Provided is a refractory product which is not impregnated with pitch or the like, wherein it has higher corrosion-erosion resistance and thermal shock resistance as compared to a refractory product subjected to pitch or the like-impregnation treatment. The refractory product which is not impregnated with tar or pitch is characterized in that, in terms of values of physical properties of a sample of the refractory product as measured after heat-treating the sample in a non-oxidizing atmosphere at 1200° C.: an apparent porosity is 7% or less; a total void volume of pores having a pore diameter of 1 μm or less is 80% or more of an integrated void volume of pores of the entire sample of the refractory product; and a gas permeability is 50×10.sup.−17 m.sup.2 or less.

A SiC based sinterable powder mixture comprising, by dried weight of said powder: a) a mineral content comprising—silicon carbide (SiC) particles, —mineral boron compound particles, the powder comprising at least 50% by weight of SiC and the total mineral content of the powder being at least 90% by weight, b) at least a water insoluble carbon-containing source, in particular a carbon containing resin, the powder comprising at least 1% by weight, and preferably less than 10% by weight, of said water insoluble carbon-containing source, wherein the average particle size of said sinterable powder is comprised between 0.5 to 2.0 micrometers.

A method for manufacturing ceramic matrix composites (CMC) and CMCs made by the method are disclosed. The method can be a manual process or an automated process, such as using a robotic system, that is used for controlled delivery of ceramic particles in a CMC fabric. The method includes identifying voids present between adjacent tows of the CMC fabric and dispensing ceramic particles into the voids. Applying the ceramic particles in the center of the voids reduces the size and volume fraction of the voids/defects, improving the homogeneity of surface texture of the preform, homogeneity of microstructure, and part model shape conformity. The method for manufacturing CMCs creates CMCs having a homogenous distribution of small pores after matrix formation that improves the interlaminar mechanical and thermal properties of the CMCs.

A method of preparing a woven ceramic fabric for use in a ceramic matrix composite includes transforming a woven fabric sheet having a first tow architecture into a separated woven fabric sheet having a second tow architecture, the first tow architecture including a plurality of warp tows and a plurality of weft tows, and the second tow architecture including a plurality of warp subtows and/or a plurality of weft subtows. Transforming the woven fabric sheet includes separating at least some of the plurality of warp tows and/or the plurality of weft tows into a greater number of corresponding warp subtows and/or weft subtows, respectively, such that second tow architecture includes more warp subtows and/or weft subtows than the first tow architecture comprises warp tows and weft tows, and wherein each of the warp subtows and/or weft subtows includes fewer filaments than corresponding warp tow and/or weft tow. Each of the plurality of warp subtows and/or weft subtows is spaced apart from the closest adjacent warp subtow and/or weft subtow, respectively, a distance of 25 to 230 microns.

Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, the oxidation protection system comprises a boron-glass layer formed on the composite substrate and a silicon-glass layer formed over the boron-glass layer. Each of the boron-glass layer and the silicon-glass layer includes a glass former.

A method of separating a mixture of used refractory components of different chemistry types obtained from a demolished refractory includes hydrating the mixture of refractory components to destructively hydrate at least some components of the mixture of refractory components, and separating, based on size, the at least some components from other components of the mixture of refractory components.

Provided is a ZrO.sub.2—CaO—C based refractory material which is capable of maintaining high adhesion resistance over a long period of time, while exhibiting significant slaking resistance, and suppressing self-fluxing, i.e., exhibiting corrosion-erosion resistance. The refractory material comprises a CaO—ZrO.sub.2 composition containing a CaO component in an amount of 40% by mass to 60% by mass, wherein a mass ratio of the CaO component to a ZrO.sub.2 component is 0.67 to 1.5, and wherein the CaO—ZrO.sub.2 composition includes a eutectic microstructure of CaO crystals and CaZrO.sub.3 crystals, wherein a width of each of the CaO crystals observable in a cross-sectional microstructure is 50 μm or less.

A method of forming a ceramic matrix composite component includes forming a fiber preform, the fiber preform including a plurality of ceramic fiber plies, a non-reduced fiber region having an areal weight, and a reduced fiber region characterized by a reduced areal weight less than the areal weight of the non-reduced fiber region by at least 5 percent. The method further includes selectively applying ceramic particles to the reduced fiber region in such manner as to avoid applying the ceramic particles to the non-reduced fiber region, and subsequently densifying the preform.

The present disclosure relates to a ceramic component including a boron carbide, wherein a difference of a first residual stress measured at a first spot on a surface of the ceramic component and a second residual stress measured at a second spot on the surface having different distance from a center of the surface than the first spot is −600 to +600 MPa.

A ceramic component included in a plasma etching apparatus, wherein a surface of the ceramic component may include a base material and a composite material disposed in contact with the base material, wherein a resistivity of the ceramic component may be 10.sup.−1 Ω.Math.cm to 20 Ω.Math.cm, and wherein the base material may include a first boron carbide-based material and the composite material may include at least one selected from the group consisting of a second boron carbide-based material, a carbon-based material, and combinations thereof, is disclosed.