A ceramic matrix composite article, method for forming the article, and perforated ply which may be incorporated therein are disclosed. The article includes at least one shell ply forming an exterior wall having first and second portions and defining a plenum. An annular brace formed of at least one structural support ply is disposed within the plenum, including a first integral portion integral with and part of the first portion of the exterior wall, a first curved portion extending from the first integral portion and curving across the article plenum to the second portion of the exterior wall, a second integral portion integral with and part of the second portion of the exterior wall, a second curved portion extending from the second integral portion and curving across the article plenum to the first curved portion, and an overlap in which the first and second curved portions are integral.

A method to produce a ceramic matrix composite with controlled surface characteristics includes: applying a scrim ply to a surface of a fiber preform, where the fiber preform includes silicon carbide fibers coated with boron nitride; infiltrating the fiber preform and the scrim ply with a slurry, thereby forming an impregnated ply on an impregnated fiber preform; infiltrating the impregnated fiber preform and the impregnated ply with a melt comprising silicon, and then cooling, thereby forming a ceramic matrix composite having a ceramic surface layer thereon, where the ceramic surface layer has a predetermined thickness and is devoid of boron; machining or grit blasting the ceramic surface layer to form an intermediate layer suitable for coating; and depositing an environmental barrier coating on the intermediate layer. Thus, a ceramic matrix composite coated with the environmental barrier coating is formed with the intermediate layer in between.

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.

A gas turbine engine component includes a gas turbine engine component body formed of a ceramic matrix composite material having at least one fastener integrally formed with the gas turbine engine component body as a single-piece structure. The gas turbine engine component body initially comprises a rigidized preform structure formed from a polymer based material. The at least one fastener connects the gas turbine engine component body to an engine support structure.

A spinel-reinforced magnesium oxide-based foam ceramic filter that is obtained by coating onto a polyurethane foam carrier a slurry of light calcined magnesium oxide-based ceramic comprising a nanometer lanthanum oxide sintering aid, and then drying and sintering. A method for preparing the foam ceramic filter comprising: 1) preparing a ceramic slurry having a solid content of 60%-70% by dosing 15%-25% by mass of a nanometer alumina sol, 0.8%-1.5% by mass of a rheological agent, and the balance magnesium oxide ceramic powder comprising a nanometer lanthanum oxide sintering aid, and then adding absolute ethanol and ball milling to mix until uniform; 2) soaking a polyurethane foam template into the ceramic slurry, squeezing by a roller press the polyurethane foam template to remove redundant slurry therein to make a biscuit, and then removing the ethanol solvent in a ventilation chamber at a temperature of 40° C.-50° C. to dry the biscuit; 3) putting the dried biscuit into a sintering furnace, elevating the temperature to 1350° C.-1550° C. and performing a high temperature sintering, cooling to the room temperature with the furnace to obtain the magnesium oxide-based ceramic foam filter.

A system and method for forming a porous ceramic preform is provided. The method may include forming a stacked powder structure including a binder layer and a powder layer on the binder layer. The binder layer may be formed by depositing a binder with a spray nozzle on a substrate. The powder layer may be formed by depositing a powder on the binder layer. The porous ceramic preform may be formed by heating the stacked powder structure to pyrolyze the binder. The porous ceramic preform is configured to be infiltrated by a molten material. The substrate may comprise a ceramic fiber preform. After melt infiltration of the porous ceramic preform and the ceramic fiber preform, a densified ceramic feature having a predetermined geometry may be formed on a ceramic matrix composite (CMC) component.

A method for manufacturing an electrostatic chuck with multiple chucking electrodes made of ceramic pieces using metallic aluminum as the joining. The aluminum may be placed between two pieces and the assembly may be heated in the range of 770 C to 1200 C. The joining atmosphere may be non-oxygenated. After joining the exclusions in the electrode pattern may be machined by also machining through one of the plate layers. The machined exclusion slots may then be filled with epoxy or other material. An electrostatic chuck or other structure manufactured according to such methods.

A method for manufacturing an electrostatic chuck with multiple chucking electrodes made of ceramic pieces using metallic aluminum as the joining. The aluminum may be placed between two pieces and the assembly may be heated in the range of 770 C to 1200 C. The joining atmosphere may be non-oxygenated. After joining the exclusions in the electrode pattern may be machined by also machining through one of the plate layers. The machined exclusion slots may then be filled with epoxy or other material. An electrostatic chuck or other structure manufactured according to such methods.

A CMC ply assembly is disclosed including at least one matrix ply interspersed amongst a plurality of CMC plies. Each of the plurality of CMC plies includes a first matrix and a plurality of ceramic fibers. The at least one matrix ply includes a second matrix and is essentially free of ceramic fibers. The plurality of CMC plies and the at least one matrix ply are arranged in an undensified ply stack having an article conformation. A CMC article is disclosed including a plurality of densified CMC plies and at least one densified matrix ply interspersed amongst the plurality of densified CMC plies. A method for forming the CMC article is disclosed including forming, carburizing, infusing a melt infiltration agent into, and densifying the CMC ply assembly. The melt infiltration agent infuses more completely through the at least one matrix ply than through the plurality of CMC plies.

A method of producing a ceramic matrix composite including a protective ceramic coating thereon comprises applying a surface slurry onto an outer surface of an impregnated fiber preform. The surface slurry includes particulate ceramic solids dispersed in a flowable preceramic polymer comprising silicon, and the impregnated fiber preform comprises a framework of ceramic fibers loaded with particulate matter. The flowable preceramic polymer is cured, thereby forming on the outer surface a composite layer comprising a cured preceramic polymer with the particulate ceramic solids dispersed therein. The cured preceramic polymer is then pyrolyzed to form a porous ceramic layer comprising silicon carbide, and the impregnated fiber preform and the porous ceramic layer are infiltrated with a molten material comprising silicon. After infiltration, the molten material is cooled to form a ceramic matrix composite body with a protective ceramic coating thereon.