Abstract: A continuous hydrothermal synthesis method which comprises pressurizing and heating a material slurry below a saturated vapor temperature or pressurizing a material slurry at normal temperature, pressurizing and heating an aqueous liquid above the saturated vapor temperature, atomizing and mixing the slurry and the aqueous liquid, effecting hydrothermal synthesis in a reaction section above the saturated vapor temperature, cooling the reaction product and taking out the product while retaining the pressurized state in the system by alternately opening and closing shut-off valves provided above and below a product discharging section or through a thin pipe provided in the product discharging section. The method is performed using an apparatus comprising heating-pressurizing sections respectively connected to a material slurry feeding section and an aqueous liquid feeding section, an atomizing-mixing section and a reaction section provided after these feeding sections, and a product discharging section.

Abstract: An anti-reflection film is arranged by alternately stacking a plurality of high-refractive index layers containing Al.sub.2 O.sub.3 and a plurality of low-refractive index layers containing SiO.sub.2 on a transparent substrate in turn from the substrate side to the air side, and satisfies:1.45.ltoreq.ns.ltoreq.1.651.60.ltoreq.na.ltoreq.1.850.31.lambda.0.ltoreq.d1.ltoreq.0.42.lambda.00.38.lambda.0.ltoreq.d2.ltoreq.0.45.lambda.00.20.lambda.0.ltoreq.d3.ltoreq.0.31.lambda.00.18.lambda.0.ltoreq.d4.ltoreq.0.28.lambda.00.20.lambda.0.ltoreq.d5.ltoreq.0.30.lambda.00.20.lambda.0.ltoreq.d6.ltoreq.0.30.lambda.0where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with the wavelength range from 190 nm to 250 nm, di (unit: nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and .lambda.

Abstract: The present invention relates to particulate compositions having improved thermal conductivity values. An embodiment of the present invention is a particulate composition which under a 103421 Pa load, at 20.degree. C., and at a pressure (P) within the range of 133.322-13332.2 Pa, in Nitrogen, has: a packing density of less than or equal to 160 kg/m3, and a Thermal Conductivity (TC) at 133.322-1333.22 Pa of less than or equal to (0.260 lnP+4.53) milliWatt/meterK (mW/m.multidot.K) and a TC at 1333.22-13332.2 Pa of less than or equal to (0.824 lnP+0.47) mW/m.multidot.K. A preferred particulate composition is a gel composition. Also disclosed are insulation bodies comprising the particulate compositions.

Abstract: New thermally- and hydrothermally-stable .delta.-alumina compositions stabilized with an oxide of silicon, germanium, phosphorus, arsenic or a mixture thereof and methods of preparation of same are provided. Also provided are catalyst supports and catalysts made using these stabilized .delta.-alumina compositions, methods for making same, and methods for treating the exhaust gas from an internal combustion engine using such catalysts.

Abstract: A low pressure combustion flame method for the production of nanophase powders, coatings and free-standing forms. The process involves controlled thermal decomposition of one or more metalorganic precursors in a flat-flame combustor unit in which both temperature distribution and gas phase residence time are uniform over the entire surface of the burner. It is this feature that makes the combustion flame reactor such a versatile tool for (1) high rate production of loosely agglomerated nanoparticle powders with controlled particle size and distribution, (2) uniform deposition of shape conformal nanophase coatings, and (3) net-shaped fabrication of nanocrystalline free-standing forms such as sheets, rings and drums. Applications for this new nanomaterials processing technology include electrical, thermal, optical, display, magnetic, catalytic, tribological and structural materials.

Abstract: An alumina-zirconia sintered body comprising 92 to 35% by weight of aluminum oxide and 8 to 65% by weight of zirconium oxide having mainly tetragonal system, and 0.2 to 5 parts by weight of silicon oxide per 100 parts by weight of the total of aluminum oxide and zirconium oxide, and having a relative density of 95% or more, has improved wear resistance and suitable for use in an impact grinder.

Abstract: This invention relates to a process for the preparation of an inorganic oxide gel comprising contacting at least one fluorinated inorganic oxide precursor with a fluorinated gelling agent in the presence of at least one fluorinated solvent to form a solution; allowing sufficient time for gelation to occur; and isolating the inorganic oxide gel. Gels made by this process are useful as coatings and as components in inorganic/organic hybrid materials.

Abstract: Process for the production of aluminium hydroxide by digesting bauxite with alkali solution and precipitating aluminium hydroxide from the digestion solution, comprising:a combining bauxite and alkali solution having a caustic concentration of at least 180 grams per liter expressed as sodium carbonate and digesting partly the bauxite in the combined product in a first digestion step at relatively low temperature,b separating reaction product obtained in step a into a liquid phase and a solids/liquid slurry,c combining liquid phase and solids/liquid slurry obtained in step b and digesting the combined product in a second digestion step at relatively high temperature,d releasing heat from the reaction product obtained in step c to preheat liquid phase obtained in step b,e separating the reaction product obtained in step d into a supersaturated sodium aluminate solution and undissolved material,f precipitating aluminium hydroxide from the supersaturated sodium aluminate solution obtained in step e and separating

Abstract: A gas phase process for the production of titanium dioxide powders having well-controlled crystalline and surface area characteristics is disclosed. In this process, which is preferably carried out in a laminar diffusion flame reactor, vapor phase TiCl.sub.4 and oxygen are mixed in a reaction area which is heated externally. The titanium dioxide powder formed is then collected. It is preferred that the heat source used be a hydrocarbon fueled (e.g., methane) flame. Optionally, a vapor phase dopant (such as SiCl.sub.4) may be added to the reaction mixture to desirably affect the physical properties of the titanium dioxide produced. In a particularly preferred embodiment, a corona electric field is positioned across the area where the combustion reaction takes place (i.e., the reaction area). High anatase, high surface area titanium dioxide powders made by this process are excellent photocatalysts. The products of this process and the use of those products as photocatalysts are also disclosed.

Abstract: A synthetic chalcoalumite compound represented by the formula (1)(Zn.sub.a-x.sup.2+ M.sub.x.sup.2+)Al.sub.4.sup.3+ (OH).sub.b (A.sup.n-).sub.c.mH.sub.2 O (1)whereinM.sup.2+ represents at least one of Cu, Ni, Co and Mg;a represents 0.3<a<2.0;x represents 0.ltoreq.x<1.0;b represents 10<b<14;A.sup.n- represents one or two selected from SO.sub.4.sup.2-, HPO.sub.4.sup.2-, CO.sub.3.sup.2-, CrO.sub.4.sup.2-, SiO.sub.3.sup.2-, NO.sub.3.sup.2-, OH.sup.- and Cl.sup.- ;c represents 0.4<c<2.0 andm represents a number of 1 to 4,and a process for the production thereof.

Abstract: A process for the agglomeration of powder or dust of alumina containing material (herein referred to as "alumina powder"), wherein an aqueous slurry of the alumina powder is formed, the slurry containing a sufficient quantity of an inorganic binder comprising a polymer form of a hydroxy salt of aluminum. The slurry is subjected to a spray drying operation to form agglomerated granules of the alumina powder, and the granules then are calcined at an elevated temperature for their consolidation. The alumina containing material comprises Al.sub.2 O.sub.3.nH.sub.2 O, wherein n is in the range of from 0 to 3.

Abstract: A method for preparing an oxide (P), which includes the steps of (i) forming a solid phase compound (O) based on an oxide containing molecular entities (1) chosen from optionally substituted ammonium, diammonium, diazan-ium or diazandium, the entities being distributed within the solid matrix, and (ii) eliminating the entities (1) from the solid phase compound (O) by reacting the solid phase compound (O) with a gaseous stream containing a break-down reactant for the entities (1), and isolating the resulting solid material (P).

Abstract: An alumina sintered body containing, as impurities, sodium oxide, potassium oxide, silicon oxide, calcium oxide, ferric oxide and titanium oxide in a total amount in the range from 100 to 10000 ppm, in which a total amount of the sodium oxide and potassium oxide based on the total amount of the impurities is not more than 4 wt. %. In the manufacture of the sintered body, its starting powder is admixed with at least an acid compound to produce metal salts by a reaction of the acid compound with metals contained in the starting powder and the resulting metal salts are removed.

Abstract: A method of making activated alumina including the steps of dissolving a double salt of aluminum in a solution of pure water at 85.degree. C., recrystalizing the double salt at a pressure about 250 psi and temperature ranging from 200.degree. C. to 250.degree. C., precipitating out the purified basic double salt, drying the precipitated double salt to drive off water and roasting it at 850.degree. C. to 950.degree. C. to drive off the sulfate, washing to remove the potassium sulfate and then drying the remaining alumina to yield activated alumina for use as a high-grade catalyst.

Abstract: A method for producing a metal oxide powder which comprises heating a metal or metals in an atmosphere gas comprising a halogen gas, a hydrogen halide gas or a mixture of these gases in a concentration of from 0.5% by volume or more to 99.5% by volume or less; and oxygen, water vapor or a mixture of these gases in a concentration of from 0.5% by volume or more to 99.5% by volume or less.

Abstract: A method for flocculation of red mud in Bayer Process streams utilizing a fatty acid or fatty acid ester free latex polymer flocculant. Preferred fatty acid free emulsifiers useful for the preparation of such flocculants are obtained by reacting ethylene and/or propylene oxide with a reagent selected from the group consisting of ethylene diamine, ethanol and ethylene glycol.

Abstract: In the present invention, alumina is produced by a process comprising leading a starting aqueous slurry containing a seed alumina hydrate to a circulating system, the aqueous slurry being circulated and returned to the starting aqueous slurry, wherein an aqueous solution of an aluminum salt and an aqueous solution of a neutralizer are added to the aqueous slurry being circulated and mixed together at a pH value of 6 to 11 to thereby cause the aqueous slurry to contain formed alumina hydrate prior to the return to the starting aqueous slurry.

Abstract: A novel gelation-resistant alumina and process for producing such a product and aqueous slurries composed thereof are disclosed, including grinding aluminum oxide of .alpha.-Al.sub.2 O.sub.3 in the presence of about 0.5 to 3.0 wt. % water. The grinding preferably is performed in a sealed ball mill. Dual phase alumina particles have an aluminum oxide inner core of .alpha.-Al.sub.2 O.sub.3 and an aluminum oxide hydroxide outer phase of .gamma.-AlOOH on the .alpha.-Al.sub.2 O.sub.3, including to a nominal depth, e.g., by way of example, of about 5 to 100 nanometers on the inner core of .alpha.-Al.sub.2 O.sub.3, and having up to 40% higher surface area than the initial aluminum oxide of .alpha.-Al.sub.2 O.sub.3. The novel gelation-resistant alumina can be dispersed in an aqueous slurry having a solids content of 65 wt. % and higher, and the resulting slurry has significantly extended shelf life.

Abstract: A composition of zirconyl hydroxy chloride and aluminum chlorhydroxide in stable solid form having improved antiperspirant efficacy when dissolved in water is made by heating a 2-20% by weight aqueous solution containing at least the aluminum chlorhydroxide component of the composition at a temperature of at least 50.degree. C. until the ratio of the height of peak 4 at Kd=0.7 to that of peak 3 at Kd=0.5 as measured by gel permeation chromatography on cross-linked dextran is at least 2:1, then subjecting the solution to rapid drying to solid form.

Abstract: A method for producing phase-pure, monodispersed, single crystal alpha-alumina particles of controlled size and shape comprises the steps of providing an aluminum hydrous oxide precursor and a glycol solution, dispersing said precursor in said glycol solution to create a suspension, heating and stirring said suspension in a closed pressure vessel to produce alpha-alumina particles, cooling said suspension, and removing said alpha-alumina particles from said solution. Additionally nucleation seeds may be added to the solution. Control of size is a function of seeding concentration, and control of morphology is a function of stirring rate.

Abstract: An alumina sol having an alumina solid content of at least 10 wt % and a viscosity of not higher than 5 Pa.s measured by a Brookfield viscometer and containing a cation other than a hydrogen ion in a total ion equivalent concentration in the range of from 2.0.times.10.sup.-4 to 1.0.times.10.sup.-1 N and a method of preparing the same.

Abstract: Reaction spray process for preparing inclusion pigments by suspending the pigment to be encapsulated in an aqueous solution or suspension of a precursor of the inclusion material, spraying the suspension, with or without the addition of nitric acid and fuel, in a tubular reactor heated at from 850.degree. to 1100.degree. C., separating the inclusion pigment from the product stream and, if desired post-calcining the pigment at a temperature of at least 816.degree. C.

Abstract: A process for significantly improving the physical properties of formed particles is disclosed. The process includes adding an effective amount of an acid stable surfactant or an alkaline stable surfactant to a component of the material before drying the particles. The preferred particles are microspheroidal for use in fluid bed reactors, but can include granules and beads.

Abstract: A flaky substrate which is characterized by a uniform small thickness, a smooth nearly colorless surface, a large aspect ratio, and a very little tendency toward crystal twinning and aggregation, is composed of aluminum oxide and titanium oxide. The flaky substrate is used to prepare an excellent pearlescent pigment.

Abstract: The invention relates to a process for the silylation of very finely divided inorganic oxides, in which the very finely divided inorganic oxides are treated with at least one silylating agent which is relatively nonvolatile in the temperature range of the overall process, with the proviso that the relatively nonvolatile silylating agent is admixed with the very finely divided inorganic oxides as a liquid, in the form of a very finely atomized aerosol. Furthermore, the invention relates to a highly apolar, pyrogenic silica prepared by this process.

Abstract: A novel gelation-resistant alumina and process for producing such a product and aqueous slurries composed thereof are disclosed, including grinding aluminum oxide of .alpha.-Al.sub.2 O.sub.3 in the presence of about 0.5 to 3.0 wt. % water. The grinding preferably is performed in a sealed ball mill. Dual phase alumina particles have an aluminum oxide inner core of .alpha.-Al.sub.2 O.sub.3 and an aluminum oxide hydroxide outer phase of .gamma.-AlOOH on the .alpha.-Al.sub.2 O.sub.3, including to a nominal depth, e.g., by way of example, of about 5 to 100 nanometers on the inner core of .alpha.-Al.sub.2 O.sub.3, and having up to 40% higher surface area than the initial aluminum oxide of .alpha.-Al.sub.2 O.sub.3. The novel gelation-resistant alumina can be dispersed in an aqueous slurry having a solids content of 65 wt. % and higher, and the resulting slurry has significantly extended shelf life.

Abstract: Dry milling an alpha alumina precursor produces direct conversion to alpha alumina at room temperature.

Abstract: The present invention provides a method for producing ceramic fine particles comprising the steps of supplying gaseous starting materials or starting material droplets to a reaction space arranged in an annular portion between inner and outer cylinders of a coaxial, double-cylinder reaction apparatus, the reaction apparatus having a stationary outer cylinder and a rotatable inner cylinder; and subjecting the gaseous starting materials or the starting material droplets to reaction in the reaction space while rotating the inner cylinder. Also, the present invention provides a production apparatus used therefor.

Abstract: An improved process for making aluminoxanes by the addition of water to a solvent solution of a hydrocarbylaluminum compound and/or an aluminoxane feeds the water through an orifice which is surrounded by a flow of solvent which carries the water into the solvent solution of hydrocarbylaluminum compound and/or aluminoxane.

Abstract: A process for preparing stabilized alumina having increased surface area retention at high temperature in which a gel of a boehmite alumina which has been obtained by hydrothermally treating an aqueous mixture of a precursor boehmite alumina having a pH of from about 5 to about 9 for a period of time sufficient to convert the greater portion of the precursor boehmite alumina to a colloidal sol is subjected to working as, for example, by using a sufficient shearing force for a sufficient period of time to produce a worked boehmite alumina which has an increase in pore volume of at least about 30 percent and an increase of median pore radius of at least about 20 percent, a stabilizer being added to the boehmite alumina, the stabilizer being an oxide of a metal such as barium or a metal included in the lanthanide series of metals or a compound of such metals which converts to an oxide at elevated temperatures.

Abstract: A composition of zirconyl hydroxy chloride and aluminum chlorhydroxide in stable solid form having improved antiperspirant efficacy when dissolved in water is made by heating a 2-20% by weight aqueous solution containing at least the aluminum chlorhydroxide component of the composition at a temperature of at least 50.degree. C. until the ratio of the height of peak 4 at Kd=0.7 to that of peak 3 at Kd=0.5 as measured by gel permeation chromatography on cross-linked dextran is at least 2:1, then subjecting the solution to rapid drying to solid form.

Abstract: A process for producing strong, essentially dust-free agglomerates from dust created by an industrial operation carried out, for example, on an ore or mineral, e.g. during the thermal conversion of a material containing predominantly gibbsite to sub-alpha alumina by a multistage thermal process having at least one intermediate stage. The process comprises grinding particles of binder material containing undercalcined alumina to a median particle size of less than 30 microns and to a specific surface area in the range of 90-300 m.sup.2 /g; combining about 1-4 parts by weight of the dust with one part by weight of the ground binder material to form combined solids; mixing the combined solids with water to produce agglomerates, the total amount of added water being about 0.8-1.2 parts by weight for every part by weight of the ground binder material, plus about 0.08 to 0.

Abstract: A process for producing .alpha.-alumina powder comprising .alpha.-alumina single crystal particles, the process comprising the step of calcining at least one of transition alumina and a transition alumina precursor capable of becoming transition alumina on heating, in a gas atmosphere containing (1) at least about 5% by volume, based on the total gas atmosphere, of a halogen selected from fluorine, chlorine, bromine, and iodine, (2) at least about 1% by volume, based on the total gas atmosphere, of a hydrogen halide selected from hydrogen fluoride, hydrogen bromide, and hydrogen iodide, or (3) a component prepared from at least about 1% by volume, based on the total gas atmosphere, of a halogen gas selected from fluorine gas, bromine gas, and iodine gas, and at least about 0.1% by volume, based on the total gas atmosphere, of steam.

Abstract: A process for making high porosity boehmite alumina comprising forming an aqueous dispersion of a boehmite alumina which has been obtained by hydrothermally treating an aqueous mixture of a precursor boehmite alumina at a pH of from about 5 to about 9 for a period of time sufficient to convert the greater portion of the precursor boehmite alumina to a colloidal sol, treating the dispersion of the hydrothermally treated alumina to form a viscous gel and subjecting the gel to sufficient shearing force for a sufficient period of time to increase the pore volume by at least 30% and the median pore radius by at least 20%.

Abstract: Polyhedral .alpha.-alumina particles having a particle size on the order of a micrometer and high purity are prepared by maintaining a compression molded aluminum material having, on its surface, a binary compound of aluminum and oxygen atoms or a ternary compound of aluminum, oxygen and hydrogen atoms in an aluminum melt.

Abstract: A process for preparing borosilicate, aluminosilicate, or phosphosilicate comprising preparing a mixture of SiCl.sub.4 with a specific molar ratio of BCl.sub.3, AlCl.sub.3, or PCl.sub.3 ; cooling said mixture to zero degrees; and adding water to the reaction mixture until the evolution of gas is complete. These silicates are useful for purifying DNA wherein the DNA is bound in water or low salt buffers (i.e., in the absence of a chaotropic agent or alcohol).

Abstract: There is provided a process for the production of a transition alumina by thermally decomposing an aluminum sulfate wherein the thermal decomposition is carried out under an atmosphere comprising a reducing substance, and the transition alumina produced by the process has a specific BET surface are of not smaller than 400 m.sup.2 /g.

Abstract: Disclosed herein is a process for producing fine metal oxide particles comprising the step of heat-treating an aqueous solution of a metal salt at a temperature of not lower than 200.degree. C. under a pressure of not less than 160 kg/cm.sup.2 for 1 second to 1 hour so as to bring into the decomposition reaction of said metal salt.

Abstract: The present invention provides a process for the production of a K- or Rb-.beta."- or -.beta.-aluminum oxide powder preparation, wherein a cubic densely packed aluminum oxide (.gamma.-aluminum oxide) or a precursor thereof is subjected to attrition together with a doping material or a precursor thereof, the so obtained mixture is calcined in an oxygen-containing atmosphere, potassium oxide or rubidium oxide or a precursor of these compounds is added to the calcination product obtained, the mixture is subjected to attrition and then calcined in an oxygen-containing atmosphere at a temperature greater than 900.degree. C. The present invention also provides a process for the production of a ceramic formed body in which a powder obtained by the above process is converted by attrition, isostatic pressing and sintering into a ceramic formed body. Such a ceramic formed body can be used as an ion conductor.

Abstract: Aluminum hydroxide containing no coarse particle is prepared by continuously supplying at least one compound selected from the group consisting of aluminum alkoxides and aluminum alkoxide derivatives which are prepared by chemically modifying aluminum alkoxides, and water under high shear rate stirring.

Abstract: A method for producing alumina-silicon carbide ceramic powders by in situ production of silicon carbide particles by introducing a pyrolyzable carbon source, preferably a gaseous hydrocarbon, into a reactor containing an alumino-silicate, pyrolyzing the pyrolyzable carbon source to form carbon particles in situ, wherein the carbon particles are capable of reacting with a silicate in the alumino-silicate to form carbide products, and then reacting the silicate and the carbon particles in situ at an effective temperature, preferably at least 1450.degree. C. and more preferably at least 1500.degree. C., for a sufficient time to transform the alumino-silicate and the pyrolyzable carbon source into the composite ceramic powder having alumina (Al.sub.2 O.sub.3) and silicon carbide (SiC) as major phases.

Abstract: A process for production of a fine alpha-alumina powder having a specific surface area of not smaller than 10 m.sup.2 /g and superior polishing characteristics is provided, the process comprising heat-treating a mixture of gamma-alumina powder and silica at a temperature at which gamma-alumina is converted to alpha-alumina in the presence of silica, wherein the mixture contains not more than about 10 wt % of silica, based on the weight of the gamma-alumina.

Abstract: An apparatus provides high temperature and short residence time conditions for the production of nanoscale ceramic powders. The apparatus includes a confinement structure having a multiple inclined surfaces for confining flame located between the surfaces so as to define a flame zone. A burner system employs one or more burners to provide flame to the flame zone. Each burner is located in the flame zone in close proximity to at least one of the inclined surfaces. A delivery system disposed adjacent the flame zone delivers an aerosol, comprising an organic or carbonaceous carrier material and a ceramic precursor, to the flame zone to expose the aerosol to a temperature sufficient to induce combustion of the carrier material and vaporization and nucleation, or diffusion and oxidation, of the ceramic precursor to form pure, crystalline, narrow size distribution, nanophase ceramic particles.

Abstract: A method of manufacture including bringing seed and aluminum hydroxide together in an aqueous medium and hydrothermally digesting for producing boehmite at the expense of the aluminum hydroxide is described. Also disclosed is a process for forming a ceramic body from colloidal boehmite and alpha alumina. Alpha alumina is added to ultimately produce a seeded gel containing microcrystalline boehmite, the seeded gel capable of being sintered at a low temperature to produce a ceramic product. The colloidal boehmite may be purified by ion exchange to remove alkali metal ions.

Abstract: A process for the preparation of nanophase solid state materials having crystallite morphology and particle sizes in the range of from about 1 nm to 30 nm is disclosed. Novel nanophase solid state materials are also disclosed.

Abstract: The invention relates to a partially crystalline, transitional aluminum oxide containing 4-fold and 5-fold coordinated aluminum oxide in a ratio of at least 1:2. The invention also relates to a method of making this composition. The composition is particularly useful as starting material for manufacturing highly reactive molded articles. Accordingly, the invention also relates to this manufacturing process.

Abstract: Fine flaky boehmite particles which have an orthorhombic crystal form and a specified crystal face grown in the form of a flat plate, and a process for the preparation of fine flaky boehmite particles which comprises subjecting aluminum hydroxide or hydrated alumina having a particle size adjusted to the order of submicrons to hydrothermal treatment in water or an aqueous alkali solution at a temperature of 150.degree. C. or above under a pressure of 100 atm or below. The fine flaky boehmite particles are useful as a starting material for the preparation of fine flaky alumina particles or as a filler suitable for a pigment for coating materials, a filler for rubbers and plastics and a coating material for paper making.

Abstract: The present invention is a barium-containing alumina with the X-ray pattern of the FIGURE. The alumina may be synthesized by simultaneously adding a polyether or a polyalcohol and an aqueous solution of a water soluble barium carboxylate to an aqueous boehmite sol or suspension to form a gel, the gel having a polyether or polyalcohol content of about 2 wt. % to about 26 wt. %, preferably about 10 wt. % to about 20 wt. %. The gel is then dried and calcined to convert it to an essentially pure barium-containing delta alumina. The alumina may be optionally hydrothermally treated to induce further crystallization. The final product contains about 2 wt. % to about 18 wt. % Ba, preferably about 8 wt. % to about 12 wt. %.

Abstract: Filamentary abrasive particles formed from a sol-gel alumina modified by rare earth metal oxides have excellent abrasive qualities.

Abstract: Submicron sized ceramic particles are produced by combining a ceramic precursor with an organic or carbonaceous carrier material, and exposing droplets of the mixture to a temperature sufficient to cause combustion of the organic material and subsequent vaporization and nucleation, or diffusion and oxidation, of the ceramic precursor to form pure, crystalline, uniform nanophase ceramic particles.