Abstract: A friction or sliding body includes at least two composite materials reinforced with fiber bundles and containing a ceramics matrix. A first composite material forms the outside of the sliding body as a friction layer and a second composite material forms a supporting body joined areally to the friction layer. The fiber bundle lengths of the friction layer are significantly shorter than the fiber bundle lengths of the supporting body. The fiber bundles of the friction layer have a clear alignment perpendicular to the surface. The surface of the friction layer is formed substantially only of small regions of free carbon with a diameter of at most 1.2 mm, and a total fraction of the area of free carbon on the surface is at most 35%. The surface has an extremely fine crack structure and the friction layer exhibits virtually no stresses in the vicinity of the surface. A process for producing a friction or sliding body and a brake disc or brake lining are also provided.

Abstract: Activated porous carbon fibers, whose active centers are formed by pores that are filled at least in part by carbon and/or metal and/or metal carbide, obtainable by carbonization of organic or inorganic polymers, the use thereof for the adsorption or separation of gaseous substances, in particular of CO2, and also a method for the production thereof. The method includes the following steps. The first step is production of a spinning mixture containing polyacrylonitrile-based polymer A and an organic or metallo-organic polymer B. The next step is spinning of the spinning mixture to form mixed fibers of polymer A and polymer B. The next step is stabilization of the mixed fiber by oxidation. The next step is carbonization or graphitization of the mixed fiber under non-oxidizing conditions in such a way that the polymer B forms a carbon and/or metal and/or metal carbide residue of at least 25 wt %, this residue forming active centers.

Abstract: Process for producing hollow bodies comprising fiber-reinforced ceramic materials, where mold cores whose shape corresponds to that of the hollow spaces are produced in a first step, at least one mold core together with a press moulding composition or formable fiber composition are introduced into a mold, where the press moulding composition comprises carbon fibers and/or carbon filaments and thermally curable carbonizable binders, in such a way that the position of the cores corresponds to the desired position of the hollow spaces to be formed in a second step, the composition is cured in a third step by heating to a temperature of from 120° C. to 280° C., to give a green body, the strengthened green body is carbonized and or graphitized in a fourth step by heating in a nonoxidizing atmosphere to a temperature of from about 750° C. to about 2400° C.

Abstract: Protection products and armored products made of a fiber-reinforced composite material with a ceramic matrix, include a protection element for partial or complete absorption of at least one impact-like load focussed at a point. The protection element has a body having at least one dimension at least equal to 3 cm, in a direction perpendicular to a load to be absorbed. The body includes a fiber-reinforced composite material having a ceramic matrix with at least 10% by weight of silicon carbide and having reinforcing fibers. At least 5% by weight of the reinforcing fibers are carbon fibers and/or graphite fibers.

Abstract: Process for producing hollow bodies comprising fibre-reinforced ceramic materials, where cores whose shape corresponds to that of the hollow spaces are produced in a first step, a green body is produced in a second step by introducing the abovementioned cores and a press moulding compound into a mould, where the press moulding compound comprises carbon fibres and/or carbon threads and pitch and/or resins, the green body is cured in a third step by heating under pressure, the cured green body is carbonised in a fourth step by heating in the absence of oxidants to form a C/C body, and, if desired, the C/C body is infiltrated with liquid metal with retention of its shape in a fifth step, with at least partial formation of carbides occurring, where the cores comprise a material which in the fourth step melts without decomposition at a temperature above the curing temperature of the shaping by pressing of the press moulding compound; hollow bodies produced by this process and also their use as brake disks, clutch

Abstract: Friction members are composed of a ceramic composite material. The friction members can be used for motor vehicles as a clutch disk for friction clutches, for transmitting motive power, or as a brake disk. A friction zone of the friction member is composed of ceramic, in particular of Si and SiC. A core zone of the friction member is made from fiber-reinforced C/SiC, in particular of long fiber woven fabric-reinforced and short fiber-reinforced C/SiC.

Abstract: A brake system includes a friction coupling having organically or inorganically bound metal-containing, sintered-metal-containing and/or CFC-containing brake linings and a brake disc of fiber-reinforced C/SiC ceramic composite material. A friction layer and/or a surface of the brake disc subject to friction has a proportion of SiC greater than 65% and material compositions in a core region and a surface region of the brake disc are different. The brake system may be used in motor vehicles, rail vehicles or aircraft.

Abstract: Protection products and armored products made of a fiber-reinforced composite material with a ceramic matrix, include a protection element for partial or complete absorption of at least one impact-like load focussed at a point. The protection element has a body having at least one dimension at least equal to 3 cm, in a direction perpendicular to a load to be absorbed. The body includes a fiber-reinforced composite material having a ceramic matrix with at least 10% by weight of silicon carbide and having reinforcing fibers. At least 5% by weight of the reinforcing fibers are carbon fibers and/or graphite fibers.

Abstract: A method for the production of brake discs having friction areas made of ceramic materials, in particular composite materials, includes placing at least one ceramic portion in a diecasting mold and joining the ceramic portion with molten metals by casting under pressure into a rotationally symmetrical body which contains at least one ceramic (composite) segment that is disposed symmetrically relative to the axis of rotation of the metal body and juts out over at least one surface of the metal body perpendicular to the axis. A brake disc produced according to the method is also provided.

Abstract: A multilayer ceramic composite is described which contains at least one supporting zone having oxidation-sensitive reinforcing fibers as well as a matrix. The matrix optionally contains oxidation-sensitive components. The composite further contains at least one surface layer, as well as at least one additional protective layer disposed between the supporting zone and surface layer, and whose matrix is composed substantially of at least one component of the matrix of the supporting zone or cover layer. The protective layer further contains additives that form self-healing layers.

Abstract: A method is provided for producing a fiber-reinforced material which is composed, at least in a region of a surface layer, of a ceramic composite and has carbon-containing fibers reaction-bonded to a matrix containing the elements Si and C. In particular a method of producing fiber-reinforced silicon carbide is provided in which a structure of a matrix contains cracks and/or pores, at least at ambient temperature, because of a high thermal expansion coefficient compared with that of the fibers. Metals are selectively electrodeposited in the open pores and cracks of the matrix and, in particular, in a region of the electrically conductive reinforcing fibers. As a result, the open pores and cracks are filled and, in addition, metallic top layers are optionally formed that are firmly keyed to the ceramic composite and that may serve as an interlayer for glass top layers or ceramic top layers.

Abstract: A friction or sliding body includes at least two composite materials reinforced with fiber bundles and containing a ceramics matrix. A first composite material forms the outside of the sliding body as a friction layer and a second composite material forms a supporting body joined areally to the friction layer. The fiber bundle lengths of the friction layer are significantly shorter than the fiber bundle lengths of the supporting body. The fiber bundles of the friction layer have a clear alignment perpendicular to the surface. The surface of the friction layer is formed substantially only of small regions of free carbon with a diameter of at most 1.2 mm, and a total fraction of the area of free carbon on the surface is at most 35%. The surface has an extremely fine crack structure and the friction layer exhibits virtually no stresses in the vicinity of the surface. A process for producing a friction or sliding body and a brake disc or brake lining are also provided.

Abstract: A friction disc includes a cylindrical zone A, which is force-lockingly or frictionally connected to a shaft as a supporting disc, and at least one cylindrical annular zone B. The annular zone B has a side remote from the supporting disc in which recesses are formed. The recesses may be radially trapezoidal and/or involutely curved and/or elliptical and/or circular and/or polygonal and open and/or closed towards the periphery and/or the center. The material of the supporting disc A is a fiber-reinforced ceramic material shaped from a single piece in the green state prior to ceramization. The material of the annular zone B is a ceramic material which is optionally fiber-reinforced. The ceramic material of the annular zone B and the material of the matrix of the fiber-reinforced ceramic of the supporting disc A are selected independently of one another from silicon, silicon carbide, silicon nitride, carbon, boron nitride, boron carbide, Si/B/N/C and mixtures thereof.

Abstract: A friction disc, in particular a brake or clutch disc, includes carbon fiber-reinforced ceramic composite material with at least one top surface formed as a friction surface. At least part of the friction surface is formed of a different material, in particular of a carbon-containing material. The different material exhibits lower wear and oxidation resistance than that of the rest of the friction surface and a supporting zone of the friction disc. A visual, audible or mechanical signal is produced under operating conditions due to comparatively greater wear. The signal provides a warning that the service life of the friction disc is being exceeded. A process for producing the friction disc is also provided.

Abstract: A method for the production of brake discs having friction areas made of ceramic materials, in particular composite materials, includes placing at least one ceramic portion in a diecasting mold and joining the ceramic portion with molten metals by casting under pressure into a rotationally symmetrical body which contains at least one ceramic (composite) segment that is disposed symmetrically relative to the axis of rotation of the metal body and juts out over at least one surface of the metal body perpendicular to the axis. A brake disc produced according to the method is also provided.

Abstract: A method for operating an automatic cheese winder, having multiple winding stations (A, B, etc.) and a transportation system (21) for supplying the winding stations with spinning cops (39) and discharging them of empty tubes (40). The spinning cops are furnished by a preceding textile machine (30) having a spinning cop and empty tube transport device (31) communicating with the transportation system (21). The delivery of spinning cops to the winder (25) is continuously monitored by a sensor. A control device (46) of a tube monitor (24) assures that empty tube-equipped transport trays are kept on hand in the transportation system, and the tube monitor via the central control unit (27) initiates a controlled slow-down of the winder (25) into an energy-saving mode. Upon resumption of delivery of the spinning cops, the winder is accelerated from the energy-saving mode to an operating mode.

Abstract: A composite material article reinforced with high strength short graphite fibers and having a matrix substantially consisting of silicon carbide is prepared which has an elongation at break of 0.25 to 0.5% and thus exhibits quasi-ductile failure behavior. The short reinforcing graphite fibers are enclosed by at least two shells of graphitized carbon which have been obtained by impregnation with carbonizable impregnating agents and subsequent carbonization. The shell closest to the graphite fibers contains no cracks. The outermost shell is partially converted into silicon carbide. The starting material used comprises long or short fiber prepregs, which are first carbonized, then subjected at least once to an operation consisting of impregnation with a carbonizable impregnating agent and recarbonization, then graphitized at a temperature of up to a maximum of 2400° C. and then comminuted to yield a dry material for the production of a precursor article.

Abstract: A process for producing laminates which contain at least one centrally arranged, ion-conductive membrane which is, at least over a substantial part of its two mutually opposite flat faces, electrically conductively bonded to at least one catalytically active substance and to at least one two-dimensional, gas-permeable, electron-conductive contacting material, the bonding of at least two of the said components having been effected by lamination. The process comprises carrying out the bonding of the ion-conductive membrane, of the catalytically active substance and of the electron-conductive contacting material continuously. The ion-conductive membrane is brought together with at least the electron-conductive contacting material in the exact position by means of transport and feeding devices and the two components are laminated and bonded to one another by pressing them together. The range of variation in the a.c. resistances of the laminates produced by the process according to the invention is ±10%.

Abstract: A composite material article reinforced with high strength short graphite fibers and having a matrix substantially consisting of silicon carbide is prepared which has an elongation at break of 0.25 to 0.5% and thus exhibits quasi-ductile failure behavior. The short reinforcing graphite fibers are enclosed by at least two shells of graphitized carbon which have been obtained by impregnation with carbonizable impregnating agents and subsequent carbonization. The shell closest to the graphite fibers contains no cracks. The outermost shell is partially converted into silicon carbide. The starting material used comprises long or short fiber prepregs, which are first carbonized, then subjected at least once to an operation consisting of impregnation with a carbonizable impregnating agent and recarbonization, then graphitized at a temperature of up to maximum of 2400.degree. C. and then comminuted to yield a dry material for the production of a precursor article.

Abstract: A device for continuous thermal treatment of multidimensional sheet structures consisting of fibers (18) made of polyacrylonitrile or substantially polyacrylonitrile comprises a furnace (23) with chamber-like sections, through which sections the sheet structure is continuously moved on a gas permeable transport track (21). In each of the chamber-like sections there is a gas stream flowing through the sheet structure perpendicular to the sheet structure. In every section, devices measure the parameters of the gas stream temperature, pressure and gas flow above and below the sheet structure to control the operation of heating elements (26), fans (27) in the approach flow region, and fans (28) in the outflow regions of every section. These parameters are adjusted to predetermined values necessary for an effective and precise thermal treatment of the sheet structures (18).