Abstract: An article may include a superalloy substrate and a calcia-magnesia-alumina-silicate (CMAS)-resistant thermal barrier coating (TBC) layer overlying the superalloy substrate. In some embodiments, the CMAS-resistant TBC layer includes between about 50 wt. % and about 90 wt. % of a TBC composition and between about 10 wt. % and about 50 wt. % of a CMAS-resistant composition. In some examples, the TBC composition includes at least one of yttria-stabilized zirconia, yttria-stabilized hafnia, zirconia stabilized with at least three rare earth oxides, or hafnia stabilized with at least three rare earth oxides. In some examples, the CMAS-resistant composition includes alumina, silica, and an oxide of at least one of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Yb, Dy, Ho, Er, Tm, Tb, or Lu.

Abstract: An environmental barrier coating composition for a ceramic matrix composite is provided that includes a doped rare earth disilicate layer over the ceramic matrix composite. The doped rare earth disilicate includes a disilicate having a composition of RE2Si2O7. The RE is selected from the group consisting of at least one of lutetium, ytterbium, thulium, erbium, holmium, dysprosium, terbium, gadolinium, europium, samarium, promethium, neodymium, praseodymium, cerium, lanthanum, yttrium, and scandium.

Abstract: An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

Abstract: In one example, article comprising a substrate defining an outer surface; a plurality of joint conduits formed in the outer surface of the substrate, wherein each conduit of the plurality of joint conduits exhibits an undercut configuration; and a coating formed on the outer surface of the substrate, wherein the coating substantially fills the plurality of joint conduits formed in the surface of the substrate.

Abstract: In some examples, a method includes identifying a damaged area in a ceramic matrix composite coating of an in-service component; applying a restoration slurry to the damaged area of the ceramic matrix composite coating, wherein the restoration slurry comprises a liquid carrier and a restoration coating material; drying the restoration slurry to form a dried restoration slurry; and heat treating the dried restoration slurry to form a restored portion of the ceramic matrix composite coating. In some examples, an assembly may include a component including a substrate and a coating on the substrate, where the coating defines a damaged portion; masking around the damaged portion on undamaged portions of the coating; and a restoration slurry in the damaged portion, wherein the restoration slurry comprises a liquid carrier and a restoration coating material.

Abstract: A method of making a multilayer environmental barrier coating for a ceramic matrix composite is provided, comprising the steps of: plasma spray coating an oxide-based bond coat over top of the ceramic matrix composite and depositing a columnar top coat over the oxide-based bond coat.

Abstract: A method of making a multilayer environmental barrier coating for a ceramic matrix composite is provided, comprising the steps of: plasma spray coating an oxide-based bond coat over top of the ceramic matrix composite and depositing a columnar top coat over the oxide-based bond coat.

Abstract: A vapor deposition method may include applying a first electron beam to vaporize a portion of a first target material comprising a rare earth oxide, where the first electron beam delivers a first amount of energy. The method also may include applying a second electron beam to vaporize a portion of a second target material comprising silica, where the second electron beam delivers a second amount of energy different from the first amount of energy. In some examples, the second target material is separate from the first target material. Additionally, the portion of the first target material and the portion of the second target material may be deposited substantially simultaneously over a substrate to form a layer over the substrate. A system for practicing vapor deposition methods and articles formed using vapor deposition methods are also described.

Abstract: In some examples, a method may include directing an electron beam at a coating source to create a vapor plume, wherein the coating source comprises alumina and at least one rare earth oxide. The method also may include transporting the vapor plume using a gas stream provided adjacent to the coating source to within an internal cavity defined by a surface of a substrate of a gas turbine engine blade, vane, blade track, or combustor liner, and wherein the substrate comprises at least one of a silicon-containing ceramic or a ceramic matrix composite. Additionally, the method may include depositing the alumina and the at least one rare earth oxide from the vapor plume over the surface of the internal cavity to form a calcia-magnesia-alumina-silicate (CMAS)-resistant environmental barrier coating (EBC) comprising the alumina and the at least one rare earth oxide.

Abstract: A thermal barrier coating composition for a ceramic matrix composite is provided. The thermal barrier coating comprises a porous layer and a doped rare earth disilicate layer. The porous layer is located over the doped rare earth disilicate layer. The porous layer includes a fugitive material.

Abstract: A system may include a blade track or blade shroud and a gas turbine blade that includes a blade tip. The blade track or blade shroud may include a substrate and an abradable layer formed over the substrate. The abradable layer may include at least one of zirconia or hafnia; ytterbia; samaria; and at least one of lutetia, scandia, ceria, gadolinia, neodymia, or europia. The abradable layer may include a porosity between about 25 vol. % and about 50 vol. %. The blade track or blade shroud and the gas turbine blade may be configured so the blade tip contacts a portion of the abradable layer during rotation of the gas turbine blade, and the abradable layer may be configured to be abraded by the contact by the blade tip.

Abstract: A bond layer may include a composition that may be stable at temperatures above about 1410° C. An article may include a substrate, a bond layer formed on the substrate, and an overlayer formed over the bond layer. In some examples, the bond layer may include a substantially homogeneous mixture of Si and at least one of SiO2, Al2O3, ZrO2, a rare earth oxide, ZrSiO4, TiO2, Ta2O5, B2O3, an alkali metal oxide, or an alkali earth metal oxide. In other examples, the bond layer may include Si, an alkali metal oxide, and at least one of SiO2, Al2O3, ZrO2, HfO2, a rare earth oxide, ZrSiO4, HfSiO4, TiO2, Ta2O5, B2O3, or an alkali earth metal oxide. In other examples, the bond layer may include B2O3.

Abstract: A coating including a CMAS-resistant layer with a rare earth oxide. The CMAS-resistant layer is essentially free of zirconia and hafnia, and may further include at least one of alumina, silica, and combinations thereof.

Abstract: An article may include a superalloy substrate and a calcia-magnesia-alumina-silicate (CMAS)-resistant thermal barrier coating (TBC) layer overlying the superalloy substrate. In some embodiments, the CMAS-resistant TBC layer includes between about 50 wt. % and about 90 wt. % of a TBC composition and between about 10 wt. % and about 50 wt. % of a CMAS-resistant composition. In some examples, the TBC composition includes at least one of yttria-stabilized zirconia, yttria-stabilized hafnia, zirconia stabilized with at least three rare earth oxides, or hafnia stabilized with at least three rare earth oxides. In some examples, the CMAS-resistant composition includes alumina, silica, and an oxide of at least one of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Yb, Dy, Ho, Er, Tm, Tb, or Lu.

Abstract: An article comprising a substrate, a calcia-magnesia-alumina-silicate-resistant (CMAS-resistant) layer or a plurality thereof, including a rare earth oxide and alumina formed over the substrate, and a barrier coating layer formed on the CMAS-resistant layer. The barrier coating layer or a plurality thereof, comprising a thermal barrier coating composition or an environmental barrier coating composition.

Abstract: A multilayer thermal barrier coating (TBC) may include a plurality of layers selected to provide properties to the multilayer TBC. For example, a multilayer TBC may include a first layer deposited over a substrate, a second layer deposited over the first layer and a third layer deposited over the second layer. The first layer may be selected to provide thermal cycling resistance, the second layer may be selected to provide low thermal conductivity and the third layer may be selected to provide at least one of erosion resistance and CMAS degradation resistance. The multilayer TBC may also include two layers, or more than three layers.

Abstract: An article may include a substrate comprising a matrix material and a reinforcement material, a layer formed on the substrate, an array of features formed on the layer, and a coating formed on the layer and the array of features. The article may have improved thermal and/or mechanical stress tolerance compared to an article not including the array of features formed on the layer.

Abstract: An abradable coating may include a rare earth silicate. The abradable coating may be deposited over a substrate, an environmental barrier coating, or a thermal barrier coating. The abradable coating may be deposited on a gas turbine blade track or a gas turbine blade shroud to form a seal between the gas turbine blade track or gas turbine blade shroud and a gas turbine blade. The abradable coating may also include a plurality of layers, such as alternating first and second layers including, respectively, a rare earth silicate and stabilized zirconia or stabilized hafnia.

Abstract: An abradable coating may include a rare earth silicate. The abradable coating may be deposited over a substrate, an environmental barrier coating, or a thermal barrier coating. The abradable coating may be deposited on a gas turbine blade track or a gas turbine blade shroud to form a seal between the gas turbine blade track or gas turbine blade shroud and a gas turbine blade. The abradable coating may also include a plurality of layers, such as alternating first and second layers including, respectively, a rare earth silicate and stabilized zirconia or stabilized hafnia.

Abstract: An article may include a substrate defining a surface imperfection and a coating deposited over the substrate. The coating does not substantially reproduce the surface imperfection, and the coating comprises mullite and at least one rare earth silicate, rare earth oxide, alumina, boron oxide, alkali metal oxide, alkali earth metal oxide, silicon, barium strontium aluminosilicate, barium aluminosilicate, strontium aluminosilicate, calcium aluminosilicate, magnesium aluminosilicate, or lithium aluminosilicate. In some examples, the coating may be a first coating deposited from a slurry over the substrate, and a second coating may be deposited over the first coating. In other examples, a first coating that substantially reproduces the surface imperfection may be deposited over the substrate, and the coating that does not substantially reproduce the surface imperfection may be deposited over the first coating.