Abstract: A method for repairing an article made of a fiber-reinforced ceramic matrix composite comprises attaching sections of a fiber-reinforced tape to the damaged area and then infiltrating the sections with the ceramic matrix or ceramic matrix precursor material. The material around the damaged area may be removed first to form a depression that is then filled with sections of the fiber-reinforced tape and further infiltrated with the ceramic matrix or ceramic matrix precursor material. The repaired article shows stress-strain curve similar to a defect-free article.

Abstract: In a method of coating a CMC fiber, the fiber is passed through a reaction zone along a path substantially parallel to a longitudinal axis of the zone, a flow of fiber coating reactant is passed though the reaction zone, at least a portion of the flow of reactant is disrupted from a path substantially parallel to the fiber path to create a mixing flow adjacent the fiber. A coating reactor includes a reactor chamber to accommodate a fiber passing along a path substantially parallel to a longitudinal axis of the chamber and a flow of fiber coating reactant. The reactor chamber further includes a flow disrupter located within the reactor chamber to disrupt at least a portion of the flow of reactant from a path substantially parallel to the fiber path to create a mixing flow adjacent the fiber.

Abstract: A method for repairing an article made of a fiber-reinforced ceramic matrix composite comprises attaching sections of a fiber-reinforced tape to the damaged area and then infiltrating the sections with the ceramic matrix or ceramic matrix precursor material. The material around the damaged area may be removed first to form a depression that is then filled with sections of the fiber-reinforced tape and further infiltrated with the ceramic matrix or ceramic matrix precursor material. The repaired article shows stress-strain curve similar to a defect-free article.

Abstract: In a method of coating a CMC fiber, the fiber is passed through a reaction zone along a path substantially parallel to a longitudinal axis of the zone, a flow of fiber coating reactant is passed though the reaction zone, at least a portion of the flow of reactant is disrupted from a path substantially parallel to the fiber path to create a mixing flow adjacent the fiber. A coating reactor includes a reactor chamber to accommodate a fiber passing along a path substantially parallel to a longitudinal axis of the chamber and a flow of fiber coating reactant. The reactor chamber further includes a flow disrupter located within the reactor chamber to disrupt at least a portion of the flow of reactant from a path substantially parallel to the fiber path to create a mixing flow adjacent the fiber.

Abstract: While silicon-containing ceramics or ceramic composites are prone to material loss in combustion gas environments, this invention introduces a method to prevent or greatly reduce the thickness loss by injecting directly an effective amount, generally in the part per million level, of silicon or silicon-containing compounds into the combustion gases.

Abstract: A method for producing shaped articles of ceramic composites provides a high degree of dimensional tolerance to these articles. A fiber preform is disposed on a surface of a stable formed support, a surface of which is formed with a plurality of indentations, such as grooves, slots, or channels. Precursors of ceramic matrix materials are provided to the fiber preform to infiltrate from both sides of the fiber preform. The infiltration is conducted under vacuum at a temperature not much greater than a melting point of the precursors. The melt-infiltrated composite article substantially retains its dimension and shape throughout the fabrication process.

Abstract: In a method of coating a CMC fiber, the fiber is passed through a reaction zone along a path substantially parallel to a longitudinal axis of the zone, a flow of fiber coating reactant is passed though the reaction zone, at least a portion of the flow of reactant is disrupted from a path substantially parallel to the fiber path to create a mixing flow adjacent the fiber. A coating reactor includes a reactor chamber to accommodate a fiber passing along a path substantially parallel to a longitudinal axis of the chamber and a flow of fiber coating reactant. The reactor chamber further includes a flow disrupter located within the reactor chamber to disrupt at least a portion of the flow of reactant from a path substantially parallel to the fiber path to create a mixing flow adjacent the fiber.

Abstract: A porous carbon body is produced from a carbon felt with a low level of metal impurity by forming the body from a carbon felt with a low level of metal impurity, and infiltrating the body with silicon. In another aspect of the invention, an annealing furnace is treated with a halide-containing gas at elevated temperature to scavenge metal impurities. A porous carbon body is then infiltrated with silicon in the annealing furnace.

Abstract: A composite comprised of reinforcement fibers having a continuous coating of a metal nitride wherein the metal is from the group consisting of silicon, aluminum, titanium, zirconium, hafnium, niobium, tantalum, and mixtures thereof, and a molten silicon infiltration formed silicon carbide matrix. The reinforcement fibers are fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A method of forming the composite comprises depositing a continuous coating of the metal nitride on the fibers. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the coated fibers. The mixture is formed into a preform having an open porosity ranging from about 25 volume percent to about 90 volume percent of the preform. The preform is heated in an inert atmosphere or partial vacuum, and infiltrated with molten silicon to produce an infiltrated product having the composition of the composite.

Abstract: A composite comprised of reinforcement fibers having a continuous coating of a metal nitride wherein the metal is from the group consisting of silicon, aluminum, titanium, zirconium, hafnium, niobium, tantalum, and mixtures thereof, and a molten silicon infiltration formed silicon carbide matrix. The reinforcement fibers are fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A method of forming the composite comprises depositing a continuous coating of the metal nitride on the fibers. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the coated fibers. The mixture is formed into a preform having an open porosity ranging from about 25 volume percent to about 90 volume percent of the preform. The preform is heated in an inert atmosphere or partial vacuum, and infiltrated with molten silicon to produce an infiltrated product having the composition of the composite.