Abstract: Ceramic precursor materials bound together by a product of a condensation reaction between a first reactant that has at least one reactive hydroxyl moiety, such as a carbohydrate, and a second reactant that has at least one reactive nitrogen-containing moiety, such as melamine, and dried or dried and calcined, form porous aggregates that resist crushing or disintegration during processing through various reactor apparatus.

Abstract: Improved fiber reinforced composites having near zero coefficients of thermal expansion are described. The improved composites include reinforcing fibers and matrix material in which gap structures which exist within the composite are filled with a bonding agent. The reinforcing fibers can be unidirectionally, bidirectionally or multidirectionally oriented within the matrix material and articles fabricated from the improved composite have reduced coefficients of thermal expansion in directions transverse to the orientations of the fibers. This improvement makes these improved composites useful for fabricating high energy laser mirror substrates.

Abstract: A dry vibratable substantially alkali free refractory composition is disclosed for use as a disposable liner wherein the combination of a powdered metal utilized as a high temperature binder and an organic material utilized as a low temperature binder obviates the use of alkali oxides which previously caused degradation of the permanent refractory liner materials upon which the disposable lining was placed. Low density materials such as expanded inorganic materials can be added to the disclosed compositions to decrease the density. The invention also relates to a method of providing a disposable lining in a vessel having a permanent refractory lining, and to the resulting vessel thereof.

Abstract: Disclosed is a process for preparing a solid, light weight mineral foam which is stable during its preparation and during its subsequent curing and drying and which, thanks to its composition and the way it is prepared, can be injected in situ, substantially like a urethane foam. This foam has a density ranging from 10 to 65 lb/pi.sup.3 and is made of 1 part by weight of a solution of phosphoric acid of given concentration in which is dissolved polyvinyl alcohol in such an amount as to make the solution viscous; from 0.03 to 6 parts by weight of wollastonite containing from 0.5 to 4% by weight of a carbonate salt; and from 0.2 to 10 parts by weight of water. The amount of water depends on the concentration of the solution of phosphoric acid and of the required density of the foam, it being understood that the more concentrated is the solution of phosphoric acid and/or the lower is the required density, the higher is the amount of water.

Abstract: The preparation of porous ceramic bodies by sintering certain curable organopolysiloxanes filled with silicon carbide powders. This process is advantageous in that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering.

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: Ceramic bodies having conically shaped pores are produced by electrophoretic deposition from aqueous ceramic particle suspensions. The dense ceramic bodies may be fabricated in the form of tubes having the pores radiating inward or outward. Alternatively, other shapes may be fabricated. The bodies are useful as filters, burner elements, catalysts supports, etc.

Abstract: Ceramic beads having a bimodal pore distribution are prepared by a process involving a) formation of a ceramic particle slurry, b) adding a foamable prepolymer to the slurry to form a mixture, c) dispersing the mixture as beads in a second liquid, d) polymerizing and foaming the prepolymer, e) recovering the beads and firing them to remove the polymer and bond the ceramic particles. The beads can optionally be joined by sintering. Beads with a monodal pore distribution can be made by using a nonfoaming prepolymer.

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: Ceramic foams in which the open cells are connected by a three-dimensional, substantially continuous ceramic matrix formed of interconnected hollow ligaments, are made from an open-cell, reticulated precursor metal, i.e. a metal foam. The precursor metal first is treated so as to allow a support coating to form thereon, and thereafter the coated precursor is heated above the melting point of the metal in the presence of an oxidant to form an oxidation reaction product.

Abstract: A refractory ceramic material, including a porous base refractory material and a zirconia protective layer covering walls of pores of the porous base refractory material, wherein the refractory ceramic material has a porosity of not less than 80%, and the zirconia protective layer has a thickness not more than about 1 nanometer.

Abstract: The present invention provides an as-fired, high alumina, low silica, corrosion resistant, refractory product and a method for making said product where the product includes from about 50 wt. % to about 80 wt. % of a bubble alumina, from about 10 wt. % to about 30 wt. % of a fine calcined alumina and from about 5 wt. % to about 20 wt. % of a fine hydrated alumina. The product is characterized by having an alumina content of at least 98 wt. % alumina, a silica content of less than 1 wt. %, a density of from about 80 to about 95 pounds per cubic feet, a porosity of from about 55% to about 65%, a room temperature modulus of rupture of at least 200 psig and a cold crushing strength of from at least 200 psi.

Abstract: A gas injection stone is manufactured by embedding in a refractory compound a plurality of adjacent and abutting nets. Thereby, when the refractory compound is solidified and when the nets subsequently are removed by burning or melting, the result will be the formation within the stone of plural interconnected layers of interlinked gas channels.

Abstract: An inorganic particulate material comprising fine balls approximately uniform in size and 0.1 to 50 .mu.m in mean particle size and prepared by admixing an aqueous solution of at least one compound (i) selected from among halides of alkaline earth metals, inorganic acids, organic acids, ammonium salts or inorganic acids, ammonium salts of organic acids and carbonates of alkali metals with an aqueous solution of at least one inorganic compound (ii) selected from among silicates, carbonates, phosphates or sulfates of alkali metals, halides of alkaline earth metals, and sulfates, hydrochlorides or nitrates of copper family elements o iron family elements before or after admixing an organic solvent (iii) with said aqueous solution of at least one inorganic compound (ii) to form a W/O emulsion, said compound (i) being capable of forming a water-insoluble precipitate when subjected to an aqueous solution reaction with said inorganic compound (ii).

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 process for producing composite materials with a metal matrix and with a content of powder reinforcer agent lower than is minimum theoretical compaction value, with said process being based on an infiltration technique, is disclosed, which essentially consists in charging the reinforcer material to a casting mould, and then infiltrating into the same mould the metal matrix in the molten state, with said metal matrix being let cool until it solidifies, and characterized in that the reinforcer agent, consisting of non-metal powders, is blended, before being charged to said casting mould, with a diluting agent having a different compaction degree, constituted by metal fibres and/or ceramic fibres and/or ceramic whiskers and/or metal powders of the same composition as of the matrix.

Abstract: A method for forming a porous carbonaceous preform comprises, forming a mixture comprised of up to about 50 volume percent of furfuryl alcohol or tetrahydrofurfuryl alcohol, about 1 to 10 volume percent of a nonionic polyethylene oxide polymer ranging in molecular weight from about 100,000 to 5,000,000, about 30 to 80 volume percent of a carbonaceous material, and the balance water. The mixture is cast to form a body, and heated to decompose the polymer and form the porous preform. A molding composition for carbonaceous material comprises, up to about 50 volume percent of furfuryl alcohol or tetrahydrofurfuryl alcohol, about 1 to 10 volume percent of a nonionic polyethylene oxide polymer ranging in molecular weight from about 100,000 to 5,000,000, about 30 to 80 volume percent of the carbonaceous material, and the balance water.

Abstract: This invention relates to a foamable silicate composition comprising (a) one or more alkali metal silicates, (b) a blowing agent, (c) a hardener which can be an acetate or a formate ester of a di-polyhydric alcohol or a polyoxyalkylene glycol and (d) a surfactant having a hydrophilic-lypophilic balance of at least 8. The formulations are readily produced by mixing the components, are pourable, pumpable and sprayable, and give rise to foams of excellent compressive strength and thermal insulation properties under ambient conditions.

Abstract: A process for preparing uniform, agglomerate free, submicron/nanosize ceramic powders from a polymeric foam comprising metal cations homogeneously incorporated within a foam cell structure of the polymeric foam. The polymeric foam is heated to remove any solvent, and calcined at a temperature of about 400.degree. C. to about 1200.degree. C. for about 1/2 to about 8 hours to produce the desired ceramic or metal powder.

Abstract: A method for forming a porous carbonaceous preform includes forming a mixture comprised of up to about 50 volume percent of furfuryl alcohol or tetrahydrofurfuryl alcohol, about 1 to 10 volume percent of a nonionic polyethylene oxide polymer ranging in molecular weight from about 100,000 to 5,000,000, about 30 to 80 volume percent of a carbonaceous material, and the balance water. The mixture is cast to form a body, and heated to decompose the polymer and form the porous preform. A molding composition for carbonaceous material includes, up to about 50 volume percent of furfuryl alcohol or tetrahydrofurfuryl alcohol, about 1 to 10 volume percent of a nonionic polyethylene oxide polymer ranging in molecular weight from about 100,000 to 5,000,000, about 30 to 80 volume percent of the carbonaceous material, and the balance water.

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: There is provided a thermal shock-resistant silicon nitride sintered material including silicon nitride and rare earth element compounds, which material contains at least 10 pore groups per mm.sup.2, each pore group consisting of pores of 10 or less in diameter and which material has a thermal shock resistance .DELTA.Tc (.degree.C.) of 1,000.degree. C. or more. The thermal shock-resistant silicon nitride sintered material can be produced by mixing and shaping starting materials consisting of silicon nitride powders of rare earth element oxides and carbide powder, and then firing the shaped material in a nitrogen atmosphere to decompose the carbide powders.

Abstract: A method of making metal oxide ceramic material is disclosed by which the porosity of the resulting material can be selectively controlled by manipulating the sol used to make the material. The method can be used to make a variety of metal oxide ceramic bodies, including membranes, but also pellets, plugs or other bodies. It has also been found that viscous sol materials can readily be shaped by extrusion into shapes typical of catalytic or adsorbent bodies used in industry, to facilitate the application of such materials for catalytic and adsorbent applications.

Abstract: The invention relates to a process and an apparatus for converting metal nitrate or mixed metal nitrate solutions into the corresponding metal oxides in a microwave field. The invention consists in heating, while the feed stream is being metered in, in such a manner that the solvent always evaporates within seconds and the decomposition product is obtained as a porous, sponge-like, purely oxidic material, which can be ground easily to give a powder having particle sizes of 0.5 to about 10 .mu.m. The controlled metering in of the nitrate solution simultaneously makes it possible to control the reaction temperature below the sintering temperature of the powder. The reaction of the nitrate starting solution can take place continuously/batchwise in a reaction flask or continuously in a rotating reaction pipe, which is preferably charged with grinding balls, which possibly exert a reaction-activating effect similar to that exerted very particularly by the metal oxide sponge formed during the reaction.

Abstract: A porous refractory carbide with a large specific surface area is disclosed. The refractory carbide has a skeleton of metallic or metalloid refractory carbide and has a bimodal open porosity with a group of pores of 1 to 100 microns and a group of pores smaller than 0.1 micron.

Abstract: A rigid, monolithic, porous gas diffusion element which is formed of a body of solid particles and which is comprised of a partially coated, permeable ceramic substrate is disclosed. The substrate consists essentially of a porous first ceramic material, has an apparent porosity of from about 35 to about 50 percent, and has a minimum active pore size of from about 40 to about 120 microns; and it is partially coated with a coating which consists essentially of a second ceramic material, has an apparent porosity of from about 35 to about 55 percent, and has a minimum active pore size of from about 10 to about 40 microns. The minimum active pore size of the substrate is from about 2 to about 5 times as great as the minimum active pore size of the coating.

Abstract: A process for producing a sintered apatite article having a porous surface by contacting a dense sintered apatite article with an acidic buffer solution, provided that the acidic buffer solution does not contain phosphoric acid.

Abstract: Methods for preparing a green sheet and a glass ceramic substrate are herein disclosed.

Abstract: A ceramic foam filter, particularly for filtering molten iron, is formed from a composition comprising silicon carbide, alumina, silica derived from colloidal silica sol and alumino-silicate fibres, which has been fired at such a temperature that the filter has a ceramic matrix in which the alumino-silicate fibres are substantially dissolved. The filter is fired at a minimum of 1150.degree. C. and preferably within the range from 1200.degree. to 1300.degree. C. Preferably the filter is formed from an aqueous slurry having a solids content comprising by weight 20-50% silicon alumina, 20-50% alumina, 1.5-5.0% silica derived from colloidal silica sol and 1-3% alumino-silicate fibres.

Abstract: Ceramic foams in which the open cells are connected by a three-dimensional, substantially continuous ceramic matrix formed of interconnected hollow ligaments, are made from an open-cell, reticulated precursor metal, i.e. a metal foam. The precursor metal first is treated so as to allow a support coating to form thereon, and thereafter the coated precursor is heated above the melting point of the metal in the presence of an oxidant to form an oxidation reaction product.

Abstract: A porous ceramic body of high structural strength and integrity is disclosed, along with the method of fabricating such, whereby a curable resin and a sinterable ceramic are mixed and then admixed to removable pore formers, then consolidated into a green body, the pore formers removed, and sintered into the porous ceramic body.

Abstract: A porous ceramic sinter and a process for producing the same are disclosed, which sinter has macropores with a pore size of from 20 to 2,000 .mu.m and three-dimensionally communicating pores that are made of interstices between secondary particles.

Abstract: A porous filter for metal hot melt comprises ceramic aggregate particles bound by an inorganic binder. The aggregate particles contain not less than 50 wt % of particles with a shape factor in the range of 100 to 130 and the binder has needle-shaped crystals deposited on the surface thereof. By employing this filter, debris catching ability and initial impregnation of metal hot melt are highly improved.

Abstract: The method of making a foamed, low density shaped refractory product consisting of TiB.sub.2 and Al.sub.2 O.sub.3 which comprises the steps of foaming an exothermic reaction mixture consisting of TiO.sub.2, B.sub.2 O.sub.3 and Al, loading the reaction mixture into a self sustaining shape, locally igniting the shaped reaction mixture in air at ambient conditions and recovering the foamed, low density, shaped refractory product.

Abstract: High-strength, non-agglomerated uniform porous microspheres of silica produced by spray drying a mixture comprising a colloidal silica sol and an additive selected from ammonium citrate or urea; an attrition resistant catalytic composite consisting essentially of metal crystallites such as palladium, platinum-palladium on said silica microsphere and method for preparing the same; and an improved process for making hydrogen peroxide from the direct combination of hydrogen and oxygen in the presence of said attrition resistant catalytic composite.

Abstract: The invention provides a process for modifying a ceramic and/or metallic porous material having open cells necessary for the material to serve the function of gas diffusing materials, filters or the like. The porous material is subjected to hot isostatic pressing at a temperature at which the base portion of the porous material softens or melts to compact or homogenize the base portion.

Abstract: There is provided a thermal shock-resistant silicon nitride sintered material consisting substantially of silicon nitride and rare earth element compounds, which material contains at least 10 pore groups per mm.sup.2, each pore group consisting of pores of 10 .mu.m or less and which material has a thermal shock resistance .DELTA.Tc (.degree.C.) of 1,000 .degree. C. or more. The thermal shock-resistant silicon nitride sintered material can be produced by mixing and shaping starting materials consisting of a silicon nitride powders of rare earth element oxides and carbide power, and then firing the shaped material in a nitrogen atmosphere to decompose the carbide powders.

Abstract: Machinable ceramic composites having a low dielectric constant. The composite comprises ceramic bubbles uniformly distributed throughout a ceramic matrix. These composites can be used as ceramic substrates and housings in electronic packaging, and as windows transparent to microwave and millimeter wave radiation.

Abstract: A ceramic material made of a skeleton reaction-bonded silicon powder is distinguished by an open-cell pore structure produced by using a matrix of an appropriately shaped polyurethane foam structure. For the preparation, a foam matrix is coated with a suspension of silicon powder, synthetic resin and solvent and is subjected to a heat treatment, during which the foam matrix is expelled and the silicon is stabilized. The thermally and chemically stable product can be used, for example, as a filter medium for metal melts, as a catalyst carrier, or as a boundary medium between the flame zone and unignited combustible mixtures in burners.

Abstract: Forming a filter for a gas lighter using a sintered porous ceramic, and adjusting the flow rate of gas through gas passages formed by interparticle pores of ceramic. There will be no change in the flame length even in the use of the gas lighter over a long period, thereby enhancing the safety of the gas lighter.

Abstract: Discrete, free-flowing, ceramic microbubbles consist essentially of at least one of a non-oxide component and an oxide component having diameters in the range of 1 to 300 micrometers and each having a wall thickness of less than 10 percent of the diameter of the bubble. In the process of the invention, a sol precursor and a suitable liquid, referred to as a bloating agent, when added to a bubble promoting medium under proper conditions, provide green gelled microbubbles which after firing are ceramic microbubbles having wall thicknesses less than 10 percent of the diameter of the bubbles. The microbubbles are non-vitreous, sol-gel derived, fine microstructured, uniform, hollow, smooth, and are either essentially all oxide or non-oxide or combinations of both.

Abstract: Sol-gel processing techniques are used to produce alkali-free bioactive glass compositions based on SiO.sub.2, CaO and P.sub.2 O.sub.5. By varying the SiO.sub.2 content, a range of hydroxyapatite production rates can be obtained; conversely, varying the time of exposure to actual or simulated in vivo solutions permits use of a range of allowable proportions of SiO.sub.2. The sol-gel derived compositions can be chosen to achieve target values for thermal expansion coefficient, elastic modulus and volume electrical resistivity.

Abstract: A thermal barrier coating for substrates comprising zirconia partially stabilized by yttria and having a density greater than 88% of the theoretical density with a plurality of vertical macrocracks homogeneously dispersed throughout the coating to improve its thermal fatigue resistance. The invention also discloses a process for producing the thermal barrier coating.

Abstract: Lightweight, low density magnesia-based tundish refractory compositions containing from 0.01 to 2.00 weight percent styrofoam beads and up to 5.0 weight percent paper fiber are disclosed. The compositions have excellent rapid heating, thermal insulative, vertical adhesion and deskullability properties. The compositions are useful as a lining applied over the permanent lining of a tundish, such as is used in continuous molten metal casting processes.

Abstract: A ceramic material for use in insert-casting, which contains not less than 65% by volume of aluminum titanate as a crystalline phase. The average particle diameter of crystals of the aluminum titanate is not less than 10 .mu.m, and not more than 20% by volume of a glass phase containing a rare earth element in an amount of 0.5 to 16% by weight when calculated in the form of an oxide is contained. Young's modulus is 50 to 2,000 kgf/mm.sup.2. A process for producing the same is also disclosed, which includes the steps of preparing a powder by mixing a material, as an Al.sub.2 O.sub.3 source material, containing not more than 96% by weight of Al.sub.2 O.sub.3 and having an average particle size of not less than 3 .mu.m, a material having an average particle diameter of not more than 3 .mu.m as a TiO.sub.2 source material, and a given rare earth element in an amount of 1.8% by weight when calculated in the form of an oxide, shaping the powder, and drying and firing the shaped body.

Abstract: A process for forming a porous refractory mass on a surface is characterized in that an oxidizing gas is projected against that surface together with a powder mixture which comprises: refractory particles; particles of fuel which reacts exothermically with the oxidizing gas to form refractory oxide and release sufficient heat to melt at least the surfaces of the refractory particles so that they bond together to form the refractory mass; and particles of material whose composition and/or size is selected so that the incorporation of such material in the projected mixture results in the formation of porosity within the refractory mass formed. The porosity-inducing material may be such as to burn to evolve gaseous combustion products, it may decompose to gaseous decomposition products, or it may itself be porous or hollow.

Abstract: Ceramic foams in which the open cells are connected by a three-dimensional, substantially continuous ceramic matrix formed of interconnected hollow ligaments, are made from an open-cell, reticulated precursor metal, i.e., a metal foam. The precursor metal first is treated so as to allow a support coating to form thereon, and thereafter the coated precursor is heated above the melting point of the metal in the presence of an oxidant to form an oxidation reaction product.

Abstract: The present invention relates to a ceramic foam material, preferably a ceramic foam filter, prepared by providing an open cell flexible foam having a plurality of interconnected voids surrounded by a web of the flexible foam, applying an adhesion promoting material to at least one surface of the flexible foam, impregnating the flexible foam after applying the adhesion promoting material with a ceramic slurry, drying and heating the impregnated material to remove the organic component therefrom, and firing at an elevated temperature to form the filter. In a preferred embodiment, a flocked coating is formed on at least on surface of the flexible foam prior to impregnation. The flocked coating may be formed either by first applying a solution containing an adhesive to the surface(s) and thereafter applying fibers to the surface or by applying a solution containing the adhesive and the fibers.

Abstract: A porous ceramics material produced by the process comprising the steps of (i) mixing two or more ceramics in such a manner that at least one of the ceramics is different in sinterability from the others and is mixed in an amount of from 1 to 99 wt % based on the total amount of the ceramics; and (ii) sintering thus obtained mixture; a packing for chromatography comprising the porous ceramics material; and a process for producing the porous ceramics material.

Abstract: Disclosed is a low density foam having a porosity of from 0 to 98% and a density less than about 0.67 gm/cc, prepared by heating a mixture of powered lithium hydride and beryllium hydride in an inert atmosphere at a temperature ranging from about 455 to about 490 K for a period of time sufficient to cause foaming of said mixture, and cooling the foam thus produced.Also disclosed is the process of making the foam.