Abstract: A carbon-fiber-reinforced SiC composite having a high tensile strength is produced by impregnating a carbon-fiber-reinforced carbon composite with melted metal Si. The carbon-fiber-reinforced carbon composite includes carbon fibers that are pitch-based short carbon fibers. The pitch-based short carbon fibers are oriented in two-dimensional random directions. The carbon-fiber-reinforced carbon composite has a bulk density of 1.2 to 1.7 g/cm3, a porosity of 15 to 40 vol %, and a carbon fiber volume content of 20 to 50 vol %.

Abstract: A carbon-fiber-reinforced SiC composite having a high tensile strength is produced by impregnating a carbon-fiber-reinforced carbon composite with melted metal Si. The carbon-fiber-reinforced carbon composite includes carbon fibers that are pitch-based short carbon fibers. The pitch-based short carbon fibers are oriented in two-dimensional random directions. The carbon-fiber-reinforced carbon composite has a bulk density of 1.2 to 1.7 g/cm3, a porosity of 15 to 40 vol %, and a carbon fiber volume content of 20 to vol %.

Abstract: A sliding material consisting of a carbon-fiber reinforced carbon composite material containing fine particles of a simple substance of any of Group IV to Group VI elements or a carbide, a nitride or an oxide thereof.

Abstract: A sliding material consisting of a carbon-fiber reinforced carbon composite material containing fine particles of a simple substance of any of Group IV to Group VI elements or a carbide, a nitride or an oxide thereof.

Abstract: Pitch based carbon fiber wherein the spread La of graphite crystallites constituting a fiber in the direction of layer plane is 1000 angstroms or less; the orientation angle &PSgr; in the direction of fiber axis is 10° or less, and the following relationship formulas (1) and (2) are satisfied: 0.70La−46&PSgr;>50  (1) 0.55La−76&PSgr;<500  (2).

Abstract: Disclosed herein is a method for preparing carbon fiber reinforced carbon composites comprising:subjecting short fibers composed of bundles of multiple single fibers to dry or wet fibrillation;preparing a sheet oriented in the two-dimensional random direction; andafter impregnating the obtained sheet with resins pitches and laminating the sheet followed by molding, subjecting the molded product to baking and densification treatments.

Abstract: A process for producing a carbon fiber reinforced carbon composite material, comprising dispersing a short fibrous bundle of carbon fibers which comprises a plurality of single fibers, preparing a sheet in which fibers are in the two-dimensional random orientation, impregnating with a resin or pitch, laminating and molding, and then applying a baking and densifying treatment, a dispersion degree of the bundle of carbon fibers being controlled based on the formula (1) expressing correlation between the dispersion degree of the bundle of carbon fibers and the mechanical strength of the carbon fiber reinforced composite material:Dispersion degree=A-B.times.coefficient of friction (1)wherein A and B are constants determined experimentally, to produce a carbon fiber reinforced carbon composite material having desired mechanical characteristic.

Abstract: A disc brake for a vehicle comprising a disc and pads, the disc being rotatable integrally with wheels and the pads capable of being brought into friction engagement with the disc. The disc comprises a baked carbon fiber reinforced carbon composite comprising dispersed bundles of short carbon fibers impregnated with a reinforcing material of primarily a pitch. The pads comprise a baked carbon fiber reinforced carbon composite comprising dispersed bundles of short carbon fibers impregnated with a reinforcing material of primarily a pyrolytic carbon and a thermosetting resin.

Abstract: The present invention discloses a disc brake for a vehicle having a disc which is rotatable integrally with the wheels and pads which are brought into friction engagement with the disc. The disc is prepared by impregnating a reinforcing material into a carbon fiber reinforced carbon composite obtained by dispersing bundles of multiple single short carbon fibers with primarily a pitch, a combination of a pyrolytic carbon and a pitch or a combination of a pyrolytic carbon and a thermosetting resin, followed by baking; whereas the pads are prepared by impregnating a reinforcing material into a carbon fiber reinforced carbon composite obtained by dispersing bundles of multiple single short carbon fibers with primarily a combination of a pyrolytic carbon and a thermosetting resin or a combination of a pitch and a thermosetting resin, followed by baking.