Abstract: Method for producing carbon-carbon composite brake discs by: (a) providing annular nonwoven carbon fiber brake disc preforms; (b) carbonizing the brake disc preforms; (c) densifying the carbonized preforms by CVD/CVI (chemical vapor deposition/chemical vapor infiltration); (d) densifying the products of step (c) with isotropic or mesophase pitch by VPI (vacuum pitch infiltration) or RTM (resin transfer molding) processing; (e) carbonizing the preforms to remove non-carbon volatiles from the pitch and to open porosity in the pitch-infused preforms; (f) densifying the products of step (e) with isotropic or mesophase pitch by VPI or RTM processing; (g) carbonizing the preforms to remove non-carbon volatiles from pitch and to open porosity in the pitch-infused preforms; and (h) heat-treating the resulting pitch-densified carbon-carbon composite brake disc preforms. This manufacturing approach reduces lot-to-lot variability in friction performance of the resulting carbon-carbon composite brake discs.

Abstract: A method for the manufacture of carbon-carbon composite brake discs comprises (a) heat treating a carbon-carbon composite preform in the shape of a brake disc at 1600-2540° C., (b) directly following heat treating, subjecting the heat-treated preform to Chemical Vapor Deposition/Chemical Vapor Infiltration processing, (c) infiltrating the preform with an isotropic low to medium char-yield pitch derived from coal tar, employing Vacuum Pitch Infiltration processing or Resin Transfer Molding Processing, (d) stabilizing and carbonizing the pitch-infiltrated preform (e) machining the surfaces of the resulting carbonized preform, and (f) repeating steps (c) through (e) at least two additional times to raise the density of the carbon-carbon composite preform to at least approximately 1.75 g/cc.

Abstract: A method of manufacturing pitch-based carbon-carbon composite useful as a brake disc, includes (a) providing annular carbon fiber brake disc preform; (b) heat-treating the carbon fiber preform; (c) infiltrating the carbon fiber preform with pitch feedstock by VPI or RTM processing; (d) carbonizing the pitch-infiltrated carbon fiber preform; (e) repeating steps (c) and (d) to achieve a density in the carbon fiber preform of approximately 1.5 g/cc to below 1.7 g/cc; and (f) densifying the preform by CVI/CVD processing to a density higher than 1.7 g/cc. Employing lower cost VPI and/or RTM processing in early pitch densification cycles and using more expensive CVI/CVD processing only in the last densification cycle provides C-C composites in which the pitch-based components resist pullout, resulting in a longer wearing composite.

Abstract: Economically attractive method of making carbon-carbon composite brake disc or pad. The manufacturing method herein provides lowered manufacturing cycle time and reduced cost of manufacturing while enabling increased density of the final composite. The method includes: providing a fibrous nonwoven fabric segment produced from high basis weight fabric; optionally needling sequential layers of the fabric segments together to construct a brake disc or pad preform; carbonizing the fibrous preform to obtain a carbon-carbon preform; and infiltrating the resulting carbonized needled fibrous fabric preform via pitch or pitch and CVD/CVI processing in order to produce a carbon-carbon composite brake disc or pad which has a final density of 1.60 to 1.90 grams per cubic centimeter.

Abstract: Method for manufacturing pitch-densified carbon-carbon composite brake discs from carbon fiber preforms, by the following sequential steps: (a) providing a carbon-carbon composite brake disc preform; (b) heat treating the preform; (c) subjecting the heat-treated preform to Chemical Vapor Deposition/Chemical Vapor Infiltration processing; (d) infiltrating the preform with an isotropic low to medium char-yield pitch by Vacuum Pitch Infiltration processing or Resin Transfer Molding processing; (e) carbonizing the pitch-infiltrated preform; (f) machining the surfaces of the resulting carbonized preform; and (g) repeating steps (d) through (f) until the density of the carbon-carbon composite preform is at least 1.70 g/cc. The use of VPI equipment with isotropic, low to medium char-yield pitches for all densification steps following an initial CVD densification reduces capital and pitch materials cost.

Abstract: Method of manufacturing pitch-based carbon-carbon composite useful as a brake disc, by: (a) providing annular carbon fiber brake disc preform; (b) heat-treating the carbon fiber preform; (c) infiltrating the carbon fiber preform with pitch feedstock by VPI or RTM processing; (d) carbonizing the pitch-infiltrated carbon fiber preform; (e) repeating steps (c) and (d) to achieve a density in the carbon fiber preform of approximately 1.5 g/cc to below 1.7 g/cc; and (f) densifying the preform by CVI/CVD processing to a density higher than 1.7 g/cc. Employing lower cost VPI and/or RTM processing in early pitch densification cycles and using more expensive CVI/CVD processing only in the last densification cycle provides C-C composites in which the pitch-based components resist pullout, resulting in a longer wearing composite.

Abstract: Method of making a carbon-carbon composite brake disc or pad by: needling a plurality of layers of fibrous fabric segments to one another to form a brake disc or pad preform; carbonizing the fibrous preform to provide a carbon fiber brake disc or pad preform having a fiber volume fraction in the range 17% to 30% in the brake disc or pad preform; densifying the resulting carbonized needled fibrous fabric preform with pitch (isotropic or anisotropic) or with pitch and CVD/CVI; carbonizing the resulting pitch-infiltrated carbon fiber disk to carbonize the pitch therein; heat-treating the resulting pitch-densified carbon brake disc or pad; and subjecting the carbon brake disc or pad to a final cycle of CVD/CVI processing in order to produce a carbon-carbon composite brake disc or pad having a density of at least 1.70 g/cc and having a uniform through-thickness density.

Abstract: Low cost isotropic and/or mesophase pitch is used to densify carbon fiber preforms by VPI and/or RTM equipment in place of CVI/CVD processing, for reduced manufacturing cycle times and costs and reduced need for expensive densification equipment. The process includes: heat treating a carbon fiber preform; infiltrating the preform with a pitch feedstock by VPI and/or RTM; carbonizing the pitch-infiltrated carbon fiber preform at 1200-2450° C. with a hold time of 4 hrs to ensure the entire furnace reaches the max temperature; repetition of the pitch infiltration and carbonization steps until the density of the preform is about 1.7 g/cc or higher; and a final heat-treatment of the densified composite. Brake discs manufactured in this way have higher densities and better thermal characteristics, which result in improved mechanical properties and friction and wear performance as compared with conventional CVI/CVD-densified brake discs.

Abstract: Method of making carbon-carbon composite brake disc or pad. The manufacturing method herein benefits from lowered manufacturing cycle time, reduced cost of manufacturing, and at the same time increased density of the final composite. The method includes: providing a fibrous nonwoven fabric segment comprised of OPAN fibers, the segment being produced from high basis weight fabric; providing a needler to needle layers of the fabric segments to one another; needling two layers of the fabric segments to one another and then needling sequential layers of the fabric segments on top of the layers thereof which have previously been needled together, to construct a brake disc or pad preform; carbonizing the fibrous preform to obtain a carbon-carbon preform; and infiltrating the resulting carbonized needled fibrous fabric preform via CVD/CVI processing in order to produce a carbon-carbon composite brake disc or pad which has a density of at least 1.70 grams per cubic centimeter.

Abstract: Carbon-carbon composites made by needling together woven or nonwoven fabric made from carbon-containing fibers followed by carbonizing the fabric preforms. The carbon fiber preforms can be needled either in a carbonized or in an uncarbonized state. The un-carbonized fiber preforms would go through a carbonization/heat-treat step following the needling process. Final preform thickness and fiber volume is also controlled at carbonization, for instance by varying the level of pressure applied to the preforms during carbonization. Thus, the preforms may be unconstrained during carbonization (i.e., no pressure is applied to them). Or the preforms may be constrained during carbonization, typically by means of applying pressure (e.g., weight placed on top of the preforms). The preforms are then infiltrated via CVD/CVI processing in order to increase their density, resulting in a carbon-carbon composite which is suitable for use as, for instance, a brake disc or pad in aircraft and automotive brake systems.

Abstract: Carbon-carbon composite brake discs are manufactured by processes that include the use of PAN or pitch fibers and their combinations, combined with pitch, resin, or CVD/CVI matrix carbons. An additional process step is provided, in which a controlled amount of a carbon additive, such as carbon black and/or activated carbon, is infiltrated in to the bulk porosity of the composite prior to one or more of the densification cycles. Typical methods of infiltration include use of a solution or suspension of the powdered carbon in water or solvent solution so as to uniformly distribute the particulates throughout porosity within the carbon fiber preform prior to one or more of the densification cycles. The presence of the activated carbon and/or carbon black additive, distributed throughout the carbon-carbon composite brake disc, facilitates the adsorption and retention of available moisture in the composite.

Abstract: Method for making carbon-carbon composite friction product, by: fabricating carbon fiber preform; heat-treating the carbon fiber preform; infiltrating the carbon fiber preform with a high carbon-yielding pitch using VPI (vacuum pressure infiltration) or resin transfer molding (RTM) processing; carbonizing the preform with an intermediate heat-treatment at 800-2000° C.; repeating the pitch infiltration and carbonization steps to achieve a final density of >1.75 g/cc; machining the surfaces of the preform; and applying an oxidation protection system. This approach overcomes problems inherent in lower density carbon-carbon composites by employing high carbon-yielding pitches to densify the carbon-carbon composites to a high density. The high carbon yielding pitches may include isotropic pitches, 100% anisotropic (mesophase) pitches, or mixtures of the two. They may be derived from petroleum, coal tar, or synthetic feedstocks.

Abstract: Method of manufacturing pitch-based carbon-carbon composite useful as a brake disc, by: (a) providing annular carbon fiber brake disc preform; (b) heat-treating the carbon fiber preform; (c) infiltrating the carbon fiber preform with pitch feedstock by VPI or RTM processing; (d) carbonizing the pitch-infiltrated carbon fiber preform; (e) repeating steps (c) and (d) to achieve a density in the carbon fiber preform of approximately 1.5 g/cc to below 1.7 g/cc; and (f) densifying the preform by CVI/CVD processing to a density higher than 1.7 g/cc. Employing lower cost VPI and/or RTM processing in early pitch densification cycles and using more expensive CVI/CVD processing only in the last densification cycle provides C-C composites in which the pitch-based components resist pullout, resulting in a longer wearing composite.

Abstract: Low cost isotropic and/or mesophase pitch is used to densify carbon fiber preforms by VPI and/or RTM equipment in place of CVI/CVD processing, for reduced manufacturing cycle times and costs and reduced need for expensive densification equipment. The process includes: heat treating a carbon fiber preform; infiltrating the preform with a pitch feedstock by VPI and/or RTM; carbonizing the pitch-infiltrated carbon fiber preform at 1200-2450° C. with a hold time of 4 hrs to ensure the entire furnace reaches the max temperature; repetition of the pitch infiltration and carbonization steps until the density of the preform is about 1.7 g/cc or higher; and a final heat-treatment of the densified composite. Brake discs manufactured in this way have higher densities and better thermal characteristics, which result in improved mechanical properties and friction and wear performance as compared with conventional CVI/CVD-densified brake discs.

Abstract: Method for manufacturing pitch-densified carbon-carbon composite brake discs from carbon fiber preforms, by the following sequential steps: (a) providing a carbon-carbon composite brake disc preform; (b) heat treating the preform; (c) subjecting the heat-treated preform to Chemical Vapor Deposition/Chemical Vapor Infiltration processing; (d) infiltrating the preform with an isotropic low to medium char-yield pitch by Vacuum Pitch Infiltration processing or Resin Transfer Molding processing; (e) carbonizing the pitch-infiltrated preform; (f) machining the surfaces of the resulting carbonized preform; and (g) repeating steps (d) through (f) until the density of the carbon-carbon composite preform is at least 1.70 g/cc. The use of VPI equipment with isotropic, low to medium char-yield pitches for all densification steps following an initial CVD densification reduces capital and pitch materials cost.

Abstract: Method for producing carbon-carbon composite brake discs by: (a) providing annular nonwoven carbon fiber brake disc preforms; (b) carbonizing the brake disc preforms; (c) densifying the carbonized preforms by CVD/CVI (chemical vapor deposition/chemical vapor infiltration); (d) densifying the products of step (c) with isotropic or mesophase pitch by VPI (vacuum pitch infiltration) or RTM (resin transfer molding) processing; (e) carbonizing the preforms to remove non-carbon volatiles from the pitch and to open porosity in the pitch-infused preforms; (f) densifying the products of step (e) with isotropic or mesophase pitch by VPI or RTM processing; (g) carbonizing the preforms to remove non-carbon volatiles from pitch and to open porosity in the pitch-infused preforms; and (h) heat-treating the resulting pitch-densified carbon-carbon composite brake disc preforms. This manufacturing approach reduces lot-to-lot variability in friction performance of the resulting carbon-carbon composite brake discs.

Abstract: Methods and apparatuses for combining raw fibrous and binding materials in single mixing step (Step S3), followed by consolidation (Step S5) to greatly shorten overall cycle time to finished fiber-reinforced composite part. Chopped fibrous materials and binder materials are deposited sequentially onto belt conveyor (Step S2) so that materials are successively layered on top of one another in predetermined ratio and subsequently mixed (Step S3) to achieve uniform dispersion throughout. Mixed materials are deposited into rotating mold (Step S4), which further ensures uniform dispersion of fibrous and binder materials. Impregnation of fibrous materials with the binder material occurs in situ as uniformly mixed materials are heated and subsequently compacted in mold (Step S5) to obtain desired shape of fiber-reinforced composite part. Rotation device including: turntable for rotating mold; and actuator for supporting turntable and providing reciprocating motion to mold.

Abstract: Carbon-carbon composite material article and method of manufacturing it. The carbon-carbon composite material comprises a carbonized woven or nonwoven fabric-based preform which is subjected to rapid densification, e.g. using a resin transfer molding process, and which may subsequently be infiltrated with a ceramic additive solution in order to improve wear and friction properties. The method comprises densifying the preform and subsequently adding a ceramic additive to it to infiltrate the material with the additive and enhance the properties of the final product.

Abstract: A method and apparatus for combining raw fibrous and binding materials in a single mixing step (Step S3), followed by consolidation (Step S5) so as to greatly shorten the overall cycle time to a finished fiber-reinforced composite part. Chopped fibrous materials and binder materials are deposited sequentially onto a belt conveyor (Step S2) so that the materials are successively layered, one on top of each other in a predetermined ratio, and subsequently mixed (Step S3) to achieve uniform dispersion throughout. The mixed materials are then deposited into a rotating mold (Step S4) to further ensure uniform dispersion of fibrous and binder materials. Impregnation of the fibrous materials with the binder material occur in-situ as the uniformly mixed materials are heated and subsequently compacted in the mold (Step S5) to obtain the desired shape of the fiber-reinforced composite part.

Abstract: A method and apparatus for combining raw fibrous and binding materials in a single mixing step (Step S3), followed by consolidation (Step S5) so as to greatly shorten the overall cycle time to a finished fiber-reinforced composite part. Chopped fibrous materials and binder materials are deposited sequentially onto a belt conveyor (Step S2) so that the materials are successively layered, one on top of each other in a predetermined ratio, and subsequently mixed (Step S3) to achieve uniform dispersion throughout. The mixed materials are then deposited into a rotating mold (Step S4) to further ensure uniform dispersion of fibrous and binder materials. Impregnation of the fibrous materials with the binder material occur in-situ as the uniformly mixed materials are heated and subsequently compacted in the mold (Step S5) to obtain the desired shape of the fiber-reinforced composite part.