Abstract: Method of chemical vapor infiltration of a deposable carbon material into a porous carbon fiber preform in order to densify the carbon fiber preform. The method includes the steps of: situating the porous carbon fiber preform in the reaction zone; providing a linear flow of a reactant gas comprising deposable carbon material in the reaction zone at an initial reaction pressure of at most 50 torr to produce deposition of the deposable carbon material into the preform; and adjusting the pressure of the gas to reaction pressures lower than said initial reaction pressure while deposable carbon material continues to be deposited into the porous carbon fiber preform. This method enables attainment of a target increased density in a carbon fiber preform much more quickly than known processes. A programmed pressure swing throughout the CVI/CVD run may be set in order to provide a linear increase in density.

Abstract: A method and brake disc assembly to utilize worn refurbished brake material is disclosed. The method discloses the use of a brake disc for braking and the subsequent machining or refurbishment of the brake disc so that the brake disc can be used for three tours of braking to increase the utilization of the brake material.

Abstract: Apparatus including a carbon-carbon composite pressure plate (32, 42) having a friction surface (33, 43) on one side thereof, a non-friction surface (37, 47) on the opposite side thereof, and a body (39, 49) between said surfaces. A wear pin housing (36, 46) containing a wear pin retainer (35, 45) is located in the pressure plate body (39, 49), the wear pin housing opening to the non-friction surface (37, 47) but not opening to the friction surface (33, 43). A wear pin (31), preferably made of carbon-carbon composite material, is located in the wear pin retainer (35, 45). The wear pin retainer (35, 45), which may be made of carbon-carbon composite material, is held in place in the wear pin housing (36, 46) by the interaction of threading in the wear pin housing (36, 36) and threading in the wear pin retainer (35, 45) and optionally also by a carbonizable resin adhesive located between the wear pin housing threading and the wear pin retainer threading.

Abstract: Process including steps (a.) through (c.). Step (a.) involves providing a mixture of 41-47 parts by weight phenol component and 54-58 parts by weight formaldehyde. The phenol component in this step is approximately ? by weight para-phenylphenol and ? by weight phenol. Step (b.) involves adding 2-12 parts by weight previously manufactured phenolic resole resin to the mixture formed in step (a.). Step (c.) involves allowing the resulting mixture of phenol, formaldehyde, and phenolic resole resin to react, thereby producing a phenolic resin having a high molecular weight fraction of at least 10 weight-percent. Also, phenolic resole resin made by the process of described herein. Such phenolic resole resin has an average molecular weight that is at least 10% lower and a viscosity that is at least 10% lower than a comparable phenolic resole resin made by carrying out steps (a.) and (c.) in the absence of step (b.) as described herein.

Abstract: This invention provides a stepped heating cycle for the pre-treatment of phenolic microballoons prior to carbonization thereof, wherein the heating cycle comprises the steps of sequentially: gradually elevating the temperature of the microballoons to a temperature in the range 100° C.-170° C.; holding the microballoons at the elevated temperature for 1-24 hours; and gradually cooling the microballoons. This invention also provides a heat-dissipation reactor (11, 21, 31) which comprises a walled reaction chamber having a bottom and no top, the reaction chamber being fitted with high thermal conductivity inserts. When used in accordance with this invention (61), the volume within the walls of the reaction chamber is charged with phenolic resin microballoons. In a preferred embodiment, the reaction chamber (11, 21) is subdivided into a plurality of subchambers by a vertical grid of aluminum plates (19, 29).

Abstract: This invention provides a stepped heating cycle for the pre-treatment of phenolic microballoons prior to carbonization thereof, wherein the heating cycle comprises the steps of sequentially: gradually elevating the temperature of the microballoons to a temperature in the range 100° C.-170° C.; holding the microballoons at the elevated temperature for 1-24 hours; and gradually cooling the microballoons. This invention also provides a heat-dissipation reactor (11, 21, 31) which comprises a walled reaction chamber having a bottom and no top, the reaction chamber being fitted with high thermal conductivity inserts. When used in accordance with this invention (61), the volume within the walls of the reaction chamber is charged with phenolic resin microballoons. In a preferred embodiment, the reaction chamber (11, 21) is subdivided into a plurality of subchambers by a vertical grid of aluminum plates (19, 29).

Abstract: An improved aircraft brake system and method of manufacturing the same. The system comprises a rotatable wheel axle, a heat treated stationary carbon disc secured to the wheel axle and a rotating carbon disc heat treated to a temperature substantially higher than the heat treating temperature of the stationary carbon disc and rotatably supported relative to the wheel axle and arranged parallel to the stationary carbon disc. The method comprises heat treating the rotating and stationary carbon discs to different final temperatures prior to assembly of the aircraft brake system.

Abstract: Brake disc with carbon composite body, wherein the surface of the brake disc is at least partially covered by a layer of an antioxidant composition that can be visualized by viewing it under “blacklight”. The brake disc of may be processed, before being incorporated into a brake system, to remove antioxidant composition that covers the working surface of the disc. An antioxidant coating composition may include from 10-75 wt % H2O, 20-65 wt % H3PO4, 0.1-20 wt % alkali metal mono-, di-, or tri-basic phosphate, 0-2 wt % hydrated boron oxide, 0-18 wt % KH2PO4, 3-10 wt % of a transition metal oxide, and 1-20 wt % zinc sulfide.

Abstract: Coated article, e.g., a brake disc, comprising a carbon-carbon composite component or a carbon-carbon-silicon carbide component coated at least with a phosphorus-containing antioxidant undercoating, the undercoating being covered by a silicon carbide particle-containing overcoating of alkali or alkaline earth metal silicate, pH modifier, and silicon carbide particles. Also, method of protecting a carbon-carbon composite brake disc or a carbon-carbon-silicon carbide composite brake disc against oxidation, by: coating the composite brake disc with a first phosphoric acid-based penetrant system; curing the penetrant coating at a temperature of 200° C. or above to form a first coating on the composite brake disc; applying the ceramic coating composition of claim 1 over the first coating and curing the ceramic coating at a temperature below 200° C.

Abstract: Method of chemical vapor infiltration of a deposable carbon material into a porous carbon fiber preform in order to densify the carbon fiber preform. The method includes the steps of: situating the porous carbon fiber preform in the reaction zone; providing a linear flow of a reactant gas comprising deposable carbon material in the reaction zone at an initial reaction pressure of at most 50 torr to produce deposition of the deposable carbon material into the preform; and adjusting the pressure of the gas to reaction pressures lower than said initial reaction pressure while deposable carbon material continues to be deposited into the porous carbon fiber preform. This method enables attainment of a target increased density in a carbon fiber preform much more quickly than known processes. A programmed pressure swing throughout the CVI/CVD run may be set in order to provide a linear increase in density.

Abstract: Process including steps (a.) through (c.). Step (a.) involves providing a mixture of 41-47 parts by weight phenol component and 54-58 parts by weight formaldehyde. The phenol component in this step is approximately ? by weight para-phenylphenol and ? by weight phenol. Step (b.) involves adding 2-12 parts by weight previously manufactured phenolic resole resin to the mixture formed in step (a.). Step (c.) involves allowing the resulting mixture of phenol, formaldehyde, and phenolic resole resin to react, thereby producing a phenolic resin having a high molecular weight fraction of at least 10 weight-percent. Also, phenolic resole resin made by the process of described herein. Such phenolic resole resin has an average molecular weight that is at least 10% lower and a viscosity that is at least 10% lower than a comparable phenolic resole resin made by carrying out steps (a.) and (c.) in the absence of step (b.) as described herein.

Abstract: The present invention relates to annular drive inserts which are placed within an annular opening within the brake disk. Preferably the annular drive inserts comprise carbon-carbon composite which has been treated with antioxidant. In a highly preferred embodiment the treatment is accomplished by vacuum impregnation. The antioxidant generally comprises a standard phosphoric acid based solution. This invention solves a need in the art for annular drive inserts that have improved resistance to oxidation and strength.

Abstract: Method for removing tar-forming hydrocarbons from an effluent gas mixtures from Chemical Vapor Deposition or Chemical Vapor Infiltration processes. Method includes passing at elevated temperature effluent gas mixture containing hydrogen, methane, and high molecular weight hydrocarbons through a bed that contains iron pellets, thereby decomposing tar-forming high molecular weight hydrocarbons in the effluent gas mixture. Apparatus including a de-tarring vessel (5) having a packed bed (7, 8, 9) of iron or iron oxide pellets (1) resting over a perforated distributor plate (2) and having an exhaust port (12), said de-tarring vessel being operatively linked via an exhaust port (6) to a CVI or CVD reactor vessel.

Abstract: Coated article, e.g., a brake disc, comprising a carbon-carbon composite component or a carbon-carbon-silicon carbide component coated at least with a phosphorus-containing antioxidant undercoating, the undercoating being covered by a silicon carbide particle-containing overcoating of alkali or alkaline earth metal silicate, pH modifier, and silicon carbide particles. Also, method of protecting a carbon-carbon composite brake disc or a carbon-carbon-silicon carbide composite brake disc against oxidation, by: coating the composite brake disc with a first phosphoric acid-based penetrant system; curing the penetrant coating at a temperature of 200° C. or above to form a first coating on the composite brake disc; applying the ceramic coating composition of claim 1 over the first coating and curing the ceramic coating at a temperature below 200° C.

Abstract: Method of improving humidity resistance in a coated article (19) comprising a carbon-carbon composite component (10), a graphite component (10), or a ceramic matrix composite component based on carbon fibers and/or graphite (10). The component (10) is preferably configured as an aircraft landing system brake disc. The method includes the steps of: (A) providing a carbon-carbon composite component (10), a graphite component (10), or a ceramic matrix composite component based on carbon fibers and/or graphite (10); (B) covering the component (10) with a phosphorus-containing antioxidant undercoating (11) having a thickness of approximately 1–10 mil; and (C) covering the resulting undercoated component (10, 11) with a boron-containing glass overcoating (12) having a thickness of approximately 1–10 mil. The overcoating includes 20–50 wt-% alkali or alkaline earth metal silicates, 3–25 wt-% alkali metal hydroxide, up to 10 wt-% boron nitride, and one or both of 5–40 wt-% elemental boron and 5–40 wt-% boron carbide.

Abstract: Coated articles (19) that comprise components, made of carbon fiber or carbon-carbon composites which may be configured, for example, as aircraft landing system brake discs. The components (10) are coated with a system that includes a phosphorus-containing undercoating (11) having a specified formulation and a boron-containing overcoating (12) having specified characteristics. The coated articles of the invention, e.g., aircraft brake discs, are protected against catalytic oxidation when the article is subjected to temperatures of 800° C. (1472° F.) or greater. Also, a method of protecting a component made of a carbon fiber or carbon-carbon composite simultaneously against catalytic oxidation (e.g., catalyzed by de-icer compositions) and high temperature non-catalytic oxidation.

Abstract: This invention provides a stepped heating cycle for the pre-treatment of phenolic microballoons prior to carbonization thereof, wherein the heating cycle comprises the steps of sequentially: gradually elevating the temperature of the microballoons to a temperature in the range 100° C.–170° C.; holding the microballoons at the elevated temperature for 1–24 hours; and gradually cooling the microballoons. This invention also provides a heat-dissipation reactor (11, 21, 31) which comprises a walled reaction chamber having a bottom and no top, the reaction chamber being fitted with high thermal conductivity inserts. When used in accordance with this invention (61), the volume within the walls of the reaction chamber is charged with phenolic resin microballoons. In a preferred embodiment, the reaction chamber (11, 21) is subdivided into a plurality of subchambers by a vertical grid of aluminum plates (19, 29).

Abstract: Carbon composite components (1, 11, 22, 30), which may be aircraft brake discs, heat exchanger cores, and so on, are covered by protective coating 32. Component (1, 11, 22, 30) is immersed in liquid bath precursor of fluidized glass (step 55). After immersion step, glass-coated component (1, 11, 22, 30) is removed and annealed. Heat treatment gradually increases temperature to 250-350° C. at the rate of 1-2° C. per minute (step 60). Heat treatment is followed by soak at temperature of 250-350° C. for 1-10 hours (step 65). Temperature is then increased to 550-650° C. (step 70). Temperature is maintained at 550-650° C. for 1-10 hours (step 75). After completion of second prolonged heat treatment, the component is cooled until reaching room temperature (step 80). Upon completion of the annealing step, the fluidized glass coating converts to solid glass coating (32) enveloping and forming a protective barrier against undesirable oxidation of the C—C component (1, 11, 22, 30).

Abstract: Antioxidant coating compositions containing 10-75 wt % H2O, 20-65 wt % H3PO4, 0.1-20 wt % alkali metal mono-, di-, or tri-basic phosphate, 0-2 wt % hydrated boron oxide, 0-18 wt % KH2PO4, 3-10 wt % of a transition metal oxide, and 0-20 wt % hydrated manganese phosphate, 0-25 wt % Al(H2PO4)3, and 0-10 wt % Zn3(PO4)2, provided that at least one of Al(H2PO4)3, Zn3(PO4)2, and hydrated manganese phosphate is present. Also, brake discs made from carbon composite articles having their surface treated with certain antioxidant coatings. During a manufacturing process, carbon matrix 15 of brake disc 11 is covered on its outer and inner edges with antioxidant layers 19 and portions of the working surface of brake disc 11 may also be covered with antioxidant layers 13, potentially decreasing the fitness of the brake disc for service. In accordance with this invention, brake disc 12 is manufactured from brake disc 11 by the removal from its working surface of antioxidant layers 13.

Abstract: Coated articles (19) that comprise components, made of carbon fiber or carbon-carbon composites which may be configured, for example, as aircraft landing system brake discs. The components (10) are coated with a system that includes a phosphorus-containing undercoating (11) having a specified formulation and a boron-containing overcoating (12) having specified formulation. The coated articles of the invention, e.g., aircraft brake discs, are protected against catalytic oxidation when the article is subjected to temperatures of 800° C. (1472° F.) or greater. Also, a method of protecting a component made of a carbon fiber or carbon-carbon composite simultaneously against catalytic oxidation (e.g., catalyzed by de-icer compositions) and high temperature non-catalytic oxidation.