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: A boehmite particulate material is disclosed. The material is formed by a process that includes providing a boehmite precursor and boehmite seeds in a suspension, and heat treating the suspension to convert the boehmite precursor into boehmite particulate material. The boehmite particulate material has an aspect ratio of not less than 3:1.

Abstract: A sol gel formulation and process for making thick coatings. In accordance with the teachings of this invention, sol gel coating layers of up to 300 microns in thickness can be provided in a single deposition.

Abstract: The invention concerns an additive-containing ground calcined alumina used as constituent of a refractory material precursor characterized in that it comprises an organofunctional silane, the organic function being typically an epoxy function, an alkyl function, an alcohol function or a diol function. Preferably said organofunctional silane is an oxyranyl-alkyl-silane, of chemical formula C9H20O5Si. Said additive-containing alumina can be obtained by adding said organofunctional silane during grinding to take advantage of its anti-caking properties, the intimate and homogeneous mixture being obtained as a result of grinding. It may also result from a post-grinding mixing.

Abstract: A process is disclosed for forming a nanosize ceramic powder. A precursor ceramic material is formed of a fugitive constituent and a non-soluble constituent in a single phase. The precursor is contacted with a selective solvent (water, acid, etc.) to form a solution of the fugitive constituent in the solvent and a residue of the non-soluble constituent. The precursor is sufficiently reactive with the solvent to form the solution of the fugitive constituent in the solvent and form the nondissolved residue of the non-soluble constituent. The precursor material and the non-soluble residue are sufficiently insoluble in the solvent such that there is insufficient precursor material and non-soluble residue in solution to deposit and precipitate upon the residue of the non-soluble-constituent.

Abstract: The present invention provides &agr;-alumina powders comprising &agr;-alumina particles of which at least 80% of the &agr;-alumina particles have a particle size of less than 100 nm. The invention also provides slurries, particularly aqueous slurries, which comprise &agr;-alumina powders of the invention. The invention further provides methods of manufacturing &agr;-alumina powders and &agr;-alumina slurries of the invention and methods of polishing using same.

Abstract: A method for producing an &agr;-alumina powder is described. The method for producing an &agr;-alumina powder comprises a step of calcining an aluminum salt in the presence of a seed crystal at 600-890° C.

Abstract: This invention concerns intercalation compounds and in particular lithium intercalation compounds which have improved properties for use in batteries. Compositions of the invention include particulate metal oxide material having particles of multicomponent metal oxide, each including an oxide core of at least first and second metals in a first ratio, and each including a surface coating of metal oxide or hydroxide that does not include the first and second metals in the first ratio formed by segregation of at least one of the first and second metals from the core. The core may preferably comprise LixMyNzO2 wherein M and N are metal atom or main group elements, x, y and z are numbers from about 0 to about 1 and y and z are such that a formal charge on MyNz portion of the compound is (4−x), and having a charging voltage of at least about 2.5V.

Abstract: A method of producing fine particles of an oxide of a metal, comprising the steps of: preparing an acidic solution which contains ions of the metal; precipitating fine particles of a hydroxide of the metal by adding an alkaline solution to the acidic solution; collecting the fine particles of the hydroxide of the metal precipitated in a mixed solution of the acidic solution and the alkaline solution; mixing fine particles of a carbon with the collected fine particles of the hydroxide of the metal; and heat-treating a mixture of the fine particles of the hydroxide of the metal and the fine particles of the carbon at a predetermined temperature in a non-reducing atmosphere, whereby the fine particles of the oxide of the metal are produced.

Abstract: This invention relates to crystalline boehmitic aluminas the crystallites of which exhibit unusual dimensional differences in the space directions 020 and 120. This invention further relates to a method for preparing such aluminas and the follow-up products obtained therefrom by calcination.

Abstract: The invention provides alumina agglomerates of the type obtained by dehydrating an aluminum hydroxide or oxyhydroxide, agglomerating the alumina obtained, hydrothermally treating the agglomerates and calcining, characterized in that:

Abstract: Thermally stable transitional alumina particulates retaining high specific surface area after calcination at 1000° C. suitable for the use as catalysts or catalysts supports are produced by treating an aqueous solution containing Al3+ and optionally a doping amount of La3+ (e.g., 0.3 mol. %) with an anion-exchange resin to give a stable hydroxide sol followed by freeze drying of the sol and further thermal dehydration. The resultant stabilized transitional alumina retains high specific surface area at 1000° C., and additionally stabilization is achieved at very low levels of added La.

Abstract: The present invention relates to a single step process for the synthesis of nanoparticles of phase pure ceramic oxides of a single or a multi-component system comprising one or more metal ions. The process comprises preparing a solution containing all the required metal ions in stoichiometric ratio by dissolving their respective soluble salts in an organic solvent or in water, preparing a precursor, adjusting the nitrate/ammonia content in the system, and heating the system.

Abstract: The present invention relates to polycrystalline alumina ceramics having low transition metal impurities and methods for producing the same.

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: The invention relates to an abrasive grain containing electro-fused alumina, formed of crystals of hexagonal structure less than 100 &mgr;m in size, preferably less than 30 &mgr;m, and further preferably less than 5 &mgr;m, having a density that is greater than 97%, preferably 98%, of the theoretical density of alumina and a Knoop hardness of more than 2000.

Abstract: A process for producing a solid acid catalyst, which comprises: adding a pseudoboehmite as a binder to a sulfated zirconium hydroxide, followed by kneading with an aqueous solution containing at least one metal of the Group VIII, or loading at least one metal of the Group VIII on a sulfated zirconium hydroxide, and then adding a pseudoboehmite as a binder thereto, followed by kneading with water, further followed by molding and calcining at a temperature of from 550 to 800° C.; a solid acid catalyst produced by the production process; and a method for hydrodesulfurizing and isomerizing a light hydrocarbon oil using the catalyst.

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: The production and selection of precursor mixtures used to produce fine powders and methods for making fine powders using the selected precursor. The precursor mixture comprises at least one metal containing precursor, the metal containing precursor has an average molecular weight of less than 2000 grams per unit mol of the metal, the metal containing precursor has a normal boiling point greater than 350K, and the viscosity of the precursor mixture is between 0.1 to 250 cP. The precursor mixture is processed under conditions that produce a fine powder from the precursor mixture. Fine powders produced are of size less than 100 microns, preferably less than 10 micron, more preferably less than 1 micron, and most preferably less than 100 nanometers.

Abstract: The present invention concerns a novel, highly dispersible aluminium hydrate. It also concerns a process for preparing said aluminium hydrate by precipitation of an aluminium hydrate in a reactor with no back-mixing and preparation of said aluminium hydrate in a reactor with back-mixing. Finally, it concerns the use of said hydrate for the preparation of catalysts or catalyst supports.

Abstract: A method for producing fine or ultra fine powder particles comprising mixing a metal alkoxide with a non-metallic hydride in an organic solvent, agitating the mixed solution, and then burning the mixed solution. The burning process comprises igniting the solution directly or burning the solution in situ. A self-sustaining flame will result. When the precursor solution burns, the metallic compound will be co-fired with the organic solvent. As a result, fine or ultra fine particles of mixed metal will burst from the flame, or thrust through the flame and be synthesized.

Abstract: Dispersions of pyrogenic oxides, doped using an aerosol, are prepared by mixing the oxide with a suspending agent and milling. The dispersions can be used to prepare inkjet paper.

Abstract: The present invention pertains to cheaper process for the preparation of quasi-crystalline boehmite containing additive in a homogeneously dispersed state. In this cheaper process an inexpensive quasi-crystalline boehmite precursor is and additive are combined and aged to form a quasi-crystalline boehmite containing additive in a homogeneously dispersed state. Suitable inexpensive quasi-crystalline boehmite precursors are aluminum trihydrate and thermally treated forms thereof and inorganic aluminum salts. Suitable additives are compounds containing elements selected from the group of rare earth metals alkaline earth metals, transition metals, actinides, silicon, gallium, boron, and phosphorus.

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: A dielectric material having a high dielectric constant includes a Group III metal oxide and a Group V element. The incorporation of the Group V element in the Group III metal oxide material reduces the number of structural defects in the dielectric material, and reduces both the fixed charge density and the conduction current of the dielectric material.

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: Method for producing metal oxide nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone into metal vapor. The metal vapor is directed away from the hot zone and into the cooler plasma afterglow where it oxidizes, cools and condenses to form solid metal oxide nanoparticles.

Abstract: Bismuth- and phosphorus-containing catalyst supports, naphtha reforming catalysts made from such supports, methods of making both support and catalyst, and a naphtha reforming process using such catalysts.

Abstract: The present invention relates to a metal oxide powder for high precision polishing and prepartion thereof, comprising aggregates formed by cohesion of primary particles, which has a cohesive degree (&agr;) of 1.1 to 2.

Abstract: A dispersion of alumina hydrate comprises an alumina hydrate containing 0.1 to 1.0% by weight of a nitrate anion and having an average pore radius of 20 to 200 Å and a half breadth of pore radius distribution of 20 to 150 Å and deionized water. Another dispersion of alumina hydrate comprises an alumina hydrate containing 0.1 to 1.0% by weight of a nitrate anion and having at least two peaks in pore radius distribution and deionized water. Another dispersion of alumina hydrate comprises a titanium dioxide-containing alumina hydrate containing 0.1 to 1.0% by weight of a nitrate anion and deionized water. In each of these dispersions, when the alumina hydrate is dispersed in water at a solids concentration of 15% by weight to form a dispersion, the viscosity of the dispersion is not higher than 75 cP as measured at 20° C. and the dispersion has a shear rate of 7.9 sec−1.

Abstract: Nanoscale, pyrogenically produced oxides and/or mixed oxides having a BET surface area of between 1 m2/g and 600 m2/g and a chloride content of less than 0.05 wt. % are produced by converting organometallic and/or organometalloid substances into the oxides at temperatures of above 200° C. The oxides may be used as a polishing agent in the electronics industry (CMP).

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 calcined alumina, its production method and fine a alumina powder obtained by using the calcined alumina are described. The calcined alumina has the SET specific surface area of 10 to 20 m2/g, the main crystal phase of &agr; phase, a &thgr; phase not substantially contained, and the average particle size of 0.5 &mgr;m or less. The method for producing the calcined alumina comprising calcining an aluminum-containing substance containing substantially no metal element other than aluminum in an atmosphere having a partial pressure of water vapor of 600 Pa or less. The fine &agr;-alumina powder having a purity of 99.99% or more and a BET specific surface area of 15 m2/g or more, containing substantially no transition alumina, and providing, when calcined at 1250° C. under normal pressure, a sintered body having a relative density of 95% or more.

Abstract: The present invention pertains to an improved process for the preparation of quasi-crystalline boehmite. In this improved process a quasi-crystalline boehmite precursor is aged at a pH below 7, prefereably under hydrothermal conditions. It was found that when conducting the preparation processes for quasi-crystalline aluminas described in the prior art at a pH below 7 and under hydrothermal conditions instead of the high pH and thermal aging used in the prior art, QCBs with higher crystallinity are obtained. In the process according to the invention additives may be added to the quasi-crystalline boehmite precursor. This results in a high quality QCB with additives in a homogeneously dispersed state. Suitable additives are compounds containing elements selected from the group of rare earth metals alkaline earth metals, transition metals, actinides, silicon, gallium, boron, and phosphorus.

Abstract: A method for fabricating electrically conductive silicon carbide articles by doping and sintering submicron silicon carbide particles using sub-micron alumina as the dopant source. Submicron alumina particles are made by milling aluminum powder. Despite the ductility of metallic aluminum, it is successfully ball milled in an aqueous medium through the creation and abrasion of successive layers of an alumina skin to yield alumina particles as small as 0.01 &mgr;m across. When suitably composed mixtures of the silicon carbide and alumina are molded into a green body and heated sufficiently in a non-oxidizing furnace atmosphere, the alumina breaks down to metallic aluminum which diffuses into the silicon carbide. The small particle sizes and the presence of a sintering aid enable rapid processing kinetics which favor saturation of the silicon carbide by the aluminum and inhibit grain growth.

Abstract: A process is disclosed for the treatment of an alumina process feedstock prior to transferring the treated feedstock to an alumina process for extracting refined alumina from the treated feedstock. The treatment process includes the following steps: (a) heating the alumina process feedstock to a temperature of 400C. to 650C. by direct contact with combustion gases, and (b) cooling the heated feedstock to a temperature at which it can be handled and fed to the alumina process. The treatment process is characterised by controlling the contact time of the solid alumina process feedstock at temperatures in the above range in step (a) to less than 5 minutes.

Abstract: Doped, pyrogenically prepared oxides of metals and/or non-metals which are doped with one or more doping components in an amount of 0.00001 to 20 wt. %. The doping component may be a metal and/or non-metal or an oxide and/or a salt of a metal and/or a non-metal. The BET surface area of the doped oxide may be between 5 and 600 m2/g. The doped pyrogenically prepared oxides of metals and/or non-metals are prepared by adding an aerosol which contains an aqueous solution of a metal and/or non-metal to the gas mixture during the flame hydrolysis of vaporizable compounds of metals and/or non-metals.

Abstract: The invention relates to an abrasive grain based on electromelted alumina consisting of crystals with a hexagonal structure, of size less than 100 &mgr;m, and preferably less than 30 &mgr;m, and more preferably less than 5 &mgr;m, with density higher than 97%, preferably 98%, of the theoretical density of alumina, and a Knoop hardness higher than 2000. The invention also relates to a method for making abrasive grains based on alumina consisting in melting alumina, casting it at a constant flow rate less than 80 kg/mn, and cooling it by dispersing the melted alumina in fine droplets to obtain articles with size less than 1 mm. The dispersion is preferably performed by ultrasound-assisted spraying, at a frequency ranging between 15 and 50 MHz. The inventive grains are used in particular for making grindstones.

Abstract: The selectivity and activity of a silver-based olefin epoxidation catalyst is found to be a function of the pore size distribution in the alumina carrier on which it is deposited. Specifically it is found advantageous to provide a carrier which has a minimum of very large pores, (greater than 10 micrometers) and a water absorption of 35 to 55% and a surface area of at least 1.0 m2/g. A method of making such carriers is also described.

Abstract: A method for making alumina having a pore structure characterized by the absence of macropores, no more than 5% of the total pore volume in pores greater than 350 Å, a high pore volume (greater than 0.8 cc/g measured by mercury intrusion) and a bi-modal pore volume distribution character, where the two modes are separated by 10 to 200 Å, and the primary pore mode is larger than the median pore diameter (MPD), calculated either by volume or by surface area, the MPD by volume being itself larger than the MPD by surface area. Alumina made by such process and catalyst made therefrom.

Abstract: The present invention is directed to a process for the preparation of crystalline anionic clay-containing bodies from sources comprising an aluminum source and a magnesium source comprising the steps of: a) preparing a precursor mixture, b) shaping the precursor mixture to obtain shaped- bodies, c) optionally thermally treating the shaped bodies, and d) aging to obtain crystalline anionic clay-containing bodies. The quintessence of the present invention is that the bodies are shaped prior to the forming of the crystalline anionic clay in said bodies. This results in very attrition resistant bodies, without the need to add a binder material.

Abstract: The present invention provides particulate alumina having a mean particle size corresponding to a volume-cumulative (50%) mean particle size (D50) of 1.5 to 4 &mgr;m and a ratio (D90/D1O) of D90 to D10 of 2.5 or less. The alumina contains secondary particles having a particle size of at least 10 &mgr;m in an amount of 0.1 mass % or less; secondary particles having a particle size of 0.5 &mgr;m or less in an amount of 5 mass % or less; and an &agr;-phase as a predominant phase.fluoride. The present invention also provides a method for producing the particulate alumina.

Abstract: Granules based on aluminium oxide having the characteristics: 1 Average grain diameter: 5.

Abstract: A process is provided for the treatment of an alumina process feedstock prior to transferring the treated feedstock to an alumina process for extracting refined alumina from the treated feedstock. The treatment process includes: (a) heating the alumina process feedstock to a temperature of 400° C. to 650° C. by direct contact with combustion gas, and (b) cooling the heated feedstock to a temperature at which it can be handled and fed to the alumina process. The treatment process also includes controlling the contact time of the alumina process feedstock at temperatures in step (a) to ensure decomposition of alumina trihydrate and alumina monohydrate. The process also includes: (i) limiting the maximum temperature of incoming gas to a stage of the process in which the alumina process feedstock reaches the above temperature range of 400° C. to 650° C.

Abstract: The present invention provides an &agr;-alumina powder, which is suitable for use as a filler for silicon rubber or the like for manufacturing a heat-conductive sheet. The &agr;-alumina powder includes &agr;-alumina particles having an average particle diameter of not less than about 2 &mgr;m and not more than about 5 &mgr;m, a particle size distribution such that a ratio of 90 wt % diameter D90 to 10 wt % diameter D10 represented by D90/D10 is not more than about 2, and a crystalline form represented by an index A of more than about 0.40 and not more than about 0.50, wherein the index A is obtained by substituting X-ray intensities I(110), I(300) and I(116) at (110) plane, (300) plane and (116) plane, respectively, determined by X-ray diffraction, into the following formula (I): A={I(110)+I(300)}/{2×I(116)}  (I).

Abstract: The method of preparing the porous material incorporating ultrafine metal particles comprises the following steps: (1) preparing surface-protected ultrafine metal particles by reducing metal ions in the presence of molecules such as dodecanethiol molecules; (2) immersing a wet gel in a solution of the ultrafine metal particles, thus forming an ultrafine metal particle/wet gel composite in which the ultrafine metal particles are incorporated in the wet gel; and (3) drying the ultrafine metal particle/wet gel composite to form a porous body.

Abstract: This invention relates to a method of producing an alumina porous material using a mixed powder of alumina powder and aluminum hydroxide represented by the chemical formula Al(OH)3 at different percentages as the starting material, comprising the steps of heating this mixed powder to decompose the aluminum hydroxide and further heat treating it within a temperature range of 1,000 to 1,600° C., and to the alumina porous material produced by the above-mentioned method with a porosity exceeding 40 volume % and its specific surface area of 8 to 40 m2/g, and further to a filter and catalyst carrier that are obtained using this alumina porous material.

Abstract: Aerogels having a high density of hydroxyl groups and a more uniform pore size with fewer bottlenecks are described. The aerogel is exposed to a mixture of a supercritical fluid and water, whereupon the aerogel forms a high density of hydroxyl groups. The process also relaxes the aerogel into a more open uniform internal structure, in a process referred to as hydroetching. The hydroetching process removes bottlenecks from the aerogels, and forms the hydrogels into more standard pore sizes while preserving their high surface area.

Abstract: Porous spheroidal alumina particulate solids that comprise an alumina filler in an amount of about 0.1% to about 25% by weight of Al2O3 and have a mechanical resistance to shocks measured by spheres impacting against a target at the speed of 20 m/s such that the fines fragmentation percentage, of a size of less than 50% of the average size of the initial spheres, is less than 5% by weight. Preparation of these spheres by coagulation in drops from an oil-in-water-type emulsion. Application of these spheres as a catalyst substrate or as an adsorbent.

Abstract: A microcrystalline boehmite containing additive in a homogeneously dispersed state. Suitable additives are compounds containing elements selected from the group consisting of alkaline earth metals, alkaline metals, rare earth metals, transition metals, actinides, silicon, gallium, boron, titanium, and phosphorus. The microcrystalline boehmite according to the invention may be prepared in several ways. In general, a microcrystalline boehmite precursor and an additive are converted to a microcrystalline boehmite containing the additive in a homogeneously dispersed state. The additive does not contain zirconia or magnesia.