Abstract: Transparent spinel ceramics, as they can be used, for example, as protective ceramics, and to a method for the production thereof. Transparent spinel ceramics which preferably contain no visible defects and which have an in-line transmission of more than 82% in wavelength ranges of infrared light, measured between 1000 nm and 2500 nm, at sample thicknesses?3 mm. Spinel ceramics transparent in wavelength ranges of infrared light which are composed of sintered magnesium aluminum spinel having an average structural grain size of ?10 ?m and having maximally 0.5 mass % overall of homogeneously distributed additives of calcium and/or strontium and/or barium which are present in a concentration, expressed respectively as an oxide, of 0.005 to <0.2 mass % CaO and/or 0.005 to <0.5 mass % SrO and/or 0.005 to <0.5 mass % BaO.

Abstract: Transparent spinel ceramics, as they can be used, for example, as protective ceramics, and to a method for the production thereof. Transparent spinel ceramics which preferably contain no visible defects and which have an in-line transmission of more than 82% in wavelength ranges of infrared light, measured between 1000 nm and 2500 nm, at sample thicknesses ?3 mm. Spinel ceramics transparent in wavelength ranges of infrared light which are composed of sintered magnesium aluminum spinel having an average structural grain size of ?10 ?m and having maximally 0.5 mass % overall of homogeneously distributed additives of calcium and/or strontium and/or barium which are present in a concentration, expressed respectively as an oxide, of 0.005 to <0.2 mass % CaO and/or 0.005 to <0.5 mass % SrO and/or 0.005 to <0.5 mass % BaO.

Abstract: Transparent composite pane for safety applications. The composite pane is composed of multiple layers which are arranged behind one another. At least one of the layers is composed of, a plate or plates arranged in a mosaic or in series, of monocrystalline magnesium aluminate spinel.

Abstract: The invention relates to the field of ceramics and relates to transparent composite panes for safety applications which are typically constructed from multiple layers of ceramic, glass and plastic plates possibly connected to one another by a connection medium and which have an increased loadability. The object of the invention is the disclosure of a transparent composite pane for safety applications which avoids both the previous transmission disadvantages and quality disadvantages of transparent polycrystalline ceramics and also the disadvantages in the protective effect, as Al2O3 monocrystals show them in comparison with fine-crystalline transparent Al2O3 sintered ceramics or spinel sintered ceramics. The object is attained by a transparent composite pane for safety applications, wherein the composite is composed of multiple layers which are arranged behind one another and at least one layer is a plate, or plates arranged in a mosaic or in series, of magnesium aluminate spinel.

Abstract: The present invention relates to highly dense translucent and transparent aluminium oxide components for applications, e.g. in the lighting industry, where a fine crystal size has to be obtained and stabilized for use at temperatures of 800° C. or more. Disclosed are high-strength polycrystalline alumina products which include 0.001-0.5 weight-% ZrO2 stabilizing a fine crystal size <2 ?m or, preferably, <1 ?m if used at temperatures of 800° C. or more. The microstructure exhibits an extremely high relative density enabling a high real in-line transmission >30% measured over an angular aperture of at most 0.5° at a sample thickness of 0.8 mm and with a monochromatic wavelength of light ?, preferably, of 645 nm.

Abstract: Transparent polycrystalline sintered ceramic of cubic crystal structure. The invention relates to the field of technical ceramic and relates to transparent polycrystalline sintered ceramics of cubic crystal structure for applications with increased mechanical stress, e.g., as protective or armoring ceramic. Provided are sintered ceramics that combine a high transmission of RIT>75% of the theoretical maximum value with a distinctly improved hardness. Transparent polycrystalline sintered ceramics of cubic crystal structure with a real in-line transmission RIT>75% of the theoretical maximum value measured on 0.8 mm-thick polished plates and for light of a wavelength between 600 and 650 nm, and with an average grain size D in the range of 60 nm<D<10 ?m are provided.

Abstract: The invention relates to oxide ceramic fiber composite materials that, e.g., according to the invention, are used in energy conversion installations. The present invention discloses a fundamentally new concept for the previously incompatible requirements of improved brittle fracture behavior to secure thermal shock stability and damage tolerance in the temperature range of <1000° C. and of mechanical high-temperature stability to guarantee long-term form stability (creep resistance) of components.

Abstract: Transparent polycrystalline sintered ceramic of cubic crystal structure. The invention relates to the field of technical ceramic and relates to transparent polycrystalline sintered ceramics of cubic crystal structure for applications with increased mechanical stress, e.g., as protective or armoring ceramic. Provided are sintered ceramics that combine a high transmission of RIT>75% of the theoretical maximum value with a distinctly improved hardness. Transparent polycrystalline sintered ceramics of cubic crystal structure with a real in-line transmission RIT>75% of the theoretical maximum value measured on 0.8 mm-thick polished plates and for light of a wavelength between 600 and 650 nm, and with an average grain size D in the range of 60 nm<D<10 ?m are provided.

Abstract: The invention relates to the field of technical ceramics and specifically relates to a method of synthesis for aluminum oxides of different crystalline structure and to the products obtained by the method. The aim of the invention is to provide a method of producing redispersible nanoparticulate corundum and nanoporous Al2O3 sintered products, the method using precursors and being viable on a commercial scale. To this aim, inter alia, a method of producing redispersible nanoparticulate corundum of an average particle size of D50<100 nm is used which method includes the addition of crystal nuclei. According to the method, organic or chlorine-free inorganic precursors are dissolved or processed to a sol and hydrolyzed. The substance is then dried and calcinated at temperatures of between 350 and 650° C. and is then further heated by increasing the temperature to ?950° C.

Abstract: The invention relates to oxide ceramic fiber composite materials that, e.g., according to the invention, are used in energy conversion installations. The present invention discloses a fundamentally new concept for the previously incompatible requirements of improved brittle fracture behavior to secure thermal shock stability and damage tolerance in the temperature range of <1000° C. and of mechanical high-temperature stability to guarantee long-term form stability (creep resistance) of components.

Abstract: The present invention relates to a porous aluminum oxide structure comprising Al2O3 and Zr, the structure having an open porosity greater than about 30% and an average pore size from about 20 nm to about 1000 nm, wherein the Zr, expressed as ZrO2, has a concentration less than about 5 weight % of the weight of the Al2O3.

Abstract: The present invention relates to a porous aluminum oxide structure comprising Al2O3 and Zr, the structure having an open porosity greater than about 30% and an average pore size from about 20 nm to about 1000 nm, wherein the Zr, expressed as ZrO2, has a concentration less than about 5 weight % of the weight of the Al2O3.

Abstract: An economical process for the manufacture of a polycrystalline, sintered, ceramic abrasive from a powder raw material is described, which process is characterized by the following process steps: preparation of a slip largely free from polymerizing and/or coagulating additives from the powder raw material; pressureless shallow casting of the slip in a vessel; degassing, drying and crushing of the cast sheet to obtain a fabricated material and sintering of the fabricated material to create the abrasive. This process can be used to manufacture an abrasive that permits extremely high grinding performance due to its extraordinary density and structural integrity.

Abstract: The invention relates to the field of ceramics and concerns sintered Al.s2 O.sub.3 compositions produced from corundum powder and also methods for the use of the invented compositions as medical implants or tool material. To produce such materials, an initially unsintered precursor having a relative density of .rho..gtoreq.55% is produced from .alpha.-Al.sub.2 O.sub.3 powder having defined properties using at least two different dispersing methods, this precursor is subsequently subjected to heat treatment and sintering.