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 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: 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: An apparatus and methods for transferring powder material from a storage drum to a processing container is disclosed. The apparatus has a dumper which receives a container of powder. The dumper moves the storage container between a loading position and an unloading position where the container is at least partially inverted.

Abstract: Constraint fixture for processing annular preforms. The constraint fixture is made up of a lower plate, a top plate, a ring for the outside diameter of an annular preform being treated within the constraint fixture, and a ring for the inside diameter of the annular preform. The outside diameter and inside diameter rings are made of thin flexible sheet metal strips or thin flexible carbon-carbon composite strip material. The thin flexible strips are joined together by deformable joints, so that the flexible constraint system retains pitch within the fibrous matrix of the preform. The outside diameter strips may be joined together by expandable joints and the inside diameter strips may be joined together by collapsible joints. Also, a method of avoiding damage to an annular fibrous preform, e.g., an aircraft brake disc preform, during a carbonization procedure. This method involves carbonizing the annular fibrous preform in the constraint fixture of the invention.

Abstract: Method of carbonizing pitch-infiltrated fibrous annular preform by: infiltrating the preform with pitch; placing the pitch-infiltrated preform in a constraint fixture having an ejector base plate, an inner wall, an outer wall, and a top press plate; selecting the relative sizes of the preform and the constraint fixture so that a layer of inert friable material may be situated between the preform and walls of the constraint fixture; placing inert friable material (e.g., activated carbon) between the preform and the top, bottom, and walls of the constraint fixture; and subjecting the pitch-infiltrated fibrous preform to carbonization in the constraint fixture. The activated carbon or other inert friable material adsorbs pitch molecules that escape the preform during carbonization, which reduces problems with foaming.

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: Process for producing carbon-carbon composite preform, by: providing short carbon fiber segments or short carbon fiber precursor segments; providing pitch in particulate form; combining blend comprising the fiber segments and pitch particles in a mold; subjecting the resulting mixture of fibers and pitch in the mold to an elevated pressure ranging at a temperature above the melting/softening point of the pitch to create an uncarbonized preform; cooling the preform to below its softening point and removing it from the mold; placing the preform in a constraint fixture; and carbonizing the combined components in the constraint fixture at an elevated temperature for a period of time of sufficient to provide a preform having a density in the range 0.8-1.6 grams per cubic centimeter.

Abstract: A resin transfer molding (RTM) apparatus (10) that includes: an extruder (4); at least two mold cavities (15) contained within a mold (16, 18) in the apparatus, arranged so that resin can be extruded from the extruder (4) into the mold; a nozzle (20) for delivering resin from the extruder (4) into the mold; runners (25) in the body of the mold to deliver resin from the nozzle (20) to a mold cavity (15) within the mold; a venting area (29) contiguous to each mold cavity to permit gases to escape from the mold cavity (15) when the mold cavity is infiltrated with resin; and a press (12) to force the mold (16, 18) closed during at least resin injection. An advantageous feature of the present invention is that the mold may be configured to accept a part (19) that is characterized by variations in length, width, and/or thickness, such as a wheel beam key. Also, an RTM process. The process includes: placing a porous preform, e.g.

Abstract: Method of making a carbon-carbon composite article such as an aircraft brake disc. The method includes: selecting carbon fiber precursors, having limited shrinkage in the axial direction when carbonized, in the form of individualized chopped or cut fibers; placing the selected chopped or cut carbon fiber precursors into a preform mold configured in the form of a brake disc to form a fibrous matrix; and then needling the molded fibrous matrix to provide it with three-dimensional structural integrity and to reduce layering. The carbon fiber precursor matrix may subsequently be infused with liquid carbon matrix precursor, the impregnated matrix may be carbonized; e.g., at 600-1800° C. for 1-10 hours to provide a preform having a density of at least about 1.1 g/cc, and the carbonized preform may be further densified to a density of at least about 1.6 g/cc by known liquid resin infiltration techniques and/or by conventional CVI/CVD processing.

Abstract: A mold fixture 20 for safe and efficient extraction, insertion and storage of mold inserts 26, 28 is provided. The mold fixture 20 includes a lower receiving area 24 for fixedly receiving a lower mold insert 28, an upper receiving area 22 for fixedly receiving an upper mold insert 26. The mold fixture 20 facilitates insertion or extraction of the upper and lower mold inserts 26, 28 into/from a molding machine 1 in a safe and secure manner. Furthermore, the upper and lower mold inserts 26, 28 can be securely stored within the mold fixture 20 at a storage location.

Abstract: Method for manufacturing a carbonized carbon-carbon composite preform, by: mixing (a) chopped carbon fiber, chopped stabilized pitch fiber, or chopped oxidized polyacrylonitrile (PAN) fiber, (b) thermoplastic pitch binder powder, and (c) activated carbon powder to form a mixture of 15-60 parts by weight of chopped carbon fiber or chopped stabilized pitch fiber or chopped oxidized PAN, 28-83 parts by weight of thermoplastic pitch binder powder, and 1-12 parts by weight of activated carbon powder; depositing this mixture into a mold; pressing/heating the materials in the mold to form a preform by compaction; removing the compacted preform from the mold; and carbonizing the compacted preform. The preform is preferably configured in the form of an aircraft landing system brake disc.

Abstract: A restraint fixture (12) is disclosed that includes a preform retention region configured to limit contracting forces applied against a preform (10) in the preform retention region when the restraint fixture (12) thermally contracts. In one embodiment, the restraint fixture (12) comprises a band (12) having a first surface defining the preform retention region and a first expansion portion (26, 28, 29) adapted to deform upon application of a force to the band (12).

Abstract: Molding apparatus for rapid transfer of molten resin or pitch in an infiltration molding process. The apparatus includes e.g. an extruder (4) for melting and conveying a resin or pitch and a mold (10) arranged so that resin or pitch is conveyed to a mold insert cavity (19) within the mold. The mold insert contains an internal protrusion such as a locating ring (25) for positioning a porous body (1, 18) within the mold insert cavity in a position that brings about unidirectional flow of the molten resin or pitch through the porous body. Also, rapid resin or pitch infiltration molding process that includes injecting a high melting point, high viscosity, molten resin or pitch into the mold to effect a unidirectional impregnation of a heated preform via a pressure gradient in the mold.

Abstract: A preform for a carbon-carbon composite part (55) comprising multiple layers of fibrous mats (51, 52, 53) wherein each of the fibrous mats (51, 52, 53) comprises a random carbon-containing fibrous matrix (11) within which is distributed a polymeric binder and wherein adjacent mat layers (51, 52, 53) are bound together by additional polymer binder, stitching and interlocking tabs. The preform of the present invention may be an aircraft landing system brake disc. Also, a method of manufacturing a thick multi-layer composite preform.

Abstract: Annular brake disc preform (15), wherein 40 to 80 layers of reinforcement fibers of at least two different lengths (11, 19) ranging from 10-60 mm are distributed in a planar gradient throughout the body of the preform, with the reinforcement fibers located near the exterior planes of the disc being predominately shorter fibers (11) and with the reinforcement fibers located in the central planes of the disc being predominately longer fibers (19).

Abstract: Methods of making a carbon-carbon composite preforms, particularly suitable as brake discs in aircraft landing systems, by combining titanium carbide particles ranging in size from 0.01 to 10 microns in diameter, resinous binder, and carbon fibers or carbon fiber precursors in a mold, and subsequently subjecting the combined components to pressure and heat to carbonize the resinous binder by methods, thereby providing the carbon-carbon composite preform having particulate titanium carbide uniformly distributed throughout its mass. Prior to combining the titanium carbide and the binder with the fibers in this process, the particulate titanium carbide may be mixed with liquid binder, the resulting TiC/binder mixture may then solidified, and the resulting solid TiC/binder mixture may be ground into a fine powder for use in the process. Also, compositions for preparing a carbon-carbon composite friction materials, and methods of improving wear and dynamic stability in a carbon-carbon composite brake discs.