Abstract: An apparatus for bonding a first carbon composite to a second carbon composite through a reactant layer includes a housing, and a pair of conductive press plates electrically isolated from the housing. The press plates are adapted to position the two parts to be bonded with a reactant layer therebetween. The press plates are subjected to an electrical potential and a clamping force, sufficient to initiate a combustion reaction that creates a molten ceramic to bond together the carbon-carbon composites.

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: An apparatus for bonding a first carbon composite to a second carbon composite through a reactant layer includes a housing, and a pair of conductive press plates electrically isolated from the housing. The press plates are adapted to position the two parts to be bonded with a reactant layer therebetween. The press plates are subjected to an electrical potential and a clamping force, sufficient to initiate a combustion reaction that creates a molten ceramic to bond together the carbon-carbon composites.

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 protecting carbon-carbon composite brake disc against migration of anti-oxidant composition through the porosity of the composite brake disc. The method starts with a porous carbon-carbon composite brake disc, and densifies it to a density of 1.70 grams per cubic centimeter or higher. The densified brake disc is then machine to the required dimensions. The pores in the densified brake disc are closed by subjecting it to CVD/CVI processing employing (i) a gaseous feedstock comprising natural gas spiked with 10 to 25% of a more reactive gas, and/or (ii) a temperature in the range of 1100° C. to 1500° C., and/or (iii) a gas pressure in the range 10 to 100 torr, and/or (iv) a gas flow rate of 300 cc/min to 450 cc/min. CVD/CVI processing carried out using these parameters deposits carbon within and closes the pores of the surface area of the carbon-carbon composite brake disc.

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: Method of joining carbon-carbon composite pieces together, e.g. in the refurbishment of aircraft brake discs.

Abstract: A metal powder is applied to the surface of the area of a carbon-carbon composite brake disc to be protected against migration of antioxidant. The metal powder may be titanium powder or tungsten powder. A chemical reaction between the metal powder and carbon is then initiated by heating the powder-coated brake to the ignition temperature via application of electric current (Joule preheating) or by heating it in a furnace. Upon combustion, the metal particles react with carbon in the composite, forming liquid carbide that flows into pores of the composite brake disc to be protected.

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: Method of manufacturing composite wheel beam key by: forming entirely from carbon fiber precursors or from carbon fiber precursors and ceramic materials a fibrous preform blank in a shape of a desired wheel beam key, wherein the fiber volume fraction of the preform blank is at least 50%; carbonizing the carbon fiber precursors; rigidifying the carbonized preform blank by subjecting it to at least one cycle of CVD; grinding the surface of the preform blank to open pores on its surface; and subjecting the open-pored preform blank to RTM processing with pitch. Also, carbon-carbon composite or carbon-ceramic composite wheel beam key produced by this process, having a density of from 1.5 g/cc to 2.1 g/cc and a maximum internal porosity of 10% or less.

Abstract: In the manufacture of carbon-carbon composite brake discs, migration of anti-oxidant substances into the friction surfaces is prevented by limiting or eliminating surface porosity in the carbon-carbon composite brake materials. The method includes infusing a suitable resin into pores in surface layers of the carbon-carbon composite disc and then charring the resin-infused disc to convert the resin in the pores to pyrolytic carbon. The resin may be infused into the carbon disc by submerging the disc in a molten resin. Prior to submerging the disc in the molten resin, the disc may subjected to a vacuum to remove air from the pores. While the disc is submerged in the molten resin, the pressure in the pressurizable vessel may increased to force the molten resin into the open porosity of the disc.

Abstract: Method of joining a carbon-carbon composite piece 30 together with a metal insert 20, e.g. in the manufacture of aircraft brake discs 10.

Abstract: Method for chemical bonding of fiberglass fibers to steel surfaces to prepare the steel for bonding with carbon composite material. This fiber-bonding step greatly increases the strength of the subsequent metal-composite bond. The fiberglass fibers which are chemically bonded to the steel provide a high surface area interface to entangle with carbon fibers in the composite component, and thereby inhibit crack formation on the boundary surface between the steel and composite components when they are bonded together.

Abstract: Method of manufacturing dense carbon-carbon composite material by: infiltrating a fibrous preform with pitch to form pitch-infiltrated preform; carbonizing the pitch-infiltrated preform; injecting resin or pitch into the preform in a mold; oxygen stabilizing the filled preform and carbonizing and heat-treating the oxygen-stabilized impregnated preform; and subjecting the preform to a single final cycle of chemical vapor deposition. This process reduces densification time as compared to comparable conventional carbon-carbon composite manufacturing procedures.

Abstract: A pitch densification process which is widely applicable in the densification of carbon fiber preforms and stabilized pitch fiber preforms. The process includes: (a.) introducing liquid pitch into a fibrous carbon preform; (b.) carbonizing the pitch-impregnated preform by heating it in the absence of oxidizing agents; and subsequently (c.) further densifying the carbonized pitch-impregnated preform. The pitch used for densification may be coal tar pitch, petroleum pitch, or synthetic pitch. The softening point of the pitch will normally range from 100° C. to 340° C., depending upon the properties to be imparted to the finished product.

Abstract: A brake disc rotor or stator is manufactured with slots in the interior face of the disc. A paste comprised of a fine powder of a carbide-forming metal along with fine carbon powder, suspended in an organic binder, is applied to the force-bearing areas in the rotor slot faces or the stator slot faces. The disc is then placed into a furnace in a nitrogen atmosphere and heated to the ignition temperature. When the furnace reaches the ignition temperature, a combustion reaction begins that creates a molten liquid ceramic material on the slot face. Upon cooling, the resulting brake disc has a tough, hard, abrasion-resistant ceramic surface on the portion of the brake disc slot that bears pressure.

Abstract: Method of manufacturing carbon-carbon composite brake disc comprising a dense reusable core. Preferably, the reusable core has a density of 1.8-2.05 g/cc. The method includes: forming a dense carbon-carbon composite core; positioning the dense core in a location within a carbon-carbon composite brake disc; and fixing the dense carbon-carbon composite core in place in its location within the carbon-carbon composite brake disc. It is economically advantageous to recover the dense core from a worn brake disc prior to positioning it in the brake disc. Also, an annular carbon-carbon composite brake disc made up of a friction surface containing 15-75 weight-% carbon-containing fibers and 25-85 weight-% resin binder and a dense carbon-carbon composite core comprising 40-75 weight-% carbon-containing fibers and 25-60 weight-% resin binder.