper portion of the bond coat in an amount sufficient to impart strengthening to the bond coat, and thus limit ratcheting or rumpling thereof.

Abstract: According to an embodiment of the invention, a repaired component is disclosed. The repaired component comprises an engine run component having a base metal substrate, a portion of the base metal substrate between about 1-3 mils in thickness and an overlying bond coat having been removed to create a remaining base metal substrate of reduced thickness. The repaired component further comprises a lower growth environmental bond coating comprising an alloy having an aluminum content of about 10-60 atomic percent applied to the remaining base metal substrate so that upon subsequent repair of the component, less than about 1-3 mils in thickness of the remaining base metal substrate is removed because of less environmental coating growth into the substrate than the prior bond coat. Advantageously, the repaired component has extended component life and increased repairability.

Abstract: According to an embodiment of the invention, a method for repairing a coated high pressure turbine blade, which has been exposed to engine operation, to restore coated airfoil contour dimensions of the blade, is disclosed. The method comprises providing an engine run high pressure turbine blade including a base metal substrate made of a nickel-based alloy and having thereon a thermal barrier coating system. The thermal barrier coating system comprises a diffusion bond coat on the base metal substrate and a top ceramic thermal barrier coating comprising a yttria stabilized zirconia material. The top ceramic thermal barrier coating has a nominal thickness t. The method further comprises removing the thermal barrier coating system, wherein a portion of the base metal substrate also is removed, and determining the thickness of the base metal substrate removed. The portion of the base metal substrate removed has a thickness, ?t.

Abstract: A masking material and a method for applying the masking material to preselected surfaces of a component to protect the surfaces to which the masking material is applied from exposure to a vapor phase of aluminum gas while a protective environmental coating is applied to other surfaces of the component. The component, such as found in the hot section of a gas turbine engine, typically has intricate internal passageways. A ceramic material is applied as a mask over preselected surfaces while leaving remaining surfaces of a component exposed. The component typically is a superalloy component, and the exposed surfaces are to be coated with an environmental protective coating. The surfaces are preselected on the basis of whether coating is desired on the surface. The ceramic material forms a continuous, crack-free mask on these preselected surfaces without obstructing the internal passageways. The ceramic material which forms a mask is stable at the elevated temperatures of environmental coating application.

Abstract: The present invention is process for forming diffusion aluminide coatings on an uncoated surface of a substrate, without interdiffusing a sufficient amount of aluminum into a coating layer to adversely affect the coating growth potential and mechanical properties of said coating layer. A metal substrate is provided comprising an external surface and an internal passage therein defined by an internal surface, at least a portion of the external surface of the substrate being coated with a coating layer selected from the group consisting of ?-NiAl-base, MCrAlX, a line-of-sight diffusion aluminide, a non-line-of-sight diffusion aluminide, a pack diffusion aluminide, and a slurry diffusion aluminide on said substrate. The external surface of the substrate is cleaned. The metal substrate is subjected to a aluminum vapor phase deposition process performed using a fluorine-containing activator selected from the group consisting of AlF3, CrF3, NH4F, and combinations thereof, at a rate in the range of about 0.

Abstract: A beta-phase NiAl overlay coating containing a dispersion of ceramic particles and a process for depositing the overlay coating. If the coating is used to adhere a thermal barrier coating (TBC), the TBC exhibits improved spallation resistance as a result of the dispersion of ceramic particles having a dispersion-strengthening effect on the overlay coating. The overlay coating contains at least one reactive element and is deposited so that the some of the reactive element deposits as the ceramic particles dispersed in the overlay coating.

Abstract: A method for producing an article such as a turbine component that is coated with a ?-phase, high aluminum content coating, such as substantially stoichiometric NiAl, and which has a surface finish suitable for application of a ceramic topcoat. The method involves heating the coated article to near the brittle-ductile transition temperature of the coating and impacting the coating with particles of a preselected size so that the brittle coating is not adversely affected by chipping or breakage. The impacting produces a surface finish of 120 micro-inches or finer so that a ceramic thermal barrier layer can be applied over the coating. The preferred method of improving the surface finish utilizes heated peening media to impact the heated coated article, thus allowing use of a broader selection of peening media.

Abstract: A beta-phase nickel aluminide (NiAl) overlay coating (24) and method for modifying the grain structure of the coating (24) to improve its oxidation resistance. The coating (24) is deposited by a method that produces a grain structure characterized by grain boundaries (44) exposed at the outer coating surface (36). The grain boundaries (44) may also contain precipitates (40) as a result of the alloyed chemistry of the coating (24). During or after deposition, the overlay coating (24) is caused to form new grain boundaries (34) that, though open to the outer surface (36) of the coating (24), are free of precipitates or contain fewer precipitates (40) than the as-deposited grain boundaries (44). New grain boundaries (34) are preferably produced by causing the overlay coating (24) to recrystallize during coating deposition or after deposition as a result of a surface treatment followed by heat treatment.