Abstract: A freeze-forging method for producing sintered three-dimensional ceramic bodies, particularly magnesium aluminate spinel domes. The method comprises forming a ceramic mix of a ready-to-sinter ceramic powder and a nonaqueous liquefied sublimable vehicle having a solidification temperature from room temperature to below 200° C.; reducing the temperature of the ceramic mix to below the vehicle's solidification temperature to freeze the mix; crushing the frozen mix into powdered form; cold forging the frozen powder in a mold to form a solidified green body of the desired three-dimensional shape; and densifying the green body into a sintered three-dimensional ceramic body.

Abstract: Methods of making and compositions of dense sintered ceramic nano- and micro-composite materials that are highly stable in a variety of conditions and exhibit superior toughness and strength. Liquid feed flame spray pyrolysis techniques form a plurality of nanoparticles (e.g., powder), each having a core region including a first metal oxide composition comprising Ce and/or Zr or other metals and a shell region including a second metal oxide composition comprising Al or other metals. In certain aspects, the core region comprises a partially stabilized tetragonal ZrO2 and the shell region comprises an ?-Al2O3 phase. The average actual density of the ceramic after sintering is greater than 50% and up to or exceeding 90% of a theoretical density of the ceramic.

Abstract: The invention relates to a material for the formation of protective layers resistant to high temperatures on chromium oxide forming substrates, to a manufacturing method and to a use of these materials. It is suitable for a use as a chromium evaporation layer for metallic alloys containing chromium in the high temperature range. It is the object of the invention to provide a material for applications as a protective layer for chromium oxide forming alloys of high temperature resistance which is thermally and mechanically permanently stable and ensures a high electrical conductivity at the operating temperature of the fuel cell. In accordance with the invention, the material is formed from a spinel phase and an oxidic secondary phase which is preferably formed with an oxidic compound containing manganese.

Abstract: A spinel sintered body has a composition of MgO·nAl2O3 (1.05?n?1.30) containing 20 ppm or less of Si element. A production method thereof includes the steps of: forming a compacted body from a spinel powder containing 50 ppm or less of Si element and having a purity of not less than 99.5 mass %; a first sintering step of forming a sintered body having a density of not less than 95% by sintering the compacted body at 1500° C. to 1700° C. in a vacuum; and a second sintering step of subjecting the sintered body to pressurized sintering at 1600° C. to 1800° C.

Abstract: Disclosed are high-porosity cordierite honeycomb substrates having fine pore size, narrow pore size distribution, little or no microcracking, and a high thermal shock resistance. The porous ceramic honeycomb substrates generally include a primary cordierite ceramic phase as defined herein. Also disclosed are methods for making and using the cordierite substrates.

Abstract: The optical elements for ultraviolet radiation, especially for microlithography, are made from cubic granet, cubic spinel, cubic perovskite and/or cubic M(II)- as well as M(IV)-oxides. The optical elements are made from suitable crystals of Y3Al5O12, Lu3Al5O12, Ca3Al2Si3O12, K2NaAlF6, K2NaScF6, K2LiAlF6 and/or Na3Al2Li3F12, (Mg, Zn)Al2O4, CaAl2O4, CaB2O4 and/or LiAl5O8, BaZrO3 and/or CaCeO3. A front lens used in immersion optics for microlithography at wavelengths under 200 nm is an example of a preferred optical element of the present invention.

Abstract: The present invention relates to a basic-refractory composition containing magnesium orthotitanate (Mg2TiO4) and calcium titanate (CaTiO3) suitable for use in rotating kilns for the production of Portland cement or lime.

Abstract: An in-situ method for nanomixing magnesium aluminate spinel nanoparticles with a uniformly distributed controlled concentration of nanoparticles of an inorganic sintering aid, such as LiF, to produce ready-to-sinter spinel powder. The spinel-sintering aid nanomixture is formed by induced precipitation of the sintering aid nanoparticles from a dispersion of the spinel nanoparticles in an aqueous solution of the sintering aid, followed by separation, drying and deagglomeration of the spinel-sintering aid nanomixed product.

Abstract: A composition with a Mohs hardness of at least 6.0, wherein said composition contains at least 30 weight percent of spinel crystals, at least 10 weight percent of glass, and less than 10 weight percent of ferrometalsilicate. The composition also contains particles with a particle size distribution such that at least about 95 weight percent of such particles are smaller than about 2.0 millimeters; at least about 70 weight percent of such particles have a particle shape that is either the blocky particle shape or the pyramidal particle shape. At least 20 weight percent of the spinel crystals are equiaxed spinel crystals; the weight/weight ratio of said spinel crystals to said glass is at least 1.2/1; the composition has a melting point in excess of 1440 degrees Celsius; and the composition has a density of from about 3.0 to about 4.5.

Abstract: A refractory brick having durability equal to alumina-magnesia castable materials, which is especially suitable for a ladle for steel making is provided. A refractory brick prepared by using an alumina raw material and a magnesia raw material containing 90% by mass or more of a fine powder of not more than 0.5 mm, press molding and then heat treating at 100° C. or higher and not higher than 1,150° C., the refractory brick containing Al2O3 and MgO in a total sum of 90% by mass or more, from 4 to 16% by mass of MgO, from 0.5 to 5% by mass of SiO2, and Na2O and K2O in a total sum of from 0.3 to 2% by mass, with the remainder being inevitable impurities and Al2O3.

Abstract: Molten ceramic grains are intended, for example, for applications involving abrading tools, having the following average chemical weight composition, expressed in weight percent based on oxide content: Al2O3: 93% to 97.5%; MgO: 2.2 to 6.5%; SiO2: <0.1%; other impurities: <0.4%.

Abstract: The invention relates to a fired refractory ceramic product and a batch that can be used to produce said product. Both the batch (the mixture) and the prepared fired product contain spinels consisting of MgO and Al2O3.

Abstract: A ceramic having at least about 90% by weight magnesium aluminate and having a bulk scattering and absorption loss of less than about 1/cm at any wavelength in a range of about 0.23 to about 5.3 microns or 0.2/cm at any wavelength in a range of about 0.27 to about 4.5 microns. A method of making a ceramic by providing a plurality of particles having a magnesium aluminate core and a fluoride salt coating; heating the particles in an oxidizing atmosphere to a temperature in the range of about 400° C. to about 750° C.; and sintering the particles to form a solid ceramic.

Abstract: A low-cost spinel sintered body having small polarization and high heat-conductivity is provided. Also, a useful light-transmitting window and light-transmitting lens for light-emitting device is provided. For such purpose, the spinel sintered body of the present invention has a contrast ratio of 300 or more in the case of white light, where the contrast ratio is defined as the quotient obtained by dividing an amount of transmitting light in the case of being arranged between two polarizing plates, the polarizing directions of the two polarizing plates being parallel to each other, by an amount of transmitting light in the case of being arranged between two polarizing plates, the polarizing directions of the two polarizing plates being orthogonal to each other.

Abstract: Excellent characteristics concerning slag penetration-resistance, corrosion-resistance, and structural stability on usage of lining-refractory such as equipment for desiliconizing molten iron, a ladle for steel-making, a RH equipment are obtained. Unshaped refractories provide fine particles of under 0.75mm diameter, and aggregate of 0.75-10mm. Furthermore, the fine particles contain 10-35 mass % content of MgO, to the total mass % of the fine particles. Even furthermore, the sum total amount of MgO and Al2O3 is more than 90 mass %, to the total mass % of the fine particle. Additionally, such fine particles has 5-40 mass % of particles made of periclase-spinel, as a source of MgO, to the total mass % of the unshaped refractories. And, the aggregate comprises at least one selected from the group consisting of particles made of alumina and particles made of spinel.

Abstract: The invention relates to a refractory ceramic product which comprises: a) ?93% by weight of at least one refractory basic component and b) ?7% by weight of at least one anticorrosive component from the group including: b1) transition metals, b2) compounds of transition metals with each other, b3) non-oxidic compounds of transition metals, b4) oxidic compounds of transition metals, b5) compounds of the transition metals with Ca, Ba, Sr.

Abstract: The invention relates to a fired refractory ceramic product and a batch that can be used to produce said product. Both the batch (the mixture) and the prepared fired product contain spinels consisting of MgO and Al2O3.

Abstract: A nanocomposite ceramic includes a uniform combination of a ceramic spinel phase and an alumina phase, wherein each phase exhibits a grain size in the range of from about 0.1 nm to 10,000 nm.

Abstract: A refractory brick, comprised of a refractory material having about 55% to about 96% by weight magnesia particles or magnesia particles containing spinel precipitates, about 3% to about 20% by weight fine zirconia particles having a particle size less than 35 Tyler mesh (less than 425 ?m), and about 1% to about 25% of a material selected from the group consisting of coarse zirconia, coarse spinel, coarse alumina-zirconia, and combinations thereof.

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: A dense cordierite based sintered body is provided, containing at least 93% by mass of cordierite among crystal components present in the sintered body. The average particle diameter of the particles constituting the sintered body is 2 ?m or less.

Abstract: A subject for the invention is to provide an unshaped refractory composition having not only high thermal resistance but also improved corrosion resistance and improved unsusceptibility to slag infiltration. The invention is “an unshaped refractory composition comprising: (1) 20 to 70% by weight raw spinel material comprising an MgO—Al2O3 spinel phase and containing 2 to 20% by weight magnesia and/or raw spinel/corundum material comprising an MgO—Al2O3 spinel phase and a corundum phase and containing 2 to 20% by weight magnesia; (2) 3 to 12% by weight raw magnesia material having a particle diameter of 0.3 mm or smaller, containing particle sizes of 75 ?m or smaller in an amount of 55 to 85% by weight, and having a magnesia purity of 90% by weight or higher; (3) 3 to 10% by weight alumina cement having a calcia content lower than 20% by weight; (4) 0.3 to 1.5% by weight ultrafine powder consisting mainly of silica; and (5) a raw alumina material as the remainder”.

Abstract: A ceramic sintered body comprising from 90 to 99.8% by volume of cordierite and from 0.2 to 10% by volume of mullite based on 100% by weight of a total sum of the contents of the cordierite and the mullite, and having a density of 2.48 g/cm3 or more.

Abstract: A fired spinel complex oxide is produced by firing a mixture containing a slag by-produced in chromium refining, a reducer, and a silica-containing material, and is essentially composed of: 29 to 40 percent by weight of Fe2O3; 15 to 20 percent by weight of Al2O3; 9 to 14 percent by weight of MgO; 0 to 4 percent by weight of Na2O; 9 to 17 percent by weight of Cr2O3; 14 to 20 percent by weight of SiO2; and 2 percent by weight or less of CaO. The fired spinel complex oxide shows a Cu—K? X-ray diffraction pattern in which the ratio (b/a) of the diffraction peak intensity of the silica-containing material (b) in the vicinity of 2?=26.7° to the {113} plane diffraction peak intensity (a) in the vicinity of 2?=36° is 0.1 or less.

Abstract: The invention relates to a fired refractory ceramic molded piece with a spinel matrix based on (Mg)2+ (Al, Cr)23+O4, in which coarser particles based on chromium corundum and/or corundum and coarser particles based on ZrO2 are present.

Abstract: A method of preparing beta-spodumene bodies from a plastic batch comprised entirely of minerals, absent a glass component. The resulting structure has a stoichiometry of 1:1:4 (Li2O:Al2O3:SiO2) to 1:1:11 (Li2O:Al2O3:SiO2), and exhibits a low coefficient of thermal expansion, high porosity and high strength, and is suitable for automotive catalytic converter substrates requiring a fast light-off time. There is also provided a ceramic article having a solid-solution of beta-spodumene ranging in molar ratio from 1:1:4 Li2O—Al2O3—SiO2 to 1:1:11 LiO2—Al2O3—SiO2 wherein a component selected from the group consisting of magnesium oxide (MgO), manganese oxide (MnO), and cobalt oxide (CoO) is substituted for lithium oxide (LiO2) at 10 to 65 mole %, and optionally a minor phase of mullite (3Al2O3-2SiO2) in an amount of up to 50% by weight.

Abstract: A material for refractory shaped bodies or compounds, the material being a pleonaste and/or a spinel of the pleonaste type. In addition to FeOx and Al2O3, the material also includes MgO. The ratio of the iron in the material is calculated as Fe2O3:Al2O3 and ranges from 30:70 to 60:40. The material contains from 20 to 60% by mass of MgO, as based on Fe2O3+Al2O3.

Abstract: Composites of ceramic materials, notably alumina or metal oxides in general, with single-wall carbon nanotubes are consolidated by electric field-assisted sintering to achieve a fully dense material that has an unusually high fracture toughness compared to the ceramic alone, and also when compared to composites that contain multi-wall rather than single-wall carbon nanotubes, and when compared to composites that are sintered by methods that do not include exposure to an electric field.

Abstract: This invention pertains to product and process. The product is a transparent product of a density in excess 99.5% comprising spinel and having uniform mechanical properties. The process pertains to fabrication of a transparent spinel product comprising the steps of dissolving a sintering aid in water to form a neutral sintering aid solution, adding a suitable additive to the sintering aid solution, applying the sintering aid solution to spinel particles to form a spinel dispersion, sub-dividing or atomizing the spinel dispersion to form droplets comprising one or more spinel particles coated with the final spinel solution, drying the droplets to form dried coated particles comprising one or more spinel particles coated with a dried layer of the sintering aid, and densifying the dried coated particles to form a transparent spinel product having uniform optical and mechanical properties in absence of grains of exaggerated size.

Abstract: An economical and environment-friendly process for the synthesis of anionic clays with carbonate and/or hydroxide anions as the charge-balancing interlayer species is disclosed. The process involves reacting a slurry comprising an aluminum source and a magnesium source, the aluminum source comprising two types of aluminum-containing compounds, preferably aluminum trihydrate and/or thermally treated calcined aluminum trihydrate. There is no necessity to wash or filter the product. It can be spray dried directly to form microspheres or can be extruded to form shaped bodies. The product can be combined with other ingredients in the manufacture of catalysts, absorbents, pharmaceuticals, cosmetics, detergents, and other commodity products.

Abstract: A material for refractory shaped bodies or compounds, the material being a pleonaste and/or a spinel of the pleonaste type. In addition to FeOx and A12O3, the material also includes MgO. The ratio of the iron in the material is calculated as Fe2O3:Al2O3 and ranges from 30:70 to 60:40. The material contains from 20 to 60% by mass of MgO, as based on Fe2O3+Al2O3.

Abstract: The invention relates to a fired refractory ceramic molded piece with a spinel matrix based on (Mg)2+ (Al, Cr)23+O4, in which coarser particles based on chromium corundum and/or corundum and coarser particles based on ZrO2 are present.

Abstract: A material for refractory shaped bodies or compounds, the material being a pleonaste and/or a spinel of the pleonaste type. In addition to FeOX and Al2O3, the material also includes MgO. The ratio of the iron in the material is calculated as Fe2O3:Al2O3, and ranges from 30:70 to 50:40. The material contains from 20 to 60% by mass of MgO, as based on Fe2O3+Al2O3.

Abstract: Ceramics comprising filler crystal particles having an average particle diameter of not smaller than 2.5 &mgr;m and a matrix crystal phase present on the grain boundaries of the filler crystal particles, the filler crystal particles being Al2O3 and the matrix crystal phase being diopside-type oxide crystals precipitated from the crystallized glass. The ceramics has a dielectric loss tangent at 60 to 77 GHz of not higher than 50×10−4, and can be effectively used as an insulating substrate in a wiring board for transmitting high-frequency signals.

Abstract: A light-transmitting (fluorescent) sintered body formed of specific substances different from the prior art materials, solving problems that the performance or efficiency, uses and manufacturing methods are limited which have not been solved with the prior art light-transmitting sintered body and which provides a light-emitting tube and an electric discharge lamp using a light-transmitting (fluorescent) sintered body formed of the specific substance. Provided are a light-transmitting sintered body mainly formed of a compound having a Mugnetplumbite structure or a &bgr;-alumina structure except for aluminum oxide, a light-transmitting sintered body mainly formed of a compound containing rare earth elements with an ionic valence of two, aluminum element and oxygen element as main components and an light-transmitting sintered body formed of mainly of a compound containing elements with an ionic valence of two except for rare earth elements, rare earth elements and oxygen element as main components.

Abstract: A resistor, which is solidified from a melt, is provided for a refractory shaped body, and includes a refractory mineral metal-oxide main component having elasticizers a general formula A2+B3+2O4 in an amount so that solubility of the main component for the elasticizer is exceeded with the elasticizers providing precipitation areas in the main component. The resistor is produced by a joint melting of the main component and the oxides which form the elasticizers. A process is provided for the production of the resistor.

Abstract: Disclosed is a ceramic material which is suitable for coating a body by way of a thermal spraying method and which has a coefficient of longitudinal thermal expansion that may be matched to that of a metal. The ceramic material includes 10 to 95% by weight of MgAl2O4, 5 to 90% by weight of MgO, up to 20% by weight of Al2O3, remainder standard impurities, and has grains of MgO which are embedded in a matrix of MgAl2O4.

Abstract: An electromagnetic wave suppressor sheet formed into a sheet-like shape out of a material made of synthetic resin in which powder of conjugated magnetic particles surface-treated with an insulating inorganic material has been dispersed.

Abstract: An insulating ceramic composition includes a mixture of a ceramic powder containing MgAl2O4 and a glass powder containing 30-60% by mole of silicon oxide on the basis of SiO2 and 20-55% by mole of magnesium oxide on the basis of MgO, and the ceramic powder further includes Mg2SiO4 and TiO2. The insulating ceramic composition can be fired at 1000° C. and co-sintered with Ag and Cu. An insulating ceramic obtained by sintering the insulating ceramic composition has a high Q-factor and is therefore suitable for ceramic multilayer substrates used at high frequencies.

Abstract: This invention is a method of manufacturing oxide porous bodies and components of alumina and magnesia, using alumina and magnesia powders as raw materials, wherein (1) cold isostatic pressure (CIP) of at least 100 MPa is applied to the materials to introduce a plastic deformation with lattice disorder in the surface vicinity without external changes in the particles, (2) by sintering (calcining) the powders with the above described plastic deformation, the microscopic plastic deformation is removed and, at the same time, formation and growth of necks between grains is induced, (3) from the above described steps (1) and (2), a highly porous body with a structure constituted by a three dimensional network of grains connected through the necks is produced.

Abstract: Strong, high-surface-area honeycombs of alumina or other ceramic composition are provided by compounding and shaping a moldable ceramic powder extrusion batches including a cellulosic temporary binder and a high-surface-area boehmite precursor for a permanent binder, hydrating the shaped honeycomb to develop a boehmite binding phase, and calcining the hydrated body to develop the binder and provide a ceramic honeycomb of high strength and porosity.

Abstract: The present invention relates to a ceramic dielectric material for communication components, which can be used in the microwave and millimeter wave frequency band. More particularly, the present invention relates to a dielectric ceramic composition for the microwave/millimeter wave frequency band having a very high quality factor and a low dielectric constant, and a method of manufacturing the dielectric ceramic using the same. The dielectric ceramic composition consists of spinel (MgAl2O4) as a major component and a small amount of lithium carbonate (Li2CO3) as a sub composition with a specific composition formula. The dielectric ceramic is manufactured from magnesia (MgO), alumina (Al2O3) and lithium carbonate (Li2CO3) as raw materials and through the ceramic processing of calcination, shaping and sintering. The obtained dielectric ceramic has the quality factor (Q×f) of 160,000 and the dielectric constant (&egr;r) of 8.5.

Abstract: Fused abrasive particles comprising eutectic material comprising Al2O3—MgO-REO eutectic. The fused abrasive particles can be incorporated into abrasive products such as coated abrasives, bonded abrasives, non-woven abrasives, and abrasive brushes.

Abstract: A porosifying, solidification-accelerating additive for binding agent building materials consisting of Al2O3, 50-90%; MgO, 4-20%; SiO2, 0.5-15%; AlN, 0.1-5%; Fe2O3, 0.1-5%; CaO, 0.1-5%; F, 0.1-5%; Na2O, 0.1-5%; K2O, 0.1-2%; as well as in the form of metallic particles: Al, 0.1-10%; Si, 0.1-3%; Fe, 0.1-3%; balance in total maximum, 5%; annealing losses, 0.1-15%; and of mineral main constituents in the form of corumdum (&agr;-Al2O3) and spinel (MgO×Al2O3), wherein the metallic aluminum particles are enveloped by mineral transition modifications from aluminum hydroxide (Al2O3×3H2O) to &agr;-aluminum oxide, the powder comprises a particle size of at least 90% smaller than 500 &mgr;m, and the BET surface of the powder amounts to at least 10 m2/g.

Abstract: The present invention relates to a ceramic dielectric material for communication components, which can be used in the microwave and millimeter wave frequency band. More particularly, the present invention relates to a dielectric ceramic composition for the microwave/millimeter wave frequency band having a very high quality factor and a low dielectric constant, and a method of manufacturing the dielectric ceramic using the same. The dielectric ceramic composition consists of spinel (MgAl2O4) as a major component and a small amount of lithium carbonate (Li2CO3) as a sub composition with a specific composition formula. The dielectric ceramic is manufactured from magnesia (MgO), alumina (Al2O3) and lithium carbonate (Li2CO3) as raw materials and through the ceramic processing of calcination, shaping and sintering. The obtained dielectric ceramic has the quality factor (Q×f) of 160,000 and the dielectric constant (&egr;r) of 8.5.

Abstract: The invention relates to free-flowing refractory castable material and castings produced therefrom. Refractory nonbasic and basic refractory castable materials have been known for a long time. The traditional refractory castable materials have thixotropic properties and must be lined sing vibration technology. In the past, free-flowing refractory castable materials were solely based on alumina raw materials. Attempts to produce an aqueous, highly concentrated basic suspension which would Coma the basis of free-flowing refractory castable materials failed to meet the requirements in terms of theological properties and a low degree of to hydration of the MgO-based materials. It is the aim of the invention to provide the above-mentioned refractory castable material for the monolithic lining or repair of high-temperature equipment and for the production of refractory castings. This is achieved by providing a fine-grained and a mixed fine and coarse-grained alternative.

Abstract: The invention relates to a material for refractory shaped bodies or compounds, wherein the material is a pleonaste and/or a spinel of the pleonaste type which, in addition to FeOx and Al2O3, also includes MgO, the ratio of the iron, calculated as Fe2O3:Al2O3 ranging from 30:70 to 60:40, and the material containing from 20 to 60% by mass of MgO, based on Fe2O3+Al2O3.

Abstract: A sensor material for measuring physical parameters capable of configuring a sensor capable of directly measuring a high value of physical parameters such as high stress or high pressure without employing a pressure resistance container. The sensor material for measuring static and dynamic physical parameters includes a matrix made of an electrically insulating ceramic material, and piezoresistance materials which are dispersed in the matrix so as to be electrically continuous to each other.

Abstract: The present invention has an object to obtain a ceramic body that can support a required amount of catalyst component, without lowering the characteristics such as strength, being manufactured without forming a coating layer and providing a high performance ceramic catalyst body that is excellent in practical utility and durability.

Abstract: The invention relates to a refractory ceramic mass comprising 60 to 99 MgO sinter and 1 and 40 wt.-% of a manganese containing spinel.