A boundary layer turbine (BLT) engine has a housing formed by an outer cylinder a first and a second faceplate, a turbine shaft through the faceplates, a stack of alternating disks and spacers with central holes joined to the turbine shaft leaving an outer combustion zone, an air inlet through the first faceplate, an exhaust port through the second faceplate, a fuel port through the outer cylinder, and an ignition device communicating with the combustion zone. The disks and spacers have openings forming separate intake and exhaust channels parallel to the turbine shaft, one channel channeling air from the air inlet port to spaces between disks, and the other channel channeling exhaust from the combustion zone through the exhaust channel to the exhaust port. Fuel is injected into the combustion zone, the air fuel mixture is ignited, and exhaust products impart torque to the turbine shaft by boundary layer friction.

An article includes a substrate and a barrier layer on the substrate. The barrier layer includes a matrix, diffusive particles dispersed in the matrix, and gettering particles dispersed in the matrix. The gettering particles include at least one alloyed metal silicide. A composite material and a method of fabricating an article are also disclosed.

A method for repairing composite components includes positioning repair material within a repair region of a composite component formed of a composite material. Furthermore, the method includes filling a feature defined by the composite component with a filler material, with the filler material being a precursor to the composite material. Additionally, after filling the feature with the filler material, the method includes infiltrating the composite component with an infiltrant to densify the repair region and the filler material such that the feature is filled with new material.

An article includes a ceramic-based substrate and a barrier layer on the ceramic-based substrate. The barrier layer includes a matrix, diffusive particles, and gettering particles. The gettering particles include at least one of non-gas-evolving particles and porous particles. An article and a method are also disclosed.

Methods for forming sintered-bonded high temperature coatings over ceramic turbomachine components are provided, as are ceramic turbomachine components having such high temperature coatings formed thereover. In one embodiment, the method includes the step or process of removing a surface oxide layer from the ceramic component body of a turbomachine component to expose a treated surface of the ceramic component body. A first layer of coating precursor material, which has a solids content composed predominately of at least one rare earth silicate by weight percentage, is applied to the treated surface. The first layer of the coating precursor material is then heat treated to sinter the solids content and form a first sintered coating layer bonded to the treated surface. The steps of applying and sintering the coating precursor may be repeated, as desired, to build a sintered coating body to a desired thickness over the ceramic component body.

A gas turbine engine component includes a ceramic matrix composite (CMC) body that includes an interior surface that defines a blind cavity. A barrier coating is disposed on an exterior of the CMC body. A ceramic body in the blind cavity lines at least a portion of the interior surface of the CMC body. The ceramic body defines an open, interconnected network of pores.

Laminate components and methods for forming the same are provided. In one exemplary aspect, one or more features are laser cut into or along a laminate component or laminate sections thereof. The features are laser cut into or along the laminate component in an atmosphere. In this manner, and oxide layer is formed on the laser cut surfaces of the future. The features are laser cut into or along the laminate component or laminate sections thereof prior to an infiltration process, such as melt infiltration or chemical vapor infiltration. Accordingly, when the laminate component is infiltrated with an infiltration material, the infiltration material is prevented from infiltrating therethrough.

A coated turbomachine component includes a ceramic component body having a principal surface. The component includes a high temperature coating. The high temperature coating includes a sintered coating body bonded directly to and intimately contacting the principal surface of the ceramic component body. The sintered coating body has a minimum porosity adjacent the principal surface and a maximum porosity at a location further from the principal surface, as taken along an axis orthogonal to the principal surface.

A method of processing a CMC component includes applying a surface formulation comprising a resin and/or a preceramic polymer to a fiber preform. The surface formulation is cured to form a surface coating, which is then pyrolyzed to convert the resin to carbon and/or the preceramic polymer to silicon carbide. After pyrolysis, the fiber preform is infiltrated with a melt comprising silicon to form a CMC component. During melt infiltration, the carbon reacts with the silicon to form silicon carbide, and the silicon carbide prevents unreacted silicon from accessing a surface region of the CMC component. Thus, after melt infiltration, a concentration of free silicon in the surface region is a low amount of about 5 vol. % or less. Upon assembling the CMC component with a metal component, diffusion between the components is inhibited or prevented by the low amount of free silicon in the surface region.

In some examples, an article includes a ceramic or a ceramic or ceramic matrix composite (CMC) substrate; and an abradable coating on the CMC substrate. The abradable coating includes a plurality of first rare earth (RE) silicate layers in an alternating arrangement with a plurality of second RE silicate layers, wherein the first RE silicate layers include a rare earth monosilicate and the second RE silicate layers include a rare earth disilicate, and wherein the first RE silicate layers include a greater concentration of the rare earth monosilicate than the second RE silicate layers.