Abstract:
Mask (10, 10′, 21, 22, 30) for use in coating a carbon-carbon composite brake disc (25) with anti-oxidant. The mask is composed of carbon-carbon composite material or nonreactive ceramic material. The mask is configured with edge ridges (11, 13, 34, 36) that are aligned with the outer and inner annular diameters of the carbon-carbon composite brake disc, a gas flow channel (12, 32) between the ridges, and a gas access port (18, 40) that allows gas to enter the gas flow channel. The mask may also include a gas exit port (16) having a valve (17) operatively connected thereto, so that gas flow may be restricted when pressure within the mask and carbon-carbon composite brake disc falls below a specified minimum value. Also, a method of avoiding application of liquid antioxidant material to a friction surface of a carbon-carbon composite brake disc, by: covering the friction surface with a mask configured to deliver compressed gas to the friction surface, and directing compressed gas across the friction surface and through pores in the carbon-carbon composite brake disc and/or in the mask while the masked brake disc is in the presence of the antioxidant material in a liquid state.
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:
Mask (10, 10′, 21, 22) for use in coating a carbon-carbon composite brake disc (25) with anti-oxidant. The mask is composed of carbon-carbon composite material or nonreactive ceramic material. The mask is configured with edge ridges (11, 13) that are aligned with the outer and inner annular diameters of the carbon-carbon composite brake disc, a gasflow channel (12) between the ridges, and a gas access port (18) that allows gas to enter the gasflow channel. The mask may also include a gas exit port (16) having a valve (17) operatively connected thereto, so that gas flow may be restricted when pressure within the mask and carbon-carbon composite brake disc falls below a specified minimum value. Also, a method of avoiding application of liquid antioxidant material to a friction surface of a carbon-carbon composite brake disc, by: covering the friction surface with a mask configured to deliver compressed gas to the friction surface, and directing compressed gas across the friction surface and through pores in the carbon-carbon composite brake disc and/or in the mask while the masked brake disc is in the presence of the antioxidant material in a liquid state.
Abstract:
An adhesive applicator includes a base portion and an adhesive distributing portion. The base portion includes a first passageway extending from the exterior of the base portion to and through an integral cylindrical portion of the base portion. The adhesive distributing portion includes a plurality of passageways therethrough in communication with the first passageway of the base portion. The plurality of passageways of the adhesive distributing portion extend to the exterior of the adhesive distributing portion. An adhesive pump forces adhesive to and through the first passageway of the base portion and into and through the plurality of passageways of the adhesive distributing portion to the exterior of the adhesive distributing portion. Adhesive emanates from the exterior of the adhesive distributing portion under the force of the adhesive pump and coats the threads of an internally threaded device. Another example coats the threads of an externally threaded device. Processes for coating internal and external threads are disclosed.
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:
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:
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:
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).