A process for manufacturing a porous abradable coating includes: filling a mold with hollow glass or thermosetting polymer beads and a slurry; and sintering heat treatment to obtain a ceramic layer with pores. A maximum sintering temperature of the green body of the ceramic part is either higher than the melting temperature of the hollow glass beads so that at the end of the sintering heat treatment the hollow glass beads are melted, or higher than the decomposition temperature of the hollow thermosetting polymer beads so that at the end of the sintering heat treatment the hollow thermosetting polymer beads are decomposed.

A method of making a ceramic matrix composite according to an exemplary embodiment of this disclosure, among other possible things includes forming a ceramic matrix composite component by infiltrating an array of ceramic-based fibers with a ceramic-based matrix. The array of ceramic-based fibers forms a surface that includes gaps between adjacent ones of the fibers. The method also includes applying a paste including filler particles and filler matrix in a carrier fluid to the surface of the ceramic-based fibers that includes the gaps such that the paste fills the gaps and removing the carrier fluid to leave behind a filler including the filler particles and the filler matrix in the gaps. A ceramic matrix composite component is also disclosed.

A method for processing a component is provided and includes masking a first portion of the component with a maskant. The maskant includes a slurry having a plurality of particles in a fluid carrier. The plurality of particles comprises at least one of silicon, carbon, one or more rare earth disilicates, monosilicates or oxides, and combinations thereof. The method includes depositing a silicon-based coating on a second portion of the component via a chemical vapor deposition process and removing the maskant and any overlying silicon-based coating from the first portion of the component.

Methods for producing oxide/metal composite components for use in high temperature systems, and components produced thereby. The methods use a fluid reactant and a porous preform that contains a solid oxide reactant. The fluid reactant contains yttrium as a displacing metal and the solid oxide reactant of the preform contains niobium oxide, of which niobium cations are displaceable species. The preform is infiltrated with the fluid reactant to react its yttrium with the niobium oxide of the solid oxide reactant and produce an yttria/niobium composite component, during which yttrium at least partially replaces the niobium cations of the solid oxide reactant to produce yttria and niobium metal, which together define a reaction product. The pore volume of the preform is at least partially filled by the reaction product, whose volume is greater than the volume lost by the solid oxide reactant as a result of reacting yttrium and niobium oxide.

An aerospace mirror having a reaction bonded (RB) silicon carbide (SiC) mirror substrate, and a SiC cladding on the RB SiC mirror substrate forming an optical surface on a front side of the aerospace mirror. A method for manufacturing an aerospace mirror comprising obtaining a green mirror preform comprising porous carbon, silicon carbide (SiC), or both, the green mirror preform defining a front side of the aerospace mirror and a back side of the aerospace mirror opposite the front side; removing material from the green mirror preform to form support ribs on the back side; infiltrating the green mirror preform with silicon to create a reaction bonded (RB) SiC mirror substrate from the green mirror preform; forming a mounting interface surface on the back side of the aerospace mirror from the RB SiC mirror substrate, and forming a reflector surface of the RB SiC mirror substrate on the front side of the aerospace mirror. Additionally, the method can comprise cladding the reflector surface of the RB SiC mirror substrate with SiC to form an optical surface of the aerospace mirror.

An aerospace mirror having a reaction bonded (RB) silicon carbide (SiC) mirror substrate, and a SiC cladding on the RB SiC mirror substrate forming an optical surface on a front side of the aerospace mirror. A method for manufacturing an aerospace mirror comprising obtaining a green mirror preform comprising porous carbon, silicon carbide (SiC), or both, the green mirror preform defining a front side of the aerospace mirror and a back side of the aerospace mirror opposite the front side; removing material from the green mirror preform to form support ribs on the back side; infiltrating the green mirror preform with silicon to create a reaction bonded (RB) SiC mirror substrate from the green mirror preform; forming a mounting interface surface on the back side of the aerospace mirror from the RB SiC mirror substrate, and forming a reflector surface of the RB SiC mirror substrate on the front side of the aerospace mirror. Additionally, the method can comprise cladding the reflector surface of the RB SiC mirror substrate with SiC to form an optical surface of the aerospace mirror.

Methods for producing oxide/metal composite components for use in high temperature systems, and components produced thereby. The methods use a fluid reactant and a porous preform that contains a solid oxide reactant. The fluid reactant contains yttrium as a displacing metal and the solid oxide reactant of the preform contains niobium oxide, of which niobium cations are displaceable species. The preform is infiltrated with the fluid reactant to react its yttrium with the niobium oxide of the solid oxide reactant and produce an yttria/niobium composite component, during which yttrium at least partially replaces the niobium cations of the solid oxide reactant to produce yttria and niobium metal, which together define a reaction product. The pore volume of the preform is at least partially filled by the reaction product, whose volume is greater than the volume lost by the solid oxide reactant as a result of reacting yttrium and niobium oxide.

A porous ceramic structure intended to form the reinforcement of a ceramic matrix composite component, the structure having a connected porosity delimited by an internal surface which includes a plurality of first points, each first point being associated with a second point aligned with this first point along a normal to the internal surface taken at the first point, the structure being divisible into a plurality of unit volumes of a size less than or equal to 5 mm3 in each of which: a characteristic pore length, corresponding to the maximum of the distance separating each first point from its associated second point, is less than or equal to 0.5 mm; and a porosity ratio is greater than or equal to 50%.

A method includes forming a crystallized metal carbide undercoat on a surface of a carbon-carbon composite substrate. The method further includes forming an overcoat on a surface of the undercoat. The overcoat includes a plurality of crystallized ultra-high melting point overcoat layers. Each overcoat layer is sequentially formed by applying a mixture to a surface of an underlying layer and heating the mixture. The mixture includes a plurality of ultra-high melting point refractory ceramic particles and a pre-ceramic polymer. The mixture is heated to a heat treatment temperature to pyrolyze the pre-ceramic polymer and form the overcoat layer in an inert atmosphere or under vacuum. As a result, the overcoat layer includes a crystallized ultra-high melting point polymer-derived ceramic matrix that includes the plurality of ultra-high melting point refractory ceramic particles.

This disclosure provides a method of pressure sintering an environmental barrier coating on a surface of a ceramic substrate to form an article. The method includes the steps of etching the surface of the ceramic substrate to texture the surface, disposing an environmental barrier coating on the etched surface of the ceramic substrate wherein the environmental barrier coating includes a rare earth silicate, and pressure sintering the environmental barrier coating on the etched surface of the ceramic substrate in an inert or nitrogen atmosphere at a pressure of greater than atmospheric pressure such that at least a portion of the environmental barrier coating is disposed in the texture of the surface of the ceramic substrate thereby forming the article.