Abstract: In some examples, a technique for forming a partially densified preform including ceramic particles may include mixing a densifying agent with metal oxide particles or metal oxide precursor to form a blended densifying agent, infiltrating the blended densifying agent in to a porous preform, pyrolyzing the infiltrated preform to convert the densifying agent to carbon and form a partially densified preform, and heat treating the partially densified preform to react at least some of the carbon with the metal oxide particles to form ceramic particles. Composite materials formed from porous preforms in which a blended densifying agent is disposed in pores of the preform are also described.

Abstract: In some examples, a technique for forming a partially densified preform including ceramic particles may include mixing a densifying agent with metal oxide particles or metal oxide precursor to form a blended densifying agent, infiltrating the blended densifying agent in to a porous preform, pyrolyzing the infiltrated preform to convert the densifying agent to carbon and form a partially densified preform, and heat treating the partially densified preform to react at least some of the carbon with the metal oxide particles to form ceramic particles. Composite materials formed from porous preforms in which a blended densifying agent is disposed in pores of the preform are also described.

Abstract: Method of chemical vapor infiltration of a deposable carbon material into a porous carbon fiber preform in order to densify the carbon fiber preform. The method includes the steps of: situating the porous carbon fiber preform in the reaction zone; providing a linear flow of a reactant gas comprising deposable carbon material in the reaction zone at an initial reaction pressure of at most 50 torr to produce deposition of the deposable carbon material into the preform; and adjusting the pressure of the gas to reaction pressures lower than said initial reaction pressure while deposable carbon material continues to be deposited into the porous carbon fiber preform. This method enables attainment of a target increased density in a carbon fiber preform much more quickly than known processes. A programmed pressure swing throughout the CVI/CVD run may be set in order to provide a linear increase in density.

Abstract: A method and brake disc assembly to utilize worn refurbished brake material is disclosed. The method discloses the use of a brake disc for braking and the subsequent machining or refurbishment of the brake disc so that the brake disc can be used for three tours of braking to increase the utilization of the brake material.

Abstract: A gas preheater (10) that includes an exit plate (20) having first and second sides (22, 24) and a plurality of through holes (26) and at least one body (34) mounted adjacent the first side (22), the at least one body (34) having a first end (36) and a second end (38), the second end (38) located between the body first end (36) and the exit plate first side (22), at least one sidewall (40) connecting the first and second ends (36, 38), a body opening (42) in the first end (36) extending into the body (34) and defining a body inner wall (44), and a plurality of passages (46) extending between the at least one sidewall (40) and the body inner wall (44).

Abstract: Apparatus including a carbon-carbon composite pressure plate (32, 42) having a friction surface (33, 43) on one side thereof, a non-friction surface (37, 47) on the opposite side thereof, and a body (39, 49) between said surfaces. A wear pin housing (36, 46) containing a wear pin retainer (35, 45) is located in the pressure plate body (39, 49), the wear pin housing opening to the non-friction surface (37, 47) but not opening to the friction surface (33, 43). A wear pin (31), preferably made of carbon-carbon composite material, is located in the wear pin retainer (35, 45). The wear pin retainer (35, 45), which may be made of carbon-carbon composite material, is held in place in the wear pin housing (36, 46) by the interaction of threading in the wear pin housing (36, 36) and threading in the wear pin retainer (35, 45) and optionally also by a carbonizable resin adhesive located between the wear pin housing threading and the wear pin retainer threading.

Abstract: An improved aircraft brake system and method of manufacturing the same. The system comprises a rotatable wheel axle, a heat treated stationary carbon disc secured to the wheel axle and a rotating carbon disc heat treated to a temperature substantially higher than the heat treating temperature of the stationary carbon disc and rotatably supported relative to the wheel axle and arranged parallel to the stationary carbon disc. The method comprises heat treating the rotating and stationary carbon discs to different final temperatures prior to assembly of the aircraft brake system.

Abstract: A template (10) configured for use with an annular preform (26) having a periphery (32) and an inner opening (34), the template (10) having an annular body with an outer periphery (16) and an inner opening (18) and a plurality of spacer openings (12) through its body each for receiving a spacer (25), one of the template inner opening (18) and the template outer periphery (16) having a width equal to the width of the preform inner opening (34) or the preform outer periphery (32). Also a method for densifying preforms that includes a step of positioning spacers using a template.

Abstract: Method of manufacturing carbon-carbon composite brake disc by: (a) providing textile-based preform in shape of annular brake disc, the preform having a volume 30% or more greater than the volume of the brake disc to be manufactured; (b) subjecting the preform to a first CVD processing for not more than 7.5 days to density it to not more than 1.0 g/cc; (c) machining the densified preform to a shape having a volume no more than 15% greater than the volume of the carbon-carbon composite brake disc to be manufactured: and (d) subjecting the preform to one or two additional cycles of CVD processing, to further densify it to a density of more than 1.7 g/cc. The preform is then machined to provide the carbon-carbon composite brake disc. The total CVD processing time in steps (b) and (c) is no longer than about 32.5 days.

Abstract: A hearth plate (30) includes a flat rectangular plate (32) having a top surface (34), a bottom surface (36), and a plurality of through openings (38) between the top surface (34) and bottom surface (36), four support walls (40) having top edges connected around the periphery of the bottom surface (36) and bottom edges and a bottom wall (42) connected to the bottom edges of the support walls (40). A preheater structure (46) is mounted in the space (44) defined by the four support walls (40), flat rectangular plate (32) and bottom wall (42), and a rectangular enclosure comprising four interconnected graphite walls (54, 56, 58) is mounted around the peripheral edge of the top surface (34) to define a processing volume for receiving objects (50) to be processed. A graphite lid (72) is removably supported by the rectangular enclosure.

Abstract: Method of chemical vapor infiltration of a deposable carbon material into a porous carbon fiber preform in order to densify the carbon fiber preform. The method includes the steps of: situating the porous carbon fiber preform in the reaction zone; providing a linear flow of a reactant gas comprising deposable carbon material in the reaction zone at an initial reaction pressure of at most 50 torr to produce deposition of the deposable carbon material into the preform; and adjusting the pressure of the gas to reaction pressures lower than said initial reaction pressure while deposable carbon material continues to be deposited into the porous carbon fiber preform. This method enables attainment of a target increased density in a carbon fiber preform much more quickly than known processes. A programmed pressure swing throughout the CVI/CVD run may be set in order to provide a linear increase in density.

Abstract: The present invention relates to annular drive inserts which are placed within an annular opening within the brake disk. Preferably the annular drive inserts comprise carbon-carbon composite which has been treated with antioxidant. In a highly preferred embodiment the treatment is accomplished by vacuum impregnation. The antioxidant generally comprises a standard phosphoric acid based solution. This invention solves a need in the art for annular drive inserts that have improved resistance to oxidation and strength.

Abstract: Method for densifying a porous carbon preform (5). The method includes the steps of: (a) providing the apparatus (11); (b) charging the apparatus (11) with a plurality of stacks of annular porous carbon preforms (5), the preforms being separated from one another by spacers (15); (c) locating the charged apparatus (11) in a furnace at a temperature in the range of 950-1100° C. and a pressure in the range of 5-40 torr; and (d) circulating a natural gas reactant blended with up to 15% propane through the apparatus for a period of from 150 to 900 hours. Carbon-carbon composite preforms made by this method may be configured as aircraft landing system brake discs or racing car brake discs.

Abstract: The present invention pertains to carbon-carbon composites what are reinforced with PAN-based carbon fibers and which have an all pyrocarbon matrix deposited via chemical vapor infiltration and/or chemical vapor deposition. The uniquely low wear life of the C—C composites of this invention is achieved via a high initial heat treatment of the preforms made from PAN-based carbon fibers—providing a high modulus to the fibers, making them less abrasive—followed by CVI/CVD of the pyrocarbon matrix. No final heat treatment is needed to achieve the balance of hardness in the fiber and matrix. The composites of the present invention do not have pitch-based fibers or matrices nor do they have resin-based matrices.

Abstract: A gas preheater (10) that includes an exit plate (20) having first and second sides (22, 24) and a plurality of through holes (26) and at least one body (34) mounted adjacent the first side (22), the at least one body (34) having a first end (36) and a second end (38), the second end (38) located between the body first end (36) and the exit plate first side (22), at least one sidewall (40) connecting the first and second ends (36, 38), a body opening (42) in the first end (36) extending into the body (34) and defining a body inner wall (44), and a plurality of passages (46) extending between the at least one sidewall (40) and the body inner wall (44).

Abstract: Methods and apparatus to monitor a process of depositing a constituent of a multi-constituent gas are disclosed. The methods and apparatus may be used in a process for producing a carbon-carbon composite brake disc.

Abstract: A method and brake disc assembly to utilize worn refurbished brake material is disclosed. The method discloses the use of a brake disc for braking and the subsequent machining or refurbishment of the brake disc so that the brake disc can be used for three tours of braking to increase the utilization of the brake material.

Abstract: Method for densifying porous carbon preforms. The method including: providing an apparatus charged with at least one stack of annular porous carbon-carbon composite preforms, the preforms being separated from one another by spacers emanating from a passive heat distribution element centrally located within a cylindrical space formed by the stack of annular preforms; locating the charged apparatus in a furnace at a temperature of 950-1100° C. and a pressure of 5-40 torr; and circulating a carbon-containing gas reactant through the apparatus for 150 to 900 hours. Also, an apparatus for practicing this method. The preforms are densified with less physical damage due to the weight of the preforms being treated than are preforms made by otherwise identical processes that do not separate preforms from the preforms immediately above and below them by spacer elements comprising tabs or shelves emanating from a central passive heat distribution structural member.

Abstract: A template (10) configured for use with an annular preform (26) having a periphery (32) and an inner opening (34), the template (10) having an annular body with an outer periphery (16) and an inner opening (18) and a plurality of spacer openings (12) through its body each for receiving a spacer (25), one of the template inner opening (18) and the template outer periphery (16) having a width equal to the width of the preform inner opening (34) or the preform outer periphery (32). Also a method for densifying preforms that includes a step of positioning spacers using a template.

Abstract: A furnace spacer (10, 30, 50, 70) for spacing a first annular preform (22) from a second annular preform (22) in a furnace (100), each of the first and second annular preforms (22) having an outer periphery and a width and an inner opening having a periphery and a width, the spacer (10, 30, 50, 70) having an annular body (12, 32, 52, 72) having an inner diameter and an outer diameter. Also a method of alternately stacking spacers and preforms in a furnace.