A cBN sintered body has 40%-85% cBN by volume and 15% to 60% binder phase by volume. and inevitable impurities. The binder phase has an Al compound including Al and at least one element selected from N, O and B, and a Zr compound including Zr and at least one element selected from C, N, O and B. The Zr compound includes ZrO, or ZrO and ZrO.sub.2. In an X-ray diffraction, where a peak intensity of a (111) plane of the ZrO is I.sub.1, a peak intensity of a (101) plane of tetragonal ZrO.sub.2 is I.sub.2t and a peak intensity of a (111) plane of cubic ZrO.sub.2 is I.sub.2c, a ratio of the intensity of I.sub.1 to total intensities of I.sub.1, I.sub.2t and I.sub.2c is 0.6-1.0, and an average grain size of the Al compound is 80 nm-300 nm.

A method for producing a ceramic matrix composite component is disclosed. The method includes providing a plurality of first ceramic fiber plies including a plurality of interconnected tows and a plurality of first pores positioned between adjacent tows. The method includes applying a plurality of first ceramic particles within the plurality of first pores. Next, the method includes applying a plurality of second ceramic fiber plies onto an outer surface of the plurality of first ceramic fiber plies. The second ceramic fiber plies include a plurality of interconnected tows and a plurality of second pores positioned between adjacent tows. The method then includes applying a plurality of second ceramic particles within the plurality of second pores. Further, the plurality of second ceramic particles are larger than the plurality of first ceramic particles. Lastly, the method includes densifying the ceramic matrix composite preform to form the ceramic matrix composite component.

Disclosed herein is a ceramic matrix composite comprising a preform comprising a plurality of plies; a ceramic matrix encompassing the plies and distributed through the plies; and thermally conducting particles distributed through the ceramic matrix. Disclosed herein is a method comprising distributing thermally conducting particles between plies in a preform; infiltrating chemical vapors of a ceramic precursor into the plies; and reacting the ceramic precursor to form a matrix.

Ultra-high temperature carbide (UHTC) foams and methods of fabricating and using the same are provided. The UHTC foams are produced in a three-step process, including UHTC slurry preparation, freeze-drying, and spark plasma sintering (SPS). The fabrication methods allow for the production of any kind of single- or multi-component UHTC foam, while also providing flexibility in the shape and size of the UHTC foams to produce near-net-shape components.

Provided is a crystalline silicon carbide fiber containing silicon carbide, boron nitride, and zirconium carbide and having a content of Si of 64% by weight or more and a content of C of 28% by weight or more, in which the average particle size of SiC crystal grains is 100 nm or more.

The present invention provides a novel silicon carbide fiber reinforced silicon carbide composite material, which is a composite material of SiC fibers and SiC ceramics with improved toughness, that can be produced with high yield by a relatively simple production step without complex production steps such as a step of oxidation-resistant coating or an advanced interface control step.

The silicon carbide fiber reinforced silicon carbide composite material comprising a multiphase matrix containing a silicon carbide phase and a phase comprising a substance having low reactivity with respect to silicon carbide; and silicon carbide fibers disposed in the matrix can be obtained by a production step suitable for mass production. The composite material ensures greatly improved fracture toughness while maintaining the excellent properties of SiC ceramics.

In one aspect, sintered ceramic bodies are described herein which, in some embodiments, demonstrate improved resistance to wear and enhanced cutting lifetimes. For example, a sintered ceramic body comprises tungsten carbide (WC) in an amount of 40-95 weight percent, alumina in an amount of 5-30 weight percent and ditungsten carbide (W.sub.2C) in an amount of at least 1 weight percent.

The disclosure describes techniques for infiltrating a porous preform with a slurry to form an infiltrated-preform, where the slurry includes a plurality of solid particles, where the plurality of solid particles include a plurality of fine ceramic particles defining an average fine particle diameter, a plurality of coarse ceramic particles defining an average coarse particle diameter, and a plurality of diamond particles, where the average fine particle diameter is less than the average coarse particle diameter, and infiltrating the infiltrated-preform with a molten metal infiltrant to form a ceramic matrix composite (CMC) article.

A refractory object can include at least 10 wt % Al.sub.2O.sub.3. Further, the refractory object may contain less than approximately 6 wt % SiO.sub.2 or may include a dopant that includes an oxide of Ti, Mg, Ta, Nb, or any combination thereof. In an embodiment, at least approximately 1% of the Al.sub.2O.sub.3 in the refractory object can be provided as reactive Al.sub.2O.sub.3. In another embodiment, the refractory object may have a density of at least approximately 3.55 g/cc, a corrosion rate of no greater than approximately 2.69 mm/year, or any combination of the foregoing. In a particular embodiment, the refractory object can be used to form an Al—Si—Mg glass sheet. In an embodiment, the refractory object may be formed by a process using a compound of Ti, Mg, Ta, Nb, or any combination thereof.

The present invention provides a welding tool member for friction stir welding comprising a silicon nitride sintered body, wherein the silicon nitride sintered body includes an additive component other than silicon nitride in a content of 15% by mass or less, and the additive component includes three or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. It is preferable that the content of the additive component is 3% by mass or more and 12.5% by mass or less. It is also preferable that the additive component includes four or more elements selected from Y, Al, Mg, Si, Ti, Hf, Mo and C. Due to above structure, there can be provided a welding tool member for friction stir welding having a high durability.