摘要:
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.
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:
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.
摘要:
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.
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:
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.
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.