Abstract: A composite material includes a ceramic matrix and two different fractions of fiber bundles, namely a reinforcing fiber bundle fraction and a matrix fiber bundle fraction having different average fiber bundle lengths. The fractions of fiber bundles are separated in a total fiber bundle distribution relative to a fiber bundle length by a minimum. A method for manufacturing a composite material and a method for manufacturing elements formed of a composite material are also provided.

Abstract: A method for producing expandable graphite intercalation compounds uses a thermal polyphosphoric acid which is added to an intercalation agent or to graphite. Preferably, the thermal polyphosphoric acid is used in a mixture with red, fuming nitric acid. Products produced from the graphite intercalation compounds through the expanded graphite stage, such as graphite foils, graphite laminates or graphite seals, have a comparatively high fluid tightness, are relatively resistant to oxidative attack, and can have comparatively high strengths. A further advantage is a good handling ability of the thermal polyphosphoric acids. A graphite foil is also provided.

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: 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: An electrodialytic method and device for the simultaneous production of acids and bases of high purity and higher concentration operates by splitting corresponding salts in aqueous solution using an electrolysis cell. The electrolysis cell includes a cathode chamber in which an alkali is formed, a salt chamber for supplying a salt to be split, an acid chamber in which the acid is formed, and an anode chamber through which a mineral acid flows as a proton carrier. The anode is a hydrogen-consuming electrode. The method and device are preferably used in the production of hydrochloric acid and sodium hydroxide solution.

Abstract: A packing yarn and a method of manufacturing a packing yarn composed of at least two bands which are at most 5 mm wide and are joined together by a yarn manufacturing method, include forming the bands of a laminate having at least one layer of flexible graphite and at least one layer of a metal foil with a tensile strength of at least 250 MPa. The layers of graphite foil and metal foil are joined by adhesion or through the use of a non-adhesive-like coupling agent. The bands are produced from the laminates by cutting, which is preferably effected continuously. Advantages thereof are that strips or bands of flexible graphite, which have a tensile strength that is totally inadequate for the manufacture of packing yarns, are altered in terms of their mechanical properties.

Abstract: A packing yarn and a method of manufacturing a packing yarn utilize at least two bands that are at most 5 mm wide and are joined together by a yarn manufacturing method. The bands are formed of a laminate having at least one layer of flexible graphite foil and at least one layer of a plastic foil with a tensile strength of at least 25 MPa and an elastic modulus of at least 0.4 GPa. The layers of graphite foil and plastic foil are joined by adhesive bonding, by a non-adhesive-like coupling agent or by welding. The bands are produced from the laminates by cutting, which is preferably effected continuously.

Abstract: A multilayer sheet having high compressive strength, high heat resistance and low permeability relative to fluids, includes layers of graphite foils and metal foils disposed alternating one upon another and parallel, with the graphite foils joined to the metal foils. Each of two layers forming an upper and a lower boundary of the multilayer sheet is a metal foil having a flat outwardly-directed surface completely covered with and joined to a gas-tight foil made of an organic polymer having a long-term temperature stability of at least 150° C. Preferably, no adhesives are used for joining the foils. The multilayer sheet is preferably used for producing flat gaskets.

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 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).

Abstract: Method for converting two-dimensional or three-dimensional sheet structures consisting of polyacrylonitrile fibres or substantially of polyacrylonitrile fibres, such as woven fabrics, layered materials, knitted fabrics, felts, or non-woven fabrics, into the thermally stabilized but non-carbonized state, by means of an oxygen-containing or oxygen-yielding gas flowing through the respective sheet fibre structure. This gas or gas mixture is used as a medium for the temperature control in the sheet fibre structure and as a means for supplying the oxygen carrier and also removing the gaseous reaction products. Temperature and flow velocity of the gas/gas mixture are matched to the stabilization characteristic of the respective sheet fibre structure and are controlled precisely. The device used for carrying out the method consists of a furnace (23) which consists of at least one chamber, through which furnace a web of the sheet fibre structure (18) is moved continuously.

Abstract: A method for the manufacture of shaped bodies by extrusion moulding of plastic-filler mixtures with filler contents of more than 50% by volume, preferably from 65 to 90% by volume, by means of an extruder with a conveying input zone. The method is restricted to use of fillers having good thermal conductivity. For carrying out the method, initially a mixture is manufactured from molten or fluid synthetic resin and the filler and this is ground and graded after cooling. Afterwards, there is extrusion of the ground mixture or of fractions separated from this and graded. According to a preferred variant of the method, an extruder is used for the extruding having a conveying input zone whose extrusion part consists merely of an input zone and an output zone.

Abstract: Process for manufacturing filler and distributing bodies essentially or carbon for process technology, in which ground cereal products are used as dry raw material and preferably water or aqueous synthetic resin preparations are used as binders. Dry material, preferably semolina, is mixed with the binder, the mixed composition is molded into primary product bodies and these are then hardened and subsequently coked or coked and graphitized. A typical use of the process involves the manufacture of small filler bodies of complicated shape.