Abstract: Ceramic moldings composed of aluminum oxide which have a proportion of intercrystalline fracture of more than 50%, an average pore radius of more than 4 .mu.m and a porosity of more than 2%, are obtained by:a) grinding aluminum oxide which is at least 99.5% pure and has an average primary crystal size of 1 to 4 .mu.m to an average fragment size of 2 to 7 .mu.m,b) adding a source of magnesium oxide, silicon oxide and calcium oxide in amounts such that the magnesium oxide content is 0.2 to 2.5%, the silicon dioxide content is 1 to 6% and the calcium oxide content is 0.1 to 2.5%, in each case with respect to the amount of Al.sub.2 O.sub.3,c) shaping a green compact andd) sintering.

Abstract: A granular castable refractory composition is provided which has excellent insulating properties as well as high strength and resistance to oxidation, corrosion or erosion. The refractory insulating composition can be easily transported using a pump, and avoids the potential hazards associated with asbestos and ceramic fibers. The refractory insulating composition is prepared by mixing a low density expanded granular refractory insulating material having a density of 7-50 lb/ft.sup.3 with a conventional high density refractory material having a density of at least 150 lb/ft.sup.3 to form a dry component, and by mixing the dry component with aqueous colloidal silica to provide excellent flow properties for pumping and, ultimately, excellent binding properties.

Abstract: The present invention provides an aluminium titanate ceramic composed of, as main crystalline phases, 60-85% of an aluminum titanate phase, 10-25% of a rutile phase, 2-10% of a corundum phase and 2-10% of a mullite phase, wherein the amount of vitreous phase is 5% or less. The aluminum titanate ceramic is superior in both heat cycle durability and casted property.

Abstract: There is disclosed a process for preparing porous ceramic granules, comprising(a) preparing a foam from an aqueous mixture of a particulate aluminosiliceous material and a fluxing material;(b) dividing the foam into discrete particles to form granules; and(c) calcining the granules at an elevated temperature such that sintering of the aluminosiliceous particles occurs.

Abstract: A substantially amorphous, aluminum-containing oxide having the composition Al.sub.1-x-y1-y2 Bi.sub.x M.sub.1y1 O.sub.z (wherein x is defined by 0.0001.ltoreq.x.ltoreq.0.10, M.sub.1 is at least one selected from Si, P, B, Sb, Se, Te, Sn, Zn, In, Cr, Nb, Sc, Y, Sr, Ba, Ca, Na, Li, Mg, Mn, W, Ti, Zr, Hf, Be and rare earth metals, M.sub.2 is at least one selected from Fe, Ni, Co, Rh, Ru, Re, Cu and Pb, y1 is defined by 0.ltoreq.y1.ltoreq.0.1, y2 is defined by 0.ltoreq.y2.ltoreq.0.01, z is defined by 1.2.ltoreq.z.ltoreq.1.5, and x, y1, y2 and z are each an atomic ratio); an aluminum-containing metal composition containing the above oxide and Al and/or Bi in a metallic state; a process for producing the above oxide or the above metal composition; and a molded article formed from the above oxide or the above metal composition. The above oxide or the above metal composition is useful as an electronic part, a catalyst, and the like.

Abstract: A refractory article such as a slide gate plate, well block nozzle or like refractory component used in continuous casting of chemically aggressive grades of steel is made from a mixture containing about 50-85 wt. % alumina; about 5-30 wt. % alumina-zirconia fused grain; about 3-10 wt. % zirconia; and about 3-10 wt. % silica, plus an effective amount of binder materials to permit extrusion, pressing or like forming process. The pressed shape is fired in an air atmosphere at temperatures in excess of 1000.degree. C. to form an oxide bond. The composition of the fired material comprises about 60-90 wt. % alumina; about 5-30 wt. % zirconia; and about 3-10 wt. % silica. The fired article exhibits excellent hot strength and is resistant to thermal shock and resistant to the erosive and corrosive effects of molten steel, including aggressive, high manganese and calcium treated grades.

Abstract: A method of producing an electrocast brick or other ceramic shape, and the ceramic shape produced thereby, wherein the electrocast brick or other ceramic shape is cast in a mold which is formed, with a predetermined cavity shape and size, of quartz glass particles; the ceramic material of the ceramic shape may be Al.sub.2 O.sub.3 -ZrO.sub.2 -SiO.sub.2 ceramic, Al.sub.2 O.sub.3 -SiO.sub.2 ceramic or other heat meltable ceramic materials.

Abstract: A ceramic composition and method for making ceramic composites having superior erosion and corrosion resistance to molten metal. The composite includes mullite, aluminum nitride and boron nitride in combination. The composite may be hot pressed or cold formed and pressureless sintered into a desired shape.

Abstract: Disclosed is a porous sepiolite having an improved water-resistance and thermal shock resistance obtained by grinding, moisture-conditioning and molding sepiolite, and then calcining said molded sepiolite at a temperature in the range of about 650.degree. C. to about 800.degree. C. Also disclosed is a porous sepiolite having a large specific surface area, wherein the pores having a pore diameter of 50 angstroms or less have a specific surface area in the range of from 40 to 200 m.sup.2 /g and in which no less than 20% of the total surface of the sepiolite is occupied with the pores having a pore diameter of 50 angstroms or less and wherein the pore distribution curve of the sepiolite has a main peak at a pore diameter of no more than 50 angstroms. This sepiolite is obtained by grinding, moisture-conditioning and molding sepiolite, calcining the same at a temperature in the range of about 650.degree. to about 800.degree. C., and then subjecting said calcined sepiolite to an acid treatment.

Abstract: A sintered ceramic-metal composite product has a ceramic matrix of polycrystalline ceramic in which a metal phase is dispersed for adding improved toughness. The metal phase has a higher melting point than the sintering temperature of the ceramic matrix and comprises at least one metal selected from the groups IVa, Va and VIa of the periodic table. The metal phase is dispersed intragranular within the grains of the ceramic matrix to realize nano-order dispersion of the metal phase which is responsible for remarkably improved toughness as well as strength. The ceramic-metal composite product is successfully fabricated by several unique methods utilizing the mixture of the ceramic and metal or metal oxide, hydride or alkoxide.

Abstract: A plastic or moldable composition of zeolite is obtained by adding 0.1-20 parts by weight of a .beta.-1.3-glucan, 1:1 layer-type clay mineral and 2:1 layer-type clay mineral together with an adequate amount of water to 100 parts by weight of zeolite powder, and then kneading the resultant mixture. The composition may be, for example, extrusion-molded to a honeycomb structure, and calcined, to provide a calcined article of honeycomb structure of zeolite which has a high dimensional accuracy and strength, and hence is useful as a drying agent, a catalyst or a carrier material therefor. The calcined article of zeolite has an excellent mechanical strength.

Abstract: In order to provide a rare earth oxide-alumina type sintered body having no defect such as void and pore, and high strength, toughness and reliability, silica is added to a mixture of rare earth oxide and alumina to control a crystal grain size of the sintered body to not more than 30 .mu.m, whereby abnormal grain growth and occurrence of pore are restrained to produce a practically usable rare earth oxide-alumina-silica sintered body having excellent strength and toughness and uniform structure. According to this production method, rare earth oxide-alumina-silica sintered bodies having no defect such as void and pore, and high strength, toughness and reliability can easily be obtained.

Abstract: A high alumina refractory and its preparation are disclosed. In addition to the mix of alumina particles providing an Al.sub.2 O.sub.3 content of at least 50%, by weight, there is included metallic carbide particles, having a critically-selected particle size distribution, in an amount between about 3 and about 25%, by weight, based on the total dry weight at the mixture. Other forms of carbon, like tar, pitch and graphite are omitted. The product is free from black core and has improved resistance to molten slags and metals.

Abstract: Silicon-aluminum mixed oxide powder which is flame-hydrolytically produced and has a composition of 65 to 85% by weight Al.sub.2 O.sub.3, remainder SiO.sub.2 and an amorphous structure, in which each primary particle contains components of SiO.sub.2 and of Al.sub.2 O.sub.3, the primary particles are between 7 and 80 nm, preferably 10 and 40 nm in size and the specific surface of the powder is between 20 and 200 m.sup.2 /g. The powder is used for the production of mullite and sintered compacts manufactured from it.

Abstract: A pressureless sintering method is disclosed for use in the production of whisker-toughened ceramic composites wherein the sintered density of composites containing up to about 20 vol. % SiC whiskers is improved by reducing the average aspect ratio of the whiskers to from about 10 to about 20. Sintering aids further improve the density, permitting the production of composites containing 20 vol. % SiC with sintered densities of 94% or better of theoretical density by a pressureless sintering method.

Abstract: A ceramic composite is disclosed which may be used as lightweight armor or for other impact or wear resisting purposes. The ceramic composite may comprise distinct phases of AlN and SiC; may be a solid solution of SiC; or may contain AlN or SiC, or both AlN and SiC as residual phase(s) in a solid solution matrix of SiC and AlN.

Abstract: A composite substrate is provided, which comprises a cordierite-anorthite-boron base composite material and has a microstructure with anorthite included in the cordierite phase. This substrate can be used in the form of a circuit substrate, because it has high-enough mechanical strength, a coefficient of thermal expansion close to that of silicon and a decreased dielectric constant and, moreover, can be sintered at a low temperature.

Abstract: A coating composition for use with ceramic composites to reduce gas permeability of the composites as well as provide an adhesive force to the composites. The coating composition comprises an aqueous dispersion of an aluminum phosphate precursor, silicon carbide, and aluminoborosilicate.

Abstract: A vapor-phase method for treating a beta-spodumene ceramic article to achieve a substitution of exchangeable hydrogen ions for the lithium present in the beta-spodumene crystals, wherein a barrier between the ceramic article and the source of exchangeable hydrogen ions is maintained in order to prevent lithium contamination of the hydrogen ion source and to generate highly recoverable lithium salts, is provided.

Abstract: Described are sintered silicon nitride bodies useful as materials for parts required to have strength, especially excellent impact strength for items such as automobile parts and machine parts. The sintered Si.sub.3 N.sub.4 bodies contain 80-98 wt. % of silicon nitride and have a porosity not higher than 3% and an shock compressive elasticity limit of at least 15 GPa.

Abstract: An aluminum titanate ceramic has as main crystalline phases, a crystalline phase of aluminum titanate and a solid solution thereof, a crystalline phase of mullite and a crystalline phase of rare earth titanate represented by RE.sub.2 Ti.sub.2 O.sub.7 (RE represents Y, Yb, Er, Dy, Ho, Tm or Lu). The aluminum titanate ceramic is superior in casting property and has high heat cycle durability.

Abstract: A plastically deformable mixture and method for making a body from the mixture are disclosed. The mixture is composed of powder materials, which when fired form as predominant phases: ceramic, glass-ceramic, glass, and combinations thereof, 0 to an effective amount of burnout agent, water, organic binder which can be cellulose ether, cellulose ether derivatives or combinations thereof, and hydrophilic and hydrophobic additives, to increase the wettability and/or lubricity of the mixture. One advantageous composition for ram extrusion is composed of ceramic-forming powders, water, and in percent by weight based on the powders, about 2% to 8% organic binder which can be methylcellulose, methylcellulose derivatives, and combinations thereof, about 0.3% to 1.0% sodium stearate, and about 0.5% to 2.0% oleic acid.

Abstract: Self-supporting ceramic bodies comprising a polycrystalline material comprising the oxidation reaction product of a parent metal and having therein one or more channels which inversely replicate the geometry of the configured fugitive metal are formed. These self-supporting bodies may be utilized as articles for regulating and facilitating the passage of a fluid therethrough.

Abstract: A vitreous silica-based plastic refractory comprising at least 50 wt. % vitreous silica having a purity of at least 99% silica, a refractory plasticizer, and a bonding system containing an alpha alumina-containing alumina capable of reacting with phosphoric acid to form an aluminum phosphate bond and phosphoric acid.

Abstract: A process is disclosed for the production of high purity mullites. The process involves reacting a mixture of aluminum alkoxide and silicon alkoxide with an atomic ratio (weight) of Al/Si in the range of 2-7 in an aromatic hydrocarbon solvent at a temperature of 200.degree.-350.degree. C. and calcining the resulting reaction product at a temperature above 900.degree. C. The mullite product obtained finds wide application as a high temperature service structural material such as for automotive engines and turbines as well as a support for combustion catalyst.

Abstract: Mixes for forming high alumina refractory shapes with high resistance to aluminum penetration comprising at least about 60% by weight aluminum oxide, about 1 to 5% by weight boron phosphate, and about 5 to 15% by weight silicon carbide. A phosphorous-containing binder is added and the mix can be formed into brick which when cured or burned to a temperature below the oxidation temperature of silicon carbide can be used to minimize aluminum penetration and dross when the brick are employed in a metallurgical vessel in contact with molten aluminum.

Abstract: Ceramic products consisting principally of cordierite and a method for making them are provided, the method employing batches comprising a mineral component and a chemical component, the mineral component comprising clay and talc and the chemical component consisting essentially of a combination of the powdered oxides, hydroxides, or hydrous oxides of magnesium, aluminum and silicon. Ceramics made by extrusion and firing of the batches can exhibit low porosity, high strength and low thermal expansion coefficients.

Abstract: A process for producing mixed oxides containing an alumina species in which a mixture of a hydrated alumina having a specified surface area (average crystal size), a fluid medium and a compound having the formula M.sub.x A.sub.y wherein M is selected from the group consisting of metals, silicon, boron, arsenic and tellurium, A is selected from the group consisting of oxygen and anions, x is from 1 to 4 and y has a value satisfying said formula depending on the valence of M, is formed into a uniform sol, the sol is recovered from the liquid medium and dehydrated, and the dehydrated product is de-agglomerated to produce a mixed oxide having an average particle size of about 1 micron or less.

Abstract: A method of making a consolidated, reinforced composite member from a matrix mixture including a consolidation shrinkable discontinuous ceramic material, for example ceramic particles, and a selected amount of a particulate inorganic filler which will exhibit net expansion relative to the discontinuous material, the mixture being interspersed about reinforcing fibers. Subsequent consolidation of a preform of such materials can be conducted substantially at ambient pressure, without application of additional pressure, to provide an improved reinforced composite article.

Abstract: Disclosed is an alumina-silica resin additive consisting of amorphous alumina-silica particles in which a definite cubic or spherical shape is retained in primary particles and the particle sizes of both the primary particles and the secondary particles are controlled to very small values. This additive is excellent in dispersibility in a resin, non-blowing property, slip characteristic and anti-blocking property. A product obtained by surface-treating the amorphous alumina-silica particles with a certain amount of an organic lubricant is very valuable as a filler.

Abstract: The inorganic foam body consists of an at least partially open-cell foam formed by thermally foaming and hardening a mixture comprising an alkali water glass and a filler from the group of aluminum oxide, silicon dioxide, aluminous cement, crushed rocks, graphite or mixtures thereof. It is produced by heating a mixture comprising an alkali water glass and a filler from the group of aluminum oxide, silicon dioxide, aluminous cement, crushed rocks, graphite with a blowing agent, and preferably azodicarbonamide, at temperatures of at least 180.degree. C., and preferably of from 200.degree. C. to 300.degree. C. The foam body has a bulk density within the range of from 50 to 500 kg/m.sup.3, and preferably of from 50 to 400 kg/m.sup.3.

Abstract: A fiber-reinforced ceramic composite material reinforced by particle dispersion with improved fracture toughness comprised of a mullite matrix, and fibers and same or different kind of ceramic fine particles both dispersed within the mullite matrix is produced by a method comprising: dispersing mullite particles forming a matrix in a solution dissolving an organometallic macromolecular substance to prepare an impregnating solution, continuously passing fibers through said impregnating solution to uniformly impregnate the fibers with said impregnating solution, laminating said fibers to provide a laminated body, converting the organometallic macromolecular substance within said laminated body into a nonmeltable state, and performing sintering (or press sintering) of said laminated body in an inert gas and/or nitrogen gas. By press sintering K.sub.Ic of 10 MN/m.sup.3/2 or more is achieved.

Abstract: A mullite ceramic composition comprises mullite powder as a raw material; at least one of a rare earth element compound and an alkaline earth element compound; and at least one of a Group 6B vanadium compound, niobium compound and a tantalum compound, and the mixture is fired.

Abstract: This invention relates to a sintered mullite-aluminum titanate article formed by doping the mullite with 1-5% titania and/or titania precursors, and 1-5% hematite and/or hematite precursors, pre-calcining the mullite and mixing with calcined aluminum titanate to form a mullite-aluminum titanate composition which may be formed into a high temperature stabilized ceramic article such as a honeycomb.

Abstract: Needlelike single crystal particles of .alpha.- alumina, .theta.-alumina, mullite, sillimanite, etc. are produced by adding a silicon-containing substance to needlelike alumina precursor particles and heating the resultant product of addition.

Abstract: An aluminum oxide-based sintered object having excellent abrasion resistance includes .alpha.-aluminum oxide, a silicon compound and a tungsten compound, wherein the silicon compound and the tungsten compound are present in amounts based on starting amounts of SiC and W metal of from 5 to 40 mole % and from 0.5 to 25 mole %, respectively, based on the sintered object overall, with a W/SiC molar ratio of 4 or less, and in which particles of at least one of tungsten carbide and tungsten silicide having an average particle diameter of 0.5 .mu.m or less are dispersed as a crystalline phase.

Abstract: The occurrence of efflorescence has been reduced or eliminated in ceramic articles formed from a novel vitreously bonded cement-containing composition. The articles also exhibit improved strength, reduced firing shrinkage and increased frost resistance. The articles are produced by combining hydraulic cement containing calcium silicate and/or calcium aluminate components, vitrifiable inorganic powders forming molten liquid-flowing substances, and reactive or sinterable mineral powders selected from the group consisting of magnesium silicates, aluminum silicates and mixtures thereof; combining the ingredients with water to form a mixture; molding the mixture into an article; hardening the article by hydration; and firing the molded article to a maximum temperature of between about 1000.degree. C. to 1400.degree. C.

Abstract: A refractory composition, particularly for application as a dry vibratable refractory for forming the wearable, disposable monolithic lining coating the permanent lining of a tundish or ladle used in molten metal casting processes is disclosed. The composition contains a refractory aggregate, a first bonding agent actuatable at temperatures in the range of from about 300.degree. F. to about 1000.degree. F. to cause the formation of interparticle bonds between aggregate particles, at least one second bonding agent actuatable at temperatures in the range of from about 1000.degree. F. to about 2500.degree. F. to cause further formation of interparticle bonds between aggregate particles, and, optionally, clay. The use of both first and second bonding agents enables installation of the refractory in hot practice, in which vessel preheat temperatures of up to about 2500.degree. F. are utilized.

Abstract: Porous sintered ceramic material having bulk analytical composition, by weight, of 74-79% alumina and the balance being silica optionally with other oxide and/or impurities naturally occurring from the batch materials, and having a phase composition, by weight, of 50-75% mullite, 23-45% corundum, 0-6% cristobalite and the balance being substantially 2-10% amorphous alumina-silica based phase. Honeycomb structure, molten metal filter and catalytic converter made from the material.

Abstract: A proteinaceous gelatin binder is used to make aqueous green ceramic compositions suitable for forming green ceramic tape by tape casting. Any known ceramic may be used. The tapes may be fired individual or as a laminate to produce sintered ceramic articles.

Abstract: A method of producing a self-supporting ceramic composite body having therein at least one cavity which inversely replicates the geometry of a positive mold of parent metal. The method includes embedding the mold of parent metal within a conformable bed of filler to provide therein a cavity shaped and filled by the mold. The assembly is heated to melt the parent metal mold, e.g., an aluminum parent metal mold, and contacted with an oxidant to oxidize the molten parent metal to form a polycrystalline material which grows through the surrounding bed of filler, the molten metal being drawn through the growing polycrystalline material to be oxidized at the interface between the oxidant and previously formed oxidation reaction product whereby the cavity formerly filled by the mold of parent metal is eventually evacuated of the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold.

Abstract: Green bodies suitable for use in manufacturing ceramic articles are provided. The bodies comprise a coherent mass of particles of aluminium oxide free of organic binder and having a fracture stress measured by a biaxial disc flexure test of at least 10 MPa. The particles of aluminium oxide are coated with at least one inorganic oxide or hydrous oxide.The green body can be shaped by drilling, sawing etc. to a desired shape approximating to that of the ceramic article which it is used to produce. Generally such shaping is considerably easier than shaping the finished ceramic article.

Abstract: A granular abrasive material is produced from a dispersion consisting of raw materials containing alumina, compounds containing silica and other additives. The dispersion is ground to a sinterable slip with a grain size of less than 1 micrometer. The slip is dried and may be pressed before being subjected to a multi-stage heating process to produce sintered corundum crystals.

Abstract: A refractory mix for forming high strength, low thermal conductivity refractory shapes comprising from about 40 to 75% by weight of at least one dense refractory aggregate, about 10 to 30% by weight of a bonding agent, and about 5 to 25% by weight of hollow ceramic microspheres having a diameter of about 1 to 350 microns.

Abstract: A building product comprises slate particles e.g. flakes, slivers, chips, fragments, and/or powdered dust particles bonded together by a fused glassy binder.

Abstract: The heat resistant expansion member used as the holding member of the ceramic honeycomb monolithic catalyst in an automobile comprises 20 to 40 wt. % of sepiolite, 30 to 54 wt. % of particulate vermiculite, 20 to 40 wt. % of ceramic fibers, and 5 to 20 wt. % of organic bonding material, or 20 to 40 wt. % of sepiolite, 30 to 54 wt. % of treated vermiculite, 20 to 40 wt. % of ceramic fibers, 5 to 20 wt. % of organic bonding material, and 1 to 10 wt. % of E-glass with fiber diameter of 1 .mu.m or less, so that a large holding force is maintained whether in a low temperature region or in a high temperature region.

Abstract: A ceramic whisker body is disclosed which is coated with an oxide or non-oxide ceramic coating which is uniform, continuous, non-particulate and when the whisker is incorporated into a whisker reinforced ceramic matrix composite, the ceramic coating inhibits fusing between the whisker and the matrix, yielding a strengthened ceramic composite. An efficient method for applying both oxide and non-oxide ceramic coatings onto ceramic whiskers is also disclosed.

Abstract: A composition of matter which is a powder mixture for use in a process of forming a porous refractory mass on a surface, the composition including refractory particles, fuel particles which are capable or reacting exothermically with an oxidizing gas to forming at least one refractory oxide and which are present in a quantity effective to release, on projection together with the oxidizing gas, sufficient heat to melt at least the surfaces of the refractory particles so that the refractory particles and at least some of the at least one refractory oxide bond together; and particles of porosity-inducing material comprised of at least one of hollow and porous particles which become incorporated in the refractory mass formed on projection and which have at least one of a composition and a particle size selected so that incorporation of the porosity-inducing material in the powder mixture results in the formation of porosity within the refractory mass formed on projection.

Abstract: This invention relates to a method for producing a self-supporting ceramic structure comprising an oxidation reaction product of a parent metal and a vapor-phase oxidant characterized by an altered microstructure attributable to the addition of one or more process modifiers relative to substantially the same oxidation reaction product produced without a process modifier.

Abstract: A lightweight oil and gas well proppant made by simultaneously mixing and compacting a mixture of kaolin clay which has been calcined at a temperature low enough to prevent the formation of mullite and crystobalites to an LOI of 12 or less when tested at 1400.degree. C., and amorphous to microcrystalline silica both of which have been milled to an average agglomerated particle size of 7 microns or less to form green pellets, and then drying, screening and sintering the pellets to form proppant pellets having a specific gravity of 2.7 or less, the proppant having a conductivity of at least 3,000 millidarci-feet as measured by the Stim-Lab Technique after 50 hours at 8,000 psi and 275.degree. F. in the presence of deoxygenated aqueous 2% solution of KCl using sandstone shims.