摘要:
Small ceramic particles (e.g., of TiC) are incorporated into fibers. The ceramic particles enhance the friction and/or wear properties of a carbon-carbon composite article made with the impregnated or coated fibers. The impregnated fibers can be, e.g., polyacrylonitrile (PAN) fibers, pitch fibers, and other such fibers as are commonly employed in the manufacture of C-C friction materials. The impregnated fibers can be used to make woven, nonwoven, or random fiber preforms or in other known preform types. Preferred products are brake discs and other components of braking systems. The particles may be included in the fibers by mixing them with the resin employed to make the fibers and/or by applying them to the surfaces of the fibers in a binder.
摘要:
Process of manufacturing carbon-carbon composite preform by: (i.) arranging batch of carbon fiber preforms in infiltration vessel; (ii.) flooding vessel with hot liquid phase pitch at atmospheric pressure in inert atmosphere; (iii.) raising pressure in infiltration vessel to elevated pressure, and then slowly lowering pressure; and (iv.) repeating step (iii.). An apparatus that may be used is a heated infiltration vessel capable of operating at pressures above 100 psi, possible equipped with means to circulate heated pitch inside the vessel, in order to facilitate heat transfer into the carbon fiber preforms being infiltrated by the pitch. The need for a vacuum pump is eliminated, and the time spent heating the preform is substantially reduced. Instead of vacuum, cycled high pressure is employed to infiltrate carbon fiber preforms with pitch. The use of preheated pitch as a heat transfer agent avoids the slow transfer of heat into the preform prior to infiltration.
摘要:
A method of manufacturing a carbon-carbon brake disc uses a restraint fixture (12) 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).
摘要:
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.
摘要:
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.
摘要:
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. The layer of activated carbon or other friable material between the fibrous preform and the constraint fixture also provides an easily crushable region that facilitates removal of the preform from the constraint fixture after carbonization.
摘要:
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.
摘要:
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.
摘要:
A method of manufacturing a carbon-carbon brake disc uses a restraint fixture (12) 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).
摘要:
Method of joining carbon-carbon composite pieces together, e.g. in the refurbishment of aircraft brake discs. The method includes the steps of: providing a first carbon-carbon composite piece and a second carbon-carbon composite piece, wherein the second carbon-carbon composite piece has a surface that is complementary to a surface of said first carbon-carbon composite piece; providing a layer of a mixture of titanium powder and carbon powder on the first complementary mating surface; arranging the second carbon-carbon composite piece on the powder layer such that the second complementary mating surface is matched to the first complementary mating surface, thereby forming a construct of the first carbon-carbon composite piece, the powder layer, and the second carbon-carbon composite piece; placing the construct into a press and applying pressure to the construct to press together the two pieces joined at their complementary surfaces; and applying an electrical current to the powder in the construct to initiate an oxidation-reduction reaction, thereby bonding the carbon-carbon composite pieces together. The titanium powder particles may be from 25 to 250 microns in diameter, and the carbon powder (e.g., graphite particles) may be 1 to 10 microns in diameter.