Abstract: A high-chromium refractory material that provides improved resistance to coal slag penetration is presented. The refractory mixture comprises a blend of chromium oxide, aluminum oxide and phosphates. The refractory mixture may be blended with an aggregate and cured. In addition a phosphorous oxide may be blended with chromium oxide and aluminum oxide and additionally an aggregate. The refractory mixture reduces the rate of coal slag penetration into the surface of the cured refractory.

Abstract: The object of the present invention is to provide a refractory having sufficient corrosion resistance against alkali vapors and excellent thermal shock resistance which is light in weight and suitable for glass tank furnaces. The present invention provides a high-alumina fused cast refractory comprising from 94 to 98% of Al2O3, from 1 to 6%, in total, of Na2O and/or K2O, which is mainly composed of &agr;-Al2O3 crystals and &bgr;-Al2O3 crystals, has pores dispersed in it and has a porosity of from 5 to 30%.

Abstract: Compositions, articles and methods for making such articles are disclosed. The compositions, articles and methods include calcium aluminate materials having a low coefficient of thermal expansion.

Abstract: The present invention provides nanoporous &agr;-alumina powders comprising powder comprising interconnected &agr;-alumina primary particles having an average particle size of less than about 100 nm and an interpenetrated array of pores or voids. The invention also provides nanosized &agr;-alumina powders comprising &agr;-alumina particles having an average particle size of less than about 100 nm and slurries, particularly aqueous slurries, which comprise nanosized &agr;-alumina powders of the invention. The invention further provides methods of manufacturing nanoporous &agr;-alumina powders and nanosized &agr;-alumina powders of the invention and methods of polishing using slurries of the invention.

Abstract: A method for producing an &agr;-alumina particulate is described.

Abstract: An object of the present invention is to provide a transparent ceramics which exhibits favorable slope efficiency well comparable to that of a single crystal when employed in solid lasers, yet having a uniform quality and internally free from pores, foreign matters, or granular structures. Another object of the present invention is to provide a production method therefor. The above problems have been overcome by a transparent YAG—ceramics (YAG: Y3Al5O12) the physical properties thereof is improved by doping a metallic element, provided that the concentration of the doped metallic elements is in a range of from 0.1 to 20% by weight, that the concentration of nitrogen is 500 ppm or lower, that said ceramics has pores and foreign matters accounting for less than 100 mm2 per 100 cm3 as expressed by their projected area, and that it has an internal transmittance for visible radiations of 50 %/cm of higher. The metallic element for doping the YAG—ceramic is Nd.

Abstract: High-density composites of ceramic materials, notably alumina or metal oxides in general, are formed by the incorporation of metal particles, of which niobium is a preferred example, and single-wall carbon nanotubes. The composites demonstrate an unusually high fracture toughness compared to the ceramic alone, and also when compared to composites that contain either the metal alone or single-wall carbon nanotubes alone. The two additives thus demonstrate a synergistic effect in improving the toughness of the ceramic.

Abstract: A ceramic material suitable for use in production of paving tiles, construction tiles, flooring in offices, flooring in machinery plants and so forth is obtained by a method comprising steps of mixing defatted bran derived from rice bran with a thermosetting resin before kneading, subjecting a kneaded mixture thus obtained to a primary firing in an inert gas at a temperature in a range of 700 to 1000° C., pulverizing the kneaded mixture after the primary firing into carbonized powders, kneading the carbonized powders with which ceramic powders, a solvent, and a binder as desired are mixed into a plastic workpiece (kneaded mass), pressure-forming the plastic workpiece at pressure in a range of 10 to 100 MPa, and subjecting a formed plastic workpiece thus obtained again to firing in an inert gas atmosphere at a temperature in a range of 100 to 1400° C.

Abstract: Ceramic mass and thermal transfer media suitable for use in thermal regenerative oxidizers made using a mixture of a ball clay, talc and optionally a dolomitic limestone have enhanced resistance to environments containing halogens and hydrogen halides. The media preferably comprises less than 0.25% by weight of alkali metal, expressed as the oxide, and has a cordierite: silica phase ratio of less than 1.2:1, as determined by X-ray diffraction.

Abstract: An oxide ceramic material is provided to contain aluminum oxide as a principal component, and at least one selected from A and B shown below as an auxiliary component:

Abstract: An object of the present invention is to lower the sintering temperature required for a sintered body of yttrium-aluminum garnet, to improve the corrosion resistance of the sintered body and to prevent the reduction of the transmittance thereof. A sintered body of yttrium-aluminum garnet is produced from a source compound for yttrium and a source compound for aluminum using aluminum nitride as a sintering aid. It maybe considered that aluminum nitride reacts with alumina and yttria to generate liquid phase and to reduce the sintering temperature during the sintering process.

Abstract: The present disclosure describes improved compositions comprising an agitating agent, the compositions being particularly useful for powder injection molding. The disclosed method includes protocols for extracting binder materials from a powder injection molding prior to sintering. One embodiment of the disclosure includes compositions comprising a sinterable powder, a binder and a gas-forming agent. When induced to release a gas, the gas-forming agent provides internal agitation, which facilitates solvent-based binder extraction, resulting in a higher yield of extracted binder in reduced time. In one embodiment, the compositions include a carbonate, such as sodium carbonate, as the gas-forming agent. In this embodiment, the gas-forming agent is induced to form a gas during binder extraction by including an acid, such as citric acid, in the extraction solvent.

Abstract: Composite oxide powder has a large specific surface area and a large pore volume even after a high-temperature durability test, without losing oxygen storage ability of a single metal oxide. In this composite oxide powder, a first metal oxide having oxygen storage ability is held as ultrafine particles in the form of islands by a second metal oxide which is different from the first metal oxide, pore volume is not less than 2 cc/g and the first metal oxide particles have a diameter of not more than 30 nm even after subjected to high temperature of 900° C. or more. Since the first metal oxide particles are held in the form of islands by the second metal oxide particles, separated from each other and suppressed from contacting each other, the first metal oxide particles hardly grow granularly.

Abstract: The invention relates to a method of producing a dental prosthesis, comprising the steps:

Abstract: An improved lightweight and highly permeable proppant composition for use in increasing the productivity of a gas or oil well. The proppant composition includes equal amounts by weight of uncalcined bauxite, uncalcined shale and quartz, held together with a binder formed of wollastonite and talc in an amount of less than 10% by weight of the composition. The proppant composition has an alumina content of less than 25% by weight of the composition and a silica content of over 45% by weight of the composition.

Abstract: A sintered alumina ceramic obtained by preparing a raw material powder mixture containing alumina and a Group 3A metal oxide or a Group 3A metal compound which provides a Group 3A metal oxide on heating, and firing said raw material powder mixture. The sintered ceramic contains alumina particles having an average particle diameter of 4.0 &mgr;m or smaller. In the sintered ceramic, the total content of alkali metal elements, alkaline earth metal elements, Si, and Ti as converted to oxides accounts for 0.1 mol or less with respect to 100 mols of alumina, the total peak intensity for the principal peaks for ReAlO3 and Re3Al5O12 (Re: Group 3A metal) amounts to from 1 to 75% of the intensity of the principal peak of alumina as measured by X-ray diffraction, and the relative density is 99.0% or higher with respect to the theoretical density.

Abstract: The present invention pertains to injectable heat generating biocompatible ceramic compositions based on hydraulic calcium aluminate, which can be used for therapeutic treatment in vivo, such as tumour treatment, pain control, vascular treatment, drug activation etc, when curing in situ, and which form a biocompatible solid material that can be left in the body for prolonged periods of time without causing negative health effects. The present invention can also be used to restore the mechanical properties of the skeleton after cancerous diseases.

Abstract: The disclosed invention relates to novel crystalline compositions which may be obtained by doping the alpha (&agr;) form of AlPO4 ceramics, which find use as piezoelectric materials, stable supports for catalysts, biotechnology uses, and the like.

Abstract: Monazite or xenotime-based blanket coatings that stiffen ceramic fabrics without causing embrittlement at temperatures of at least as high as 2400° F. are provided. Methods for making the coatings are also provided. The methods comprise the synthesis of high purity, monazite and xenotime powders with the stoichiometric ratio of metal to phosphorous of about 1:1.

Abstract: Methods of producing doped and undoped yttrium aluminum garnet and yttrium aluminum perovskite containing powders and the powders produced thereby are provided. Additionally, methods of forming doped and undoped polycrystalline yttrium aluminum garnet having a mean grain size of between about 1 &mgr;m to about 3 &mgr;m and the yttrium aluminum garnet produced thereby are provided. The doped and undoped polycrystalline yttrium aluminum garnet may be formed by sintering a compact and subsequently hot isostatically pressing the compact.

Abstract: Granules based on aluminium oxide having the characteristics: Average grain diameter: 5.0 to 150 &mgr;m Tamped density: 300 to 1200 g/l The granules are produced by dispersing aluminium oxide in water, performing spray drying, optionally heat treatment and/or silanization. In silanized form, the granules have the following characteristics: Average grain diameter: 5 to 160 &mgr;m Tamped density: 300 to 1200 g/l Carbon content: 0.3 to 12.0 wt. % The granules are used inter alia as catalyst supports, in cosmetics, in toner powders, in paints and lacquers, as abrasives and polishing agents and as a raw material in the production of glass and ceramics.

Abstract: This invention concerns a non-basic refractory batch as well as its use.

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: A method of manufacturing a phosphate-bonded refractory product entirely during the mixing cycle by reacting phosphoric acid and alumina derived from one or more sources of finely divided reactive alumina, for example &bgr;-alumina and/or alumina hydroxide to form a proto aluminum orthophosphate gel or paste binder in the pan of a high-intensity mixer at ambient temperatures.

Abstract: An alumina-based composite sintered material comprising alumina as a main ingredient and containing one or more carbonitridation products of groups IVa, Va and VIa of the periodic table and/or two or more carbonitridation products of solid solutions of groups IVa, Va and VIa of the periodic table. The content of nitrogen solid solute in the carbonitridation product increases from the interior to the surface of the sintered material, and the Vickers hardness at the surface of the sintered material is 19.5 GPa or more.

Abstract: Crack-free alumina honeycombs of high strength and high surface area are made from anhydrous alumina powder extrusion batches incorporating a combination of a hydrous aluminum oxide or aluminum hydroxide permanent binder and a polymeric aluminum salt; extruded honeycombs incorporating these constituents plus temporary binders, peptizing aqueous acid additions and water exhibit significantly reduced drying shrinkage, and thus reduced cracking, high fired surface area, and high fired strength.

Abstract: Porous ceramics are described, which are produced by a) mixing an aqueous solution of a suitable ionotropically orientable polyanion, either with oxides, hydroxides or hydrated oxides, which are present in the form of a sol, of the metals Al, Zr, Ti and Nb, or with finely crystalline oxides, hydroxides or hydrated oxides, which are present in suspension, of these metals, or with finely crystalline tricalcium phosphate or apatite which are present in suspension, b) bringing the mixed sol obtained as in a) or the suspension obtained as in a) into contact with a solution of a salt of a di- or trivalent metal cation in order to produce an ionotropic gel body, c) compacting the gel body by introducing it into electrolyte solutions which further enhance the syneresis of the polyelectrolyte which was originally formed, d) washing the gel body with water and subsequently impregnating it with a readily volatile, water-miscible solvent, e) freeing the anhydrous gel body or gel bodies obtained as in d) from the

Abstract: An aluminum titanate-based ceramic article having a composition comprising u (Al2O3-TiO2)+v (R)+w (3Al2O3-2SiO2)+x (Al2O3)+y (SiO2)+z (1.1SrO-1.5Al2O3-13.6SiO2-TiO2)+a (Fe2O3-TiO2)+b (MgO-2TiO2), where, R is SrO-Al2O3-2SiO2 or 11.2SrO-10.9Al2O3-24.1SiO2-TiO2, where u, v, w, x, y, z, a and b are weight fractions of each component such that (u+v+w+x+y+z+a+b=1), and 0.5<u≦0.95, 0.01<v≦0.5, 0.01<w≦0.5, 0<x≦0.5, 0<y≦0.1, 0<z≦0.5, 0<a≦0.3, and 0<b≦0.3. A method of forming the ceramic article is provided. The ceramic article is useful in automotive emissions control systems, such as diesel exhaust filtration.

Abstract: A method for making an aluminum oxide (Al2O3) component utilizes an amount of aluminum oxide in particle form. The aluminum oxide initially has less than about 100 parts per million of sodium and less than about 600 parts per million of silica. The aluminum oxide is ground with media that comprise aluminum oxide ceramic pieces that have less than about 200 parts per million of sodium to deagglomerate and reduce the particle size of the aluminum oxide. The ground aluminum oxide is placed into a slurry, and a low sodium grade binder is added to the slurry. The slurry is dried to provide an aluminum oxide powder having a sodium content that is less than about 200 parts per million. The powder may then be formed into a certain shape and thermally treated to produce an aluminum oxide component having a low sodium and low silica content.

Abstract: A microstructured or nanostructured multi-component ceramic comprises (a) a major ceramic phase comprising a ceramic oxide composite; (b) a ceramic oxide additive; and (c) a rare earth ceramic oxide additive, wherein the total of the additives (b) and (c) comprise from about 0.1 weight percent to less than 50 weight percent based on the total weight the multi-component ceramic composite. In another embodiment, a microstructured or nanostructured multi-component ceramic comprises (a) a major ceramic oxide phase comprising a ceramic oxide composite; and either (b) a ceramic oxide additive or (c) a rare earth ceramic oxide additive, wherein amount of the additive (b) or (c) comprises from about 0.1 weight percent to less than 50 weight percent based on the total weight the multi-component ceramic composite. Such ceramics are useful as bulk materials or as feedstocks for thermal spray.

Abstract: A ZrO2—Al2O3 composite ceramic material having high mechanical strength and toughness as well as excellent wear resistance and hardness is provided. This ceramic material includes a first phase of ZrO2 grains containing 10 to 12 mol % of CeO2 as a stabilizer and having an average grain size of 0.1 &mgr;m to 1 &mgr;m, and a second phase of Al2O3 grains having an average grain size of 0.1 to 0.5 &mgr;m.

Abstract: Blocks of material are prepared in a variety of shapes and sizes to be used in the fabrication of models for dental restorations. The material comprises a partially sintered ceramic material. The blocks are used to manufacture molds using CAD/CAM methods and equipment. The molds are useful in the manufacture of dental restorations using ceramics, metals, alloys, or powders thereof, and composite materials. The models milled from the blanks may be used to manufacture a variety of dental restorations including, but not limited to, crowns, bridges, space maintainers, tooth replacement appliances, orthodontic retainers, dentures, posts, jackets, inlays, onlays, facings, veneers, facets, implants, abutments, splints, partial crowns, teeth, cylinders, pins, and connectors.

Abstract: Compositions, articles and methods for making such articles are disclosed. The compositions, articles and methods include calcium aluminate materials consisting essentially of a main phase of CaAl4O7 and having a low coefficient of thermal expansion produced by utilizing an additive and firing to temperatures below about 1600°0 C.

Abstract: The invention is directed at a mullite-aluminum titanate porous diesel particulate filter constituting a porous ceramic body containing, expressed in terms of weight percent of the total body, of 60-90%, preferably 70-80%, most preferably 70% iron-aluminum titanate solid solution having a stoichiometry of Al2(1−x)Fe2xTiO5, where x is 0-0.1, and 10-40%, preferably 20-30%, most preferably 30% mullite (3Al2O3.2SiO2), and consists essentially, expressed in terms of weigh percent on the oxide basis, of 3 to 15% SiO2, 55 to 65% Al2O3, 22 to 40% TiO2, and 0 to 10% Fe2O3, and being useful for filtration of diesel exhaust. The inventive diesel particulate filter exhibits high interconnected open porosity and large median pore size, in combination with high permeability when fired to a temperature of between 1650° to 1700° C., along with high thermal shock resistance and good filtration capability.

Abstract: A method of producing alumina having a low soda content and excellent sintering properties includes the steps of adding a soda removal agent to alumina source material and calcining the alumina source material in a calciner (2), using a dust collector (5) to collect calcined alumina source material dust contained in the exhaust gas, discharging a portion of the collected dust out of the system, slurrying another portion of the collected dust in a slurrifier (10) while controlling slurry pH, washing and filtering the slurried dust and recirculating it back to the calciner, recirculating still another portion of the collected dust together with a mineralizing agent to the calciner, and removing the low soda alumina after the calcination.

Abstract: Sintered alumina of Q value of greater than 25,000 and up to and greater than 45,000 at 10 GHz and at 25° C., useful in useful in dielectric resonators can be obtained by sintering alumina powders with low level of impurities at between 1500° C. and 1600° C. until a density of at least 98% of its theoretical value is obtained.

Abstract: A process for producing roundish alumina particles includes heating at 1,000 to 1,600° C. a composition containing at least one of electrofused alumina and sintered alumina having a mean particle size greater than 35 &mgr;m, and at least one species selected from the group consisting of a halogen compound, a boron compound and an alumina hydrate; and crushing the composition.

Abstract: A method of manufacturing aluminum-substituted hematite represented by &agr;-(Fe1−xAlx)2O3 where x=0.01 to 0.15, by mixing an iron compound and an aluminum compound such that an atomic ratio of Fe to Al falls within the range of 99:1 to 85:15, adding citric acid and ethylene glycol to the mixture of the iron compound and aluminum compound to produce a gel, and pyrolyzing the gel, followed by calcining the pyrolyzed product.

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: A ceramic support element for a NOx trap which includes a NOx storage component comprising an alkali metal, the ceramic support having a composition lying within a ternary system selected from the group consisting of Al2TiO5—MgTi2O5—MgAl2O4 and Al2TiO5—FeTiO5—Al2O3, a coefficent of thermal expansion (22-800° C.) of less than 20×10−7/° C. and a modulus of rupture as measured on a solid rod of circular cross section of greater than 1000 pounds per square inch.

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 colonies. The fused abrasive particles can be incorporated into abrasive products such as coated abrasives, bonded abrasives, non-woven abrasives, and abrasive brushes.

Abstract: Compositions, articles and methods for making such articles are disclosed. The compositions, articles and methods include calcium aluminate materials having a low coefficient of thermal expansion.

Abstract: Disclosed herein is a method to produce ceramic materials utilizing the sol-gel process. The methods enable the preparation of intimate homogeneous dispersions of materials while offering the ability to control the size of one component within another. The method also enables the preparation of materials that will densify at reduced temperature.

Abstract: There is provided a treatment container which enables to prolong a period of time taken for reaction products, such as a halide generated through reaction with corrosive halide gas, to exfoliate and fall down as particles, and decreases the frequency of periodic maintenance operation, thereby implementing increase of operating time. The treatment container constituting a chamber or a bell jar has a portion of the inner surface to be exposed to corrosive halide gas plasma and is formed with a sintered body mainly composed of a compound of yttrium and aluminum with oxygen, and the portion has a roughened surface of a mean roughness Ra of 1.5 to 10 &mgr;m.

Abstract: An erosion resistant member that may be used in the processing of a substrate in a plasma of a processing gas, comprises at least a portion that may be exposed to the plasma of the processing gas and that contains more than about 3% by weight of an oxide of a Group IIIB metal. The portion may also further contain a ceramic compound selected from silicon carbide, silicon nitride, boron carbide, boron nitride, aluminum nitride, aluminum oxide, and mixtures thereof.

Abstract: An arc tube is formed by polycrystalline alumina so that an average crystal grain diameter of a surface is two to ten times as large as an average crystal grain diameter of an inside including a center line of a thickness and the average crystal grain diameter on the center portion of the thickness is 10 &mgr;m to 100 &mgr;m. As a result, in the arc tube, the total transmittance is 98%, and a linear ray transmittance is 5%.

Abstract: A plasma fluorine resistant polycrystalline alumina ceramic material is produced by forming a green body including alumina and a binder, and sintering the green body for a time from about 8 to 12 hours. The area % of unsintered particles in the polycrystalline alumina ceramic material does not exceed 0.1 area %, resulting in reduced emission of particles from the material after exposure to plasma fluorine.

Abstract: A ceramic composite containing alkali-metal-beta- or beta″-alumina and an oxygen-ion conductor is fabricated by converting alpha-alumina to alkali-metal-beta- or beta″-alumina. A ceramic composite with continuous phases of alpha-alumina and the oxygen-ion conducting ceramic, such as zirconia, is exposed to a vapor containing an alkali-metal oxide, such as an oxide of sodium or potassium. Alkali metal ions diffuse through alkali-metal-beta- or beta″-alumina converted from &agr;-alumina and oxygen ions diffuse through the oxygen-ion conducting ceramic to a reaction front where alpha-alumina is converted to alkali-metal-beta- or beta″-alumina. A stabilizer for alkali-metal-beta″-alumina is preferably introduced into the &agr;-alumina/oxygen-ion conductor composite or introduced into the vapor used to convert the alpha-alumina to an alkali-metal-beta″-alumina.

Abstract: Particles particularly useful for thermal spraying a wear resistant coating on to a substrate comprise an essentially single phase crystalline structure comprising from 45 to 100% by weight of chromia and from 0 to 55% by weight of alpha alumina.