A method for coating fibres includes coating short fibres having an average length less than or equal to 5 mm by chemical vapour deposition in a fluidised bed, the short fibres treated being made of ceramic material or carbon and being mixed with spacer particles distinct from the short fibres, the spacer particles having an average diameter greater than or equal to 20 μm.

A silicon-containing oxide-coated aluminum nitride particle including an aluminum nitride particle and a silicon-containing oxide coating covering the surface of the aluminum nitride particle. The content of carbon atoms is less than 1000 ppm by mass, and an Si/Al atom ratio of the surface as measured by AES analysis is 0.29 or more and 5.0 or less. In another aspect, the coverage of the silicon-containing oxide coating covering the surface of the aluminum nitride particle as measured by LEIS analysis is 15% or more and 100% or less.

Disclosed is a coated ceramic fiber including a silicon carbide coating layer adjacent to the ceramic fiber and a silicon dioxide coating layer adjacent to the silicon carbide coating layer, wherein the silicon dioxide coating layer forms micro cracks after a crystal structure transformation. The coated ceramic fiber may be included in a composite material having a ceramic matrix.

An automated preparation method of a SiC.sub.f/SiC composite flame tube, comprising the following steps: preparing an interface layer for a SiC fiber by a chemical vapor infiltration process, and obtaining the SiC fiber with a continuous interface layer; laying a unidirectional tape on the SiC fiber with the continuous interface layer and winding the SiC fiber with the continuous interface layer to form and obtaining a preform of a net size molding according to a fiber volume and a fiber orientation obtained in a simulation calculation; and adopting a reactive melt infiltration process and the chemical vapor infiltration process successively for a densification and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way. The SiC.sub.f/SiC composite flame tube prepared by the present disclosure not only has a high temperature resistance, but also has a low thermal expansion coefficient, high thermal conductivity and high thermal shock resistance.

A method of treating silicon carbide fibers comprises phosphating heat treatment in a reactive gas so as to form a coating around each fiber for protection against oxidation. The coating comprises a surface layer of silicon pyrophosphate crystals and at least one underlying bilayer system comprising a layer of a phosphosilicate glass and a layer of microporous carbon.

A method of making a ceramic matrix composite that exhibits chemical resistance has been developed. The method comprises depositing a compliant layer comprising boron nitride, silicon-doped boron nitride, and/or pyrolytic carbon on silicon carbide fibers, depositing a barrier layer having a high contact angle with molten silicon on the compliant layer, and depositing a wetting layer comprising silicon carbide, boron carbide, and/or pyrolytic carbon on the barrier layer. After depositing the wetting layer, a fiber preform comprising the silicon carbide fibers is infiltrated with a slurry. After slurry infiltration, the fiber preform is infiltrated with a melt comprising silicon, and then the melt is cooled, thereby forming a ceramic matrix composite.

A method of making a ceramic matrix composite that exhibits moisture and environmental resistance has been developed. The method includes depositing a diffusion barrier layer comprising boron nitride on silicon carbide fibers and depositing a moisture-tolerant layer comprising silicon-doped boron nitride on the diffusion barrier layer, where a thickness of the moisture-tolerant layer is from about 3 to about 300 times a thickness of the diffusion barrier layer. Thus, a compliant multilayer including the moisture-tolerant layer and the diffusion barrier layer is formed. A wetting layer comprising silicon carbide, boron carbide, and/or pyrolytic carbon is deposited on the compliant multilayer layer. After depositing the wetting layer, a fiber preform comprising the silicon carbide fibers is infiltrated with a slurry. After slurry infiltration, the fiber preform is infiltrated with a melt comprising silicon and then the melt is cooled, thereby forming a ceramic matrix composite.

A method of depositing silicon carbide on a preform to form a ceramic matrix composite comprises placing the preform into a reaction vessel, removing air from the reaction vessel and backfilling the reaction vessel with an inert gas to an operating pressure. The reaction vessel and the preform are heated to an operating temperature. A carrier gas and precursor materials are heated to a preheat temperature outside of the reaction vessel. The carrier gas and the precursor materials are introduced to the reaction vessel in a specified ratio. Off gasses, the precursor materials that are unspent, and the carrier gas are removed from the reaction vessel to maintain the specified ratio of the precursor materials in the reaction vessel.

Thermoelectric (TE) nanocomposite material that includes at least one component consisting of nanocrystals. A TE nanocomposite material in accordance with the present invention can include, but is not limited to, multiple nanocrystalline structures, nanocrystal networks or partial networks, or multi-component materials, with some components forming connected interpenetrating networks including nanocrystalline networks. The TE nanocomposite material can be in the form of a bulk solid having semiconductor nanocrystallites that form an electrically conductive network within the material. In other embodiments, the TE nanocomposite material can be a nanocomposite thermoelectric material having one network of p-type or n-type semiconductor domains and a low thermal conductivity semiconductor or dielectric network or domains separating the p-type or n-type domains that provides efficient phonon scattering to reduce thermal conductivity while maintaining the electrical properties of the p-type or n-type semiconductor.

Methods of forming nanoceramic materials and components. The methods may include performing atomic layer deposition to form a plurality of nanoparticles, including forming a thin film coating over core particles, or sintering the nanoparticles in a mold. The nanoparticles can include a first material selected from a rare earth metal-containing oxide, a rare earth metal-containing fluoride, a rare earth metal-containing oxyfluoride or combinations thereof.