摘要:
A method of repairing a thermal barrier coating on an article designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method is particularly suited for the repair of thermal barrier coatings composed of a metallic bond layer formed on the surface of the article, and a columnar ceramic layer overlaying the bond layer. The method entails the steps of cleaning the bond layer exposed by localized spallation, treating the bond layer so as to texture its exposed surface, and then depositing a ceramic material on the surface of the bond layer so as to form a ceramic repair layer that completely covers the bond layer. Deposition of the repair layer can be carried out such that its upper surface projects above the adjacent ceramic layer, followed by abrading the repair layer to a height substantially level with the ceramic layer.
摘要:
An article coated with a thermal barrier coating system for high temperature use, has its thermal cyclic spallation life improved by the application of an aluminide to the outer portion of a bonding coating disposed on a substrate. The bond coating has a surface roughness in the range of about 200-600 microinches Ra prior to application of covering thermal barrier coating.
摘要:
A thermal barrier coating system for high temperature superalloys includes an intermetallic bond coating on the substrate and a ceramic topcoat having a columnar grain structure with the columnar axis perpendicular to the surface of the coating. The intermetallic coating is preferably a nickel aluminide or a platinum aluminide, whose upper surface is oxidized during processing to form a thin layer of predominantly aluminum oxide. The ceramic topcoat is preferably zirconium oxide having from about 6 to 20 percent yttrium oxide.
摘要:
A method for producing a thermal barrier coating/environmental barrier coating system on a silicon containing material substrate includes applying an environmental barrier coating (EBC) over the silicon containing material substrate; and applying a thermal barrier coating (TBC) over the EBC. The thermal barrier coating includes a compound having a primary constituent portion and a stabilizer portion stabilizing said primary constituent. The primary constituent portion of the thermal barrier coating includes hafnia present in an amount of at least about 5 mol % of the primary constituent and the stabilizer portion of said thermal barrier coating includes 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.
摘要:
A gas turbine engine turbine blade comprising an airfoil section, a platform section, an under platform section, and a dovetail section, an exterior surface of the dovetail section comprising a shank exterior surface and a serrated exterior surface. The blade further comprises a silicon-modified diffusion aluminide layer a surface of a turbine blade section selected from the group consisting of an exterior surface of the under platform section, the exterior surface of the dovetail section, and combinations thereof, the silicon modified diffusion aluminide layer having a concentration of silicon at a surface of the silicon-modified diffusion aluminide layer in the range of about 1 weight percent to about 10 weight percent and a concentration of aluminum at the surface of the silicon modified diffusion aluminide layer in the range of about 5 weight percent to about 25 weight percent.
摘要:
According to an embodiment of the invention, an article of manufacture for use in a gas turbine engine is disclosed. The article comprises a part having a surface covered with a ceramic thermal barrier coating. The thermal barrier coating has an outer surface covered with a sacrificial phosphate coating, wherein the sacrificial phosphate coating reacts with contaminant compositions to prevent contaminant infiltration into the thermal barrier coating.
摘要:
A method for making a gas turbine engine turbine blade comprising an airfoil section a platform section, an under platform section, and a dovetail section, the exterior surface of the dovetail section comprising a shank exterior surface and a serrated exterior surface. The blade further includes a silicon-modified diffusion aluminide layer 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 aluminide layer having a concentration of silicon at a surface of the aluminide layer in the range of about 1 weight percent to about 10 weight percent and a concentration of aluminum at the surface of the aluminide layer in the range of about 5 weight percent to about 25 weight percent.
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:
A coating applied as a two layer system. The outer layer is an oxide of a group IV metal selected from the group consisting of zirconium oxide, hafnium oxide and combinations thereof, which are doped with an effective amount of a lanthanum series oxide. These metal oxides doped with a lanthanum series addition comprises a high weight percentage of the outer coating. As used herein, lanthanum series means an element selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu) and combinations thereof, and lanthanum series oxides are oxides of these elements. When the zirconium oxide is doped with an effective amount of a lanthanum series oxide, a dense reaction layer is formed at the interface of the outer layer of TBC and the CMAS. This dense reaction layer prevents CMAS infiltration below it. The second layer, or inner layer underlying the outer layer, comprises a layer of partially stabilized zirconium oxide.
摘要:
A heat shield which is adapted to be formed on an article which must operate in an environment in which the article is subject to thermal radiation while at an elevated service temperature. The heat shield is composed of a barrier layer formed or deposited on the surface of the article, and a reflective layer on the barrier layer. The reflective layer serves to reflect a majority of the thermal radiation which is incident on the article. The barrier layer serves to substantially prevent degradation of the reflective layer at the elevated service temperature, so as to prevent the reflectivity of the reflective layer from being degraded while the article is in service. The reflective layer is preferably a noble metal, a noble metal alloy or aluminum, while the barrier layer is preferably a nitride, aluminum oxide, yttria-stabilized zirconia, or an oxide which can be grown by oxidation of the article's surface.