摘要:
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.
摘要:
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.
摘要:
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.
摘要:
Zirconia-containing ceramic compositions that are capable of providing thermal barrier coatings wherein the zirconia is stabilized in the cubic crystalline phase. These compositions comprise at least about 50 mole % zirconia and a stabilizing amount up to about 49 mole % of a stabilizer component comprising: (1) a first metal oxide selected from the group consisting of ytterbia, neodymia, mixtures of ytterbia and neodymia, mixtures of ytterbia and lanthana, mixtures of neodymia and lanthana, and mixtures of ytterbia, neodymia and lanthana in an amount of from about 5 to about 49 mole % of the composition; and (2) a second metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of about 4 mole % or less of the composition. The ceramic composition further comprises one or more of a third metal oxide selected from the group consisting of: (a) hafnia in an amount from about 0.5 to about 40 mole % of the composition; and (b) tantala in an amount of from about 0.5 to about 10 mole % of the composition. These compositions are useful in preparing thermal barrier coatings for an underlying substrate of articles that operate at, or are exposed to, high temperatures.
摘要:
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.
摘要:
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.
摘要:
A thermal barrier coating, or TBC, and method for forming the TBC. The TBC is formed of a thermal-insulating material that contains yttria-stabilized zirconia (YSZ) alloyed with at least a third oxide. The TBC is formed to also contain elemental carbon, and may potentially contain carbides and/or a carbon-containing gas that forms from the thermal decomposition of carbon. The TBC is characterized by lower density and thermal conductivity, high temperature stability and improved mechanical properties. To exhibit the desired effect, the third oxide is more particularly one that increases the lattice strain energy of the TBC microstructure as a result of having an ion size that is sufficiently different than a zirconium ion.
摘要:
A process and apparatus for depositing a ceramic coating, such as a thermal barrier coating (TBC) for a gas turbine engine component. The process deposits a coating whose composition includes multiple oxide compounds and a carbon-based constituent, e.g., elemental carbon, carbides, and carbon-based gases. The process uses at least one evaporation source to provide multiple different oxide compounds and at least one carbide compound comprising carbon and an element. The evaporation source is evaporated to produce a vapor cloud that contacts and condenses on the component surface to form the ceramic coating, and particularly so that the coating comprises the oxide compounds, an oxide of the element of the carbide compound, and the carbide compound and/or a carbon-containing gas. The process is carried out with an apparatus comprising a coating chamber in which the evaporation source is present, and a device for evaporating the evaporation source.
摘要:
A process and apparatus for depositing a ceramic coating, such as a thermal barrier coating (TBC) for a gas turbine engine component. The process deposits a coating whose composition includes multiple oxide compounds and a carbon-based constituent, e.g., elemental carbon, carbides, and carbon-based gases. The process uses at least one evaporation source to provide multiple different oxide compounds and at least one carbide compound comprising carbon and an element. The evaporation source is evaporated to produce a vapor cloud that contacts and condenses on the component surface to form the ceramic coating, and particularly so that the coating comprises the oxide compounds, an oxide of the element of the carbide compound, and the carbide compound and/or a carbon-containing gas. The process is carried out with an apparatus comprising a coating chamber in which the evaporation source is present, and a device for evaporating the evaporation source.
摘要:
An apparatus for depositing a ceramic coating on a component. The apparatus includes an evaporation source containing multiple different oxide compounds, at least one of the oxide compounds having a vapor pressure that is higher than the remaining oxide compounds, to deposit on the component a coating of the multiple oxide compounds. The apparatus further includes a device for introducing the evaporation source into a coating chamber, a device for suspending the component near the evaporation source, a device for projecting a high-energy beam on the evaporation source to melt and form a vapor cloud of the oxide compounds of the evaporation source, a device capable of preventing the vapor cloud from contacting and condensing on the component, and a device for moving the preventing device to allow the vapor cloud to contact and condense on the component.