A method for densifying porous annular substrates by chemical vapor infiltration, includes providing a plurality of unit modules including a support tray on which substrates are stacked, the support tray including a gas intake opening extended by an injection tube disposed in an internal volume formed by the central passages of the stacked substrates, the injection tube including gas injection orifices opening into the internal volume, forming stacks of unit modules in the enclosure of a densification furnace and injecting, into the stacks of unit modules, a gas phase including a gas precursor of a matrix material to be deposited within the porosity of the substrates.

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 at least one silicon carbide fibre, the method including a) formation of a silica layer at the surface of a silicon carbide fibre having an oxygen content less than or equal to 1% in atomic percentage, the silica layer being formed by contacting this fibre with an oxidizing medium having a temperature greater than or equal to 50° C. and pressure greater than or equal to 1 MPa, and b) removal of the silica layer formed by hydrothermal treatment of the fibre obtained after implementation of step a) in which the fibre is treated with water at a pressure between saturating vapour pressure and 30 MPa and at a temperature less than or equal to 400° C.

A ceramic matrix composite includes a ceramic matrix, fibers embedded in the ceramic matrix, and an interfacial coating system on each of the fibers. The interfacial coating system includes alternating layers of boron nitride layers of individual thicknesses of about 50 nanometers to 200 nanometers and carbon layers of individual thicknesses of less than 5 nanometers.

This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

A method for densifying one or more porous substrates with pyrolytic carbon by chemical vapour infiltration, includes admitting, at the inlet of the densification furnace, a reactive gaseous phase including at least one pyrolytic carbon precursor; reacting at least a fraction of the reactive gaseous phase with the porous substrate or substrates; extracting, at the outlet of the densification furnace, gaseous effluents originating from the reactive gaseous phase; reintroducing, with the reactive gaseous phase admitted at the inlet of the densification furnace, at least a fraction of the gaseous effluents extracted at the outlet of the furnace, wherein the fraction of the gaseous effluents introduced with the reactive gaseous phase includes at least one polyaromatic hydrocarbon compound.

The present invention describes various aspects of an inexpensive, renewable and sustainable particulate material system which is basically composed of one or more carbon precursor materials and other powder-based constituents. There is also an in-detail description of the composition of the preferred particulate material system and steps involved in manufacturing high-performance carbon composite articles using commercial binder jetting powder-based 3D printers. The preferred particulate material system composition of the present invention can be equal in performance to typical binder jetting 3D printing powders but much less expensive.

A ceramic matrix composite has fibers, a ceramic matrix bonded to the fibers, and ceramic particles, distributed throughout the matrix. A method includes mixing a high char ceramic resin precursor with ceramic particles, adding a catalyst to create a mixture, heating the mixture to produce functionalized ceramic particles, and cooling the mixture to produce a resin having functionalized particles.

A method for making a carbon carbon, carbon ceramic matrix, or carbon silica composite, comprising melt processing a resin comprising a polyaryletherketone (PAEK) and at least one reinforcing additive to make a precursor part, pyrolyzing the precursor part to make a pyrolyzed part, infusing a liquid second resin into the pyrolyzed part to make an infused part, and pyrolyzing the infused part. Other methods comprise processing aligned reinforcing additives and a resin comprising a PAEK to make an aligned reinforcing additives PAEK, aligned 1-2 dimensional flake material, or aligned 1-2 dimensional platelet material, to create a fabric, prepreg or tape comprising the aligned reinforcing additives and impregnated PAEK. Other methods comprise impregnating continuous fiber tape or fabric with a resin comprising PAEK and at least one reinforcing additive or co-weaving a continuous fiber or fabric with a PAEK fiber comprising PAEK and at least one reinforcing additive.

A method of fabricating a brake component made from a ceramic matrix composite is disclosed. In various embodiments, the method includes infiltrating a carbon fabric with a slurry containing a ceramic powder and a sintering aid; laying up the carbon fabric in a desired geometry to form a raw component; warm pressing the raw component to form a green component; and sintering the green component via a spark plasma sintering process to form a sintered component.