Abstract: A method of producing a rigid catalytically active porous ceramic is disclosed. Catalyst particles comprising a catalytically active material or a precursor thereof are mixed with a chemical additive, a ceramic binder, a carrier liquid and, optionally, substantially inert carrier particles to obtain a slurry having a gel-or paste-like consistency. The slurry may be transported to a substrate, e.g., by printing, or to a reactor cavity by a suitable flow method. The slurry is then heated to substantially evaporate said carrier liquid to obtain a rigid, catalytically active porous ceramic in situ. A catalyst obtainable by such a method and the use of such a catalyst are also disclosed.

Abstract: A holding device that can be braced in a surveying machining together with an individual preparation model produced by dental laboratory techniques. The holding device has a mechanically stable frame with bores disposed at a distance (a) to one another, in which at least two holding pins are locked that can be displaced at least in the axial direction (A).

Abstract: A holding device that can be braced in a surveying machining together with an individual preparation model produced by dental laboratory techniques. The holding device has a mechanically stable frame with bores disposed at a distance (a) to one another, in which at least two holding pins are locked that can be displaced at least in the axial direction (A).

Abstract: A holding device that can be braced in a surveying machining together with an individual preparation model produced by dental laboratory techniques. The holding device has a mechanically stable frame with bores disposed at a distance (a) to one another, in which at least two holding pins are locked that can be displaced at least in the axial direction (A).

Abstract: A holding device that can be braced in a surveying machining together with an individual preparation model produced by dental laboratory techniques. The holding device has a mechanically stable frame with bores disposed at a distance (a) to one another, in which at least two holding pins are locked that can be displaced at least in the axial direction (A).

Abstract: A holding device comprises a cylindrical or prismatic, porous ceramic blank and elements for clamping in a machine tool for processing the blank by removing material, in order to produce a ceramic workpiece. A narrow frame is fixed by an adhesive connection over at least part of the periphery of the blank, which is held without stresses, in the area of a plane encompassing the longitudinal middle axis (A) of the blank. The frame only covers a small part of the surface of the blank and can be detached and held in a stable holder with a clamping adapter, in such a way that it cannot slide. The entire combination is fixed in the machine tool in such a way as to be resistant to twisting and sliding. The ceramic workpiece emerges continuously form the ceramic blank without predetermination of the advance direction, until holding segments which can then only be freely selected according to number and location have been formed.

Abstract: The invention relates to an automatic machine tool, for the production of base structures, for false teeth, in particular, for tooth crowns and/or tooth bridges of exact three-dimensional shape. Said base structures may be fixed to prepared natural and/or artificial tooth stumps. The machine tool comprises a machine frame, or a body, a work piece carrier, with a rotation shaft, at least one digitization unit, at least one machining unit and an electronic arithmetic and control unit for all drive lines. A carrier for the workpiece, a blank, and/or for the machining unit(s), serves as displacement unit, with three translational axes in the x-, y- and z-directions. The digitization of the preparation model and the machining of the blank are carried out on the same machine tool, at different times. The machining paths for the blank are calculated from the measured and stored digitized data and a predetermined material-specific scaling factor, before the machining of the blank.

Abstract: A holding device that can be braced in a surveying machining together with an individual preparation model produced by dental laboratory techniques. The holding device has a mechanically stable frame with bores disposed at a distance (a) to one another, in which at least two holding pins are locked that can be displaced at least in the axial direction (A).

Abstract: A holding device (42) comprises a cylindrical or prismatic, porous ceramic blank (10) and means for clamping in a machine tool for processing the blank (10) by removing material, in order to produce a ceramic workpiece (18). A narrow frame (12) is fixed by an adhesive connection over at least part of the periphery of the blank (10), which is held without stresses, in the area of a plane encompassing the longitudinal middle axis (A) of the blank. Said frame (12) only covers a small part of the surface of the blank (10) and can be detached and held in a stable holder (24) with a clamping adapter (34), in such a way that it cannot slide. The entire combination is fixed in the machine tool in such a way as to be resistant to twisting and sliding. The ceramic workpiece (18) emerges continuously from the ceramic blank (10) without predetermination of the advance direction, until holding segments (20) which can then only be freely selected according to number and location have been formed.

Abstract: The invention relates to a process for production of a sintered oxide ceramic of composition CexMyDzO2-a with dense structure without open porosity or with a predetermined porosity. The first doping element M is at least one element of the group consisting of the rare earths but M≠Ce, alkali and earth alkali metals. The educts are used with a second doping element D of at least one metal of the group consisting of Cu, Co, Fe, Ni and Mn, in the submicron particle size or as a salt solution, and sintered at a temperature in the range of 750-1250° C. into an oxide ceramic with extremely fine structure of a grain size of maximum around 0.5 &mgr;m.

Abstract: The invention relates to a process for production of a sintered oxide ceramic of composition CexMyDzO2-a with dense structure without open porosity or with a predetermined porosity. The first doping element M is at least one element of the group consisting of the rare earths but M≢Ce, alkali and earth alkali metals. The educts are used with a second doping element D of at least one metal of the group consisting of Cu, Co, Fe, Ni and Mn, in the submicron particle size or as a salt solution, and sintered at a temperature in the range of 750-1250° C. into an oxide ceramic with extremely fine structure of a grain size of maximum around 0.5 &mgr;m.

Abstract: In the case of filters for cleaning the exhaust gases of diesel engines, the deposited soot particles are burnt at intervals at temperatures between 550.degree. to 700.degree. C. By using filters consisting of open-pore ceramic foam manufactured by coating an open-pore body which can be burnt out, with a ceramic powder suspension, burning out the substrate material at temperatures of 100.degree.-500.degree. C. and then sintering at elevated temperatures, which filters comprise a self-supporting ceramic structure with an internal surface area of the total pore system of 1 m.sup.2 /l to 10 m.sup.2 /l and an open porosity of 55-92%, the soot combustion temperature is reduced to between 400.degree. to 550.degree. C. When coated with catalytically active substances, the soot combustion temperature is even reduced to 350.degree. C.

Abstract: In filters for cleaning the exhaust gases from diesel engines having openpored foam ceramic bodies, the deposited soot particles are burned up at temperatures of between 550.degree. and 700.degree. C. at periodic intervals. In order to lower the inflammation temperature of the soot in the regeneration phase of the filter, the ceramic bodies are catalytically coated.The region of the openpored foam ceramic body first subjected to the flow of the exhaust gases of the diesel engines has at least partly a denser pore structure than the remaining foam body so that the inflammation temperature can be lowered since temperature peaks occur in these regions on account of increased soot deposits, which temperature peaks lead to inflammation of the soot located there and consequently burn up all the soot deposited in the filter.

Abstract: A composite material comprising an open pore rigid foam of ceramic, metal, carbon or a plastics material and a solid filler material disposed in the cavities of the foam. The solid filler material forms areas on the surface of the composite material defined by the walls of the cavities in the foam. Depending on the material of the foam, the material filling its cavities may be a metal or a plastics material. The composite material, the production of which is also described, has aesthetic qualities which render it particularly suitable for the production of decorative articles.

Abstract: Filter medium in the form of a stable porous body of granules of spherical form bonded together by a different phase or by sintering. Preferably hollow spherical granules of corundum are manufactured into filter media in plate form. The filter media are employed for filtration of molten metal preferably aluminum.

Abstract: Ceramic, porous filter body in the designed to overcome the lack of high temperature resistant thermoshock resistant and mechanical stable bodies for the filtration of metals, preferentially of iron and ferrous alloys. This filter body has a temperature resistance of 1600.degree. C., a linear thermal coefficient of expansion of 3-7.times.10.sup.-6 /.degree.C. and consists of hollow spheres based on minimum one homogeneous distributed refractory material and another refractory material, which at high temperature by chemical reaction forms with the hollow spheres a solid refractory binding phase. A process for the production of such a filter body is described such, that the spheres of the refractory materials are mixed with a powderous binding phase, then formed to a porous body and then, by retention of the porous homogeneous structure under formation of new refractory compositions by heat treatment are chemically reacted, at least in the contact areas of the spheres.

Abstract: An exchangeable separator is horizontally located within a three-layer refining cell for the electrolytic purification of aluminum. This separator is freely movable in the vertical direction within a movement space (h) defined by a refractory frame. The porosity of the separator is at least 30%, preferably at least 50%, so that the electrolyte and metal can pass through the separator without any significant additional loss of potential.In industrial refining cells, the separator appropriately has a thickness of 0.5 to 2 cm and a disc-shaped design, the vertical movement space (h) being 0.5 to 1 cm. The level changes produced during the operation of the cell can be compensated for in this free movement space.