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: In some examples, a method may include depositing, from a slurry comprising particles including silicon metal, a bond coat precursor layer including the particles comprising silicon metal directly on a ceramic matrix composite substrate. The method also may include locally heating the bond coat precursor layer to form a bond coat comprising silicon metal. Additionally, the method may include forming a protective coating on the bond coat. In some examples, an article may include a ceramic matrix composite substrate, a bond coat directly on the substrate, and a protective coating on the bond coat. The bond coat may include silicon metal and a metal comprising at least one of Zr, Y, Yb, Hf, Ti, Al, Cr, Mo, Nb, Ta, or a rare earth metal.

Abstract: An apparatus includes a ceramic matrix composite (CMC) component and an interface coating on the CMC component, wherein the interface coating includes a layer of at least one of the following compositions: 40-50 wt % Nb, 28-42 wt % Al, 4-15 wt % Cr, 1-2 wt % Si; 90-92 wt % Mo, 4-5 wt % Si, 4-5 wt % B; or 60-80 wt % V, 20-30 wt % Cr, 2-15 wt % Ti.

Abstract: In some examples, a coating may include at least one feature that facilitates visual determination of a thickness of the coating. For example, the coating may include a plurality of microspheres disposed at a predetermined depth of the coating. The plurality of microspheres may define a distinct visual characteristic. By inspecting the coating and viewing at least one of the microspheres, the thickness of the coating may be estimated. In some examples, the plurality of microspheres may be embedded in a matrix material, and the distinct visual characteristic of the microspheres may be different than the visual characteristic of the matrix material. In other examples, the at least one feature may include at least one distinct layer in the coating system that includes a distinct visual characteristic, such as a color of the distinct layer.

Abstract: An apparatus includes a ceramic matrix composite (CMC) component and an interface coating on the CMC component, wherein the interface coating includes a layer of at least one of the following compositions: 100 wt % Ir; 90-95 wt % Ir, 5-10 wt % Co, 1-2 wt % Al, 1-2 wt % Si; 40-50 wt % Nb, 28-42 wt % Al, 4-15 wt % Cr, 1-2 wt % Si; 90-92 wt % Mo, 4-5 wt % Si, 4-5 wt % B; or 60-80 wt % V, 20-30 wt % Cr, 2-15 wt % Ti.

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: A ceramic article includes a flexible backing selected from paper, woven fabric, non-woven fabric, polymeric films, metal foils, and combinations thereof. A green ceramic layer is on a first side of the flexible backing, wherein the green ceramic layer includes a ceramic material and a polymeric binder. A major surface of the green ceramic layer includes a pattern of features.

Abstract: An article includes an abradable ceramic coating with an arrangement of features selected such that the coating has a porosity of about 5% to about 90%.

Abstract: A ceramic matrix composite component for use in a gas turbine engine and method for making the same are described herein. The component comprising a body and an outer region. The body having a silicon containing ceramic composite. The outer region on an outer surface of the body.

Abstract: The disclosure describes techniques for forming a surface layer of an article including a CMC using a cast. In some examples, the surface layer includes three-dimensional surface features, which may increase adhesion between the CMC and a coating on the CMC. In some examples, the surface layer may include excess material, with or without three-dimensional surface features, which is on the CMC. The excess material may be machined to remove some of the excess material and facilitate conforming the article to dimensional tolerances, e.g., for fitting the article to another component. The excess material may reduce a likelihood that the CMC (e.g., reinforcement material in the CMC) is damaged by the machining.

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 blade and method for producing the blade for a gas turbine engine are described herein. The blade may include a composite airfoil. The airfoil may comprise a ceramic material, and a distal end. A tip may extend from the distal end of the airfoil. The tip of the airfoil may comprise a substantially porous structure and may comprise infiltrated material extending from an airfoil preform to a tip preform to join the airfoil preform and the tip preform.

Abstract: In some examples, an article may include a substrate and a coating on the substrate. In accordance with some of these examples, the coating may include a bond layer and an overlying layer comprising at least one oxide. In some examples, the bond layer comprises silicon metal and at least one of a transition metal carbide, a transition metal boride, or a transition metal nitride.

Abstract: An apparatus includes a ceramic matrix composite (CMC) component and an interface coating on the CMC component, wherein the interface coating includes a layer of at least one of the following compositions: 100 wt % Ir; 90-95 wt % Ir, 5-10 wt % Co, 1-2 wt % Al, 1-2 wt % Si; 40-50 wt % Nb, 28-42 wt % Al, 4-15 wt % Cr, 1-2 wt % Si; 90-92 wt % Mo, 4-5 wt % Si, 4-5 wt % B; or 60-80 wt % V, 20-30 wt % Cr, 2-15 wt % Ti.

Abstract: Ceramic matrix composite materials and processes for making said composite materials are disclosed,

Abstract: A method of making a fiber tow coating is provided. The method includes providing a fiber tow selected from the group consisting of carbon and silicon; and applying an oxide-based fiber interface coating onto the fiber tow using directed vapor deposition or other like deposition method.

Abstract: In some examples, an alloy may include less than 55 atomic percent aluminum; between about 10 and about 25 atomic percent of a platinum group metal; and a balance of nickel; at least one of chromium, silicon, tantalum, or cobalt; a reactive element; and diffusion impurities; where the alloy has a discrete gamma-prime Ni3Al region and a discrete beta NiAl region. In some examples, a coating system may include a substrate; a first layer including gamma-prime Ni3Al; and a second layer including beta NiAl, where the first region and the second region are discrete dual region.

Abstract: An article may include a substrate, a plurality of cooling holes in the substrate, wherein each of the plurality of cooling holes defines substantially the same diameter measured parallel to an outer surface of the substrate, and a coating on the surface of the substrate. In accordance with these examples, the coating covers and substantially blocks a first set of cooling holes from the plurality of cooling holes and leaves a second set of cooling holes from the plurality of cooling holes substantially uncovered. In some examples, an article including a substrate, a plurality of cooling holes in the substrate, and a coating on the substrate. In accordance with these examples, the coating covers and partially occludes each cooling hole of the plurality of cooling holes, and the coating does not extend into any of the plurality of cooling holes.

Abstract: A multilayer liner for a chemical vapor deposition furnace may include a first layer comprising graphite and a second layer comprising a metal or alloy. The first layer may define an internal surface of the multilayer liner, and the multilayer liner may define a substantially closed internal volume. In some examples, the metal or alloy may be the same as a metal or alloy that is in a substrate to be coated within an internal volume of the multilayer liner.

Abstract: In some examples, a coating may include at least one feature that facilitates visual determination of a thickness of the coating. For example, the coating may include a plurality of microspheres disposed at a predetermined depth of the coating. The plurality of microspheres may define a distinct visual characteristic. By inspecting the coating and viewing at least one of the microspheres, the thickness of the coating may be estimated. In some examples, the plurality of microspheres may be embedded in a matrix material, and the distinct visual characteristic of the microspheres may be different than the visual characteristic of the matrix material. In other examples, the at least one feature may include at least one distinct layer in the coating system that includes a distinct visual characteristic, such as a color of the distinct layer.