The present disclosure provides systems and methods for forming a composite structure comprising rotating a base layer of an apparatus for forming the composite structure about an axis of rotation, transferring carbon short fibers from a first vibratory feed ramp onto the base layer in order to form a plurality of fibrous layers in the composite structure, and vibrating the first vibratory feed ramp during the transferring the carbon short fibers. The base layer may comprise an annular shape.

The present disclosure provides a method for coating a composite structure comprising the steps of applying a first slurry of a first phosphate glass composition on an outer surface of the composite structure. The first slurry comprises a first additive including at least one of molybdenum disulfide or tungsten disulfide. The method may further include heating the composite structure to a temperature sufficient to form a base layer adhered to the composite structure.

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.

A friction-braking apparatus for a transportation system, having at least one caliper, at least one piston structured and arranged to move the at least one caliper; and at least one brake pad arranged on the at least one caliper. The at least one caliper is structured and arranged to selectively move the at least one brake pad into engagement with at least one rail of the transportation system.

Systems and methods for forming an oxidation protection system on a composite structure are provided. In various embodiments, an oxidation protection system disposed on a substrate may comprise a boron-silicon-glass layer formed directly on the composite structure. The boron-silicon-glass layer may comprise a boron compound, a silicon compound, and a glass compound.

The present disclosure includes carbon-carbon composite articles having multiphase glass oxidation protection coatings for limiting thermal and/or catalytic oxidation reactions and methods for applying multiphase glass oxidation protection coatings to carbon-carbon composite articles.

A system and method for ceramic doping of carbon fiber materials is disclosed. A carbon fiber preform may be made of carbonized oxidized PAN fibers and may be placed in contact with a nanoparticle suspension having nanoparticles and a dispersion medium. The nanoparticles may impregnate the carbon fiber preform, causing it to become a doped carbon fiber preform. The doped carbon fiber preform may be densified. The doped carbon fiber preform may be densified by conventional CVI processing techniques. The doped carbon fiber preform may be densified by thermal gradient CVI.

A circular air entangling system may comprise a bed plate for receiving fiber layers. An air entangling module may entangle the fiber layers with one another and a fiber packaging apparatus may transport the fiber layers for further processing. In this manner, a fiber preform may be constructed.

A friction material composition that does not contain copper, which has a high environmental load, or containing copper in such small amount as to be not more than 0.5 mass % and that enables decrease in brake vibration in braking at high temperatures when used in a friction material such that for an automobile disc brake pad, is provided. A friction material obtained by molding the friction material composition is also provided. The friction material composition contains a binder, an organic filler, an inorganic filler, and a fibrous base material, and the friction material composition contains no copper as an element or contains not more than 0.5 mass % of copper, and also contains 2 to 5 mass % of steel fibers that have fiber lengths of 2500 μm or less.

A technique of forming a carbon-carbon composite that includes infiltrating a preform comprising carbon fibers or carbon-precursor fibers with a pitch and pyrolyzing the pitch using a controlled pressure and temperature ramp rate to control a growth of optical textures as the pitch is pyrolyzed to a coke matrix. Pyrolyzing the pitch may include initiating pyrolysis of at least some of the pitch at a first pressure less than about 2000 psi and a first temperature ramp rate between about 5 ° C./hr and about 50 ° C./hr to a first target temperature, and pyrolyzing at least some of the pitch at a second pressure greater than 2000 psi and a second temperature ramp rate between about 5 ° C./hr and about 50 ° C./hr to a second target temperature, where the second target temperature is greater than the first target temperature.