Abstract: Si.sub.3 N.sub.4 -based sintered compositions containing MgO and optionally other sintering additives, which after sintering, has a flexural strength level at room temperatures of .gtoreq.800 MPa, measured by the four-point bending method, and a Weibull modulus of >15, is produced by mixing MgO, any additional sintering additives and Si.sub.3 N.sub.4 powder to form a mixture, calcining the mixture in an oxygen-free atmosphere to obtain a pre-synthesis mixture, and adding the pre-synthesis mixture to uncalcined Si.sub.3 N.sub.4 powder which is then sintered.

Abstract: A refractory mix for forming a fused silica based refractory shape consisting essentially of a high purity fused silica and a binder system consisting essentially of a high purity colloidal silica solution and a high purity ammonium lignosulfonate. The invention also comprises fused silica based refractory shapes formed from such mix by pressing and firing.

Abstract: A composite silicon nitride sintered body formed of silicon nitride as a matrix and silicon carbide having particle sizes of 5 to 500 nm as a phase dispersed in the sintered body, wherein the total amount of dispersed silicon carbide is 1 to 40% by volume based on the sintered body, the proportion by volume of the silicon carbide dispersed in the silicon nitride particles is 5 to 99% based on the total amount dispersed, the remainder being present only in the grain boundary of the silicon nitride, and a process for producing a silicon nitride composite sintered body which includes the steps of adding a sintering aid to amorphous composite powders as starting materials consisting of silicon, nitrogen and carbon to form a green compact; firing the green compact in a nitrogen atmosphere at 1350.degree. to 1650.degree. C. as the primary sintering; firing the same at 1600.degree. to 1900.degree. C. as the secondary sintering; and firing the same at 1800.degree. to 2200.degree. C.

Abstract: High-packing silicon nitride powder is prepared by reacting metallic silicon powder having a mean particle size of 1 to 10 .mu.m and a purity of at least 99% directly with nitrogen for forming silicon nitride powder, milling the silicon nitride powder in a dry attritor until the tap density exceeds 0.9 g/cm.sup.3 and the content of particles having an aspect ratio of up to 3 exceeds 95% by weight, and further milling the silicon nitride powder in a wet attritor for finely dividing coarse particles having a particle size of at least 2 .mu.m. The silicon nitride powder has a tap density of at least 0.9 g/cm.sup.3 and a mean particle size of 0.4 to 0.6 .mu.m and contains at least 95% by weight of particles having an aspect ratio of up to 3 and up to 5% by weight of coarse particles having a particle size of at least 2 .mu.m. The powder is moldable into a high density compact, from which a sintered part having improved dimensional precision and strength is obtained.

Abstract: The materials for living hard tissue replacements of the present invention comprise a ceramic material which contain Cao and SiO.sub.2 as essential components, and MgO as an optional components, are substantially free from calcium phosphate and are capable of forming a compound based on calcium phosphate by contact with an aqueous solution containing phosphorus, and show high biological affinity.

Abstract: A quartz glass substrate for polysilicon thin film transistor liquid crystal display, in which a halogen content is not more than 10 ppm; an OH content is not more than 100 ppm; a total content of a heavy metal element and an alkali metal element is not more than 1 ppm; and an annealing point is not less than 1,150.degree. C.

Abstract: A vestibule block or interior furnace wall utilized in a diffusion furnace for manufacturing semi-conductors, integrated circuits and the like, and which is made of refractory or ceramic material, is treated on its surface with a suspension of fine particulate of a glass frit composition comprising an alkali earth metal alumino silicate, and is thereafter heated above the transition temperature of the alkali earth metal alumino silicate. Vestibule blocks and interior surface walls which have been treated in the above-described manner are highly abrasion resistant on their surface, generate virtually no particulate matter under conditions of ordinary use in the semi-conductor manufacturing processes, and generate significantly less particulate matter when tested in an abrasion test against vestibule blocks of the prior art.

Abstract: Quartz glass obtained by flame-hydrolyzing a glass-forming raw material to obtain fine particles of quartz glass, having the fine particles of quartz glass deposited and grown on a substrate to obtain a porous quartz glass product and heating the porous quartz glass product to obtain a transparent quartz glass product, which has an OH content of not more than 10 ppm and a halogen content of at least 400 ppm and which contains hydrogen.

Abstract: Disclosed is a ceramic composite which comprises particles of at least one inorganic compound selected from the group consisting of a carbide, a nitride, an oxide, a boride, a silicide and an oxy-nitride and particles and whiskers of Si.sub.3 N.sub.4, Si.sub.2 N.sub.2 O or SiO.sub.2. This ceramic composite is small in volume change on sintering, and provides heat resistance. In addition, the composite can absorb thermal shock by its voids. It can be used in association with ceramic heaters, current collectors, commutators for starter motors and alternators, and in other areas.

Abstract: A sintered body of silicon nitride base solidly formed of interior and surface portions wherein the rate of decrease of the content Si or Si.sub.3 N.sub.4 and Sialon grains in the surface portion, with respect to that in the interior portion, is not less than 20% by weight or 30-100 vol %, respectively. The grain boundary phase of the surface portion is glassy, or crystallized partly or entirely. Crystallized boundary phase comprises Si.sub.3 N.sub.4 -Y.sub.2 O.sub.3 base compounds Si.sub.3 N.sub.4 -nY.sub.2 O.sub.3 -mX (n=1-5, X=SiO.sub.2, Al.sub.2 O.sub.3, m=0-4) such as mellilite, J phase (mohlerite), K phase (wollastonite), H phase (apatite), or A phase (Si.sub.3 N.sub.4.5Y.sub.2 O.sub.3.Al.sub.2 O.sub.3). Sintering aids of Al.sub.2 O.sub.3, Y.sub.2 O.sub.3, AlN, MgO, CaO, Y.sub.2 O.sub.3 and/or rare earth oxides form boundary phases.

Abstract: A method which enables easy and efficient production of silica brick having small content of residual silica by firing from a siliceous stone material containing silica as the main component, even when the siliceous stone material used is of the type in which transformation of silica is not easy to occur. The method is characterized by adding 0.2 to 5 wt % of Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material to the siliceous stone material. The Na.sub.2 O--CaO--SiO.sub.2 fused and solidified material, together with a binder, is added to pulverized siliceous stone material, and the mixture is then formed followed by a firing at 1350.degree. to 1500.degree. C., so that the Na.sub.2 O-13 CaO--SiO.sub.2 fused and solidified material reacts with silica in the siliceous stone material to promote transformation of the silica into cristobalite and tridymite.

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: There is disclosed a method for making a self-supporting ceramic composite article having a porous core bearing a dense surface layer formed integrally with said core. A preform comprises a filler material and parent metal distributed therethrough, wherein the volume percent of parent metal is sufficient to form a volume of oxidation reaction product exceeding the total volume available within said preform. The parent metal is melted and reacted with an oxidant to form an oxidation reaction product filling the spatial volume and leaving voids. The reaction is continued to further transport molten parent metal through the oxidation reaction product to at least one surface of the preform to form oxidation reaction product on said surface substantially free of voids thereby forming a relatively dense surface layer.

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: Cordierite-forming green substrates having high wet strength are prepared from fine-particle size minerals, including about 5 to 30 weight percent of delaminated kaolin and, preferably, about 15 to 39 weight percent calcined kaolin. The other fine-particle size minerals utilized are preferably talc having a particle diameter of about seven microns or less and alumina having a particle diameter of about one micron or less.

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: Disclosed are an oxide superconductor, and an optimum process for producing the same. The oxide superconductor comprises a base material phase including an oxide superconducting material, the oxide superconducting material including barium (Ba) at least and being free from grain boundaries, and precipitation phases contained in an amount of 1 to 50% by volume in the base material phase and dotted therein in a manner like islands, the precipitation phases being oxides of a metal selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), magnesium (Mg), titanium (Ti), strontium (Sr), tungsten (W), cobalt (Co) and vanadium (V), and being products of decomposition reaction of the base material phase. In the production process, the constituent materials are treated thermally at a partially melting temperature in order to give the above-described novel structure to the oxide superconductor.

Abstract: The present invention relates to a novel method of manufacturing a composite body, such as a ZrB.sub.2 --ZrC--Zr composite body, by utilizing a post-treatment technique which may improve the oxidation resistance of the composite body. Moreover, the invention relates to novel products made according to the process. The novel process modifies at least a portion of a composite body by exposing said body to a source of second metal.

Abstract: This invention relates to an improved pack mixture composition useful for the formation of a SiC pack cementation coating for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: Si from about 15% to about 50% by weight of the total composition; B up to about 25% by weight of the total composition when present; SiO.sub.2 from about 0.01% to about 3% by weight of the total composition; and SiC from about 40% to about 85% by weight of the total composition.The invention also relates to a method for protecting a carbonaceous substrate from degradation at temperatures above about 800.degree. F. comprising: preparing a pack mixture composition of from about 15% to about 50% Si, up to about 25% B, from about 0.01% to about 3% SiO.sub.

Abstract: Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions.

Abstract: The invention relates to ceramic composite articles formed by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix produced as a metal-oxidant reaction product. The bed or preform includes a dross material.

Abstract: The present invention provides a temporary rust resisting coating composition which has excellent rust resistance after heating even at more than 600.degree. C. and which has good weldability. The temporary rust resisting coating composition of the present invention comprises(A) 10 to 25% by weight of a binder having an ignition loss of not more than 33% by weight,(B) 40 to 70% by weight of zinc powder,(C) 5 to 50% by weight of an inorganic oxide pigment which has been heated at not less than 500.degree. C. up to an ignition loss of 3% by weight;the amounts of the components (A), (B) and (C) being based on a dried film.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron donor material and a carbon donor material. The reactive infiltration typically results in a composite comprising a boron-containing compound, a carbon-containing compound and residual metal, if desired. The mass to be infiltrated may contain one or more inert fillers admixed with the boron donor material and carbon donor material. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing a wide ranging varying volume percentage of ceramic, metal, and porosity.

Abstract: The present invention provides a method of annealing optical glass layers, said method comprising the step of heating glass layers having an area greater than 0.01 cm.sup.2 to a temperature of between about 350 deg. C. and 1000 deg. C. in less than 10 minutes. The upper limit of the glass area that can be treated is limited only by the size of the quartz chamber. Current state-of-the-art chambers can accomodate glass areas of about 0.01 cm.sup.2 to about 324 cm.sup.2. According to another aspect of the invention, there is also provided an optical waveguide glass layer, treated according to the method of this invention, disposed on an integrated optical device.

Abstract: Stable, non-gelling and pumpable aqueous suspensions of precipitated silica particulates, well adapted for the coating of paper and cardboard substrates, include an effective stabilizing amount of at least one biogum heteropolysaccharide and at least one quaternary ammonium, sulfonium or phosphonium compound (cationic surfactant).

Abstract: Diamond-containing ceramic composites useful as substrates and the like in the electronics industry as well as for abrasive and cutting applications and methods of making same are disclosed. More specifically, the sol-gel process is used to fabricate the composites by combining water, an organometallic precursor compound, alcohol or similar solvent between the water and the precursor compound, a catalyst, diamond powder and a thickening agent to form a moldable, wet, porous gel which can be dried at a temperature below the boiling point of any of the gel liquids to form a stabilized porous composite. The stabilized porous composite can be densified, by heat, in an essentially oxygen-free atmosphere to form a diamond-containing ceramic composite having low porosity.

Abstract: This invention relates to lead-free and cadmium-free frit compositions for glazes and enamels which consist essentially, expressed in terms of weight percent on the oxide basis, of______________________________________ SiO.sub.2 51-59 CaO 0-7 Li.sub.2 O 0-2 SrO 0-12 Na.sub.2 O 3.5-7 BaO 0-9 K.sub.2 O 6-8.5 ZnO 0-10 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 10-15 CaO + SrO + BaO + 8-18 ZnO B.sub.2 O.sub.3 9-12 Al.sub.2 O.sub.3 4.5-7 ______________________________________with the proviso that the mole ratio (Li.sub.2 O+Na.sub.2 O+K.sub.2 O):(CaO+SrO+ZnO) is greater than 1.0 and ranges up to about 1.4.

Abstract: Green ceramic formulations comprising a polyisobutylene binder are suitable for tape casting and can be effectively removed during thermal processing in reducing atmospheres. The binder may be removed in substantially dry reducing atmosphere. The tapes may be used for forming ceramic substrates and metallized ceramics such as those used in electronic packaging.

Abstract: The present invention is a composite ceramic structure having a porosity of 5 to 40% by volume comprising particles selected from the group consisting of grains and whiskers of at least one inorganic compound AB, where B is oxygen, nitrogen or carbon and A is any metal so the difference in electronegativity between A and B is less than 1.7; or particles selected from the group consisting of grains and whiskers of an inorganic compound, where there is a difference of 1.7 and higher between the components, and having layers of the inorganic compound AB formed on the surfaces of the particles. The particles are bonded together by silicon nitride particles having an average particle size of less than 0.2 micron.

Abstract: This invention relates to processes for preparing a ceramic article having as its principal crystalline phase a leucite/pollucite solid solution. The process involves the use of a zeolite to form the article. Zeolites which can be used are those that have a SiO.sub.2 /Al.sub.2 O.sub.3 ratio of about 3.5 to about 7.5 such as zeolite Y. The zeolite is exchanged with potassium, rubidium and cesium, then calcined at a temperature of about 900.degree. to about 1100.degree. C. for a time to collapse the zeolite framework and provide an amorphous powder. Next, the amorphous powder is formed into a shaped article and the article is sintered at a temperature of about 1150.degree. to about 1400.degree. C. for a time of about 0.5 to about 12 hours to give a ceramic article whose principal crystalline phase is a leucite/pollucite solid solution, is substantially crack free, has less than 5% porosity, and a coefficient of thermal expansion of about 2.times.10.sup.-6 to about 27.times.10.sup.-60 C.sup.-1.

Abstract: A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.5 and a TCE of less than about 4.0 ppm/c. The composition comprises a mixture of 20-50 wt. % borosilicate glass 40-75 wt. % of a glass selected from the group consisting of glass containing 95-98 wt. % silica, titanium silicate glass and combinations thereof and sufficient amounts of gallium to inhibit the formation of crystalline forms of silica. The composition can be combined with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Abstract: Porcelain compositions suitable for use as porcelain layers on metal base dental restorations have fusion temperatures of about 800.degree. C. and lower. The compositions may be employed as coatings on titanium and titanium alloy bases since the compositions have thermal expansion values close to those of titanium and its alloys. A method is also provided for forming dental restorations with relatively inexpensive and biocompatible metal bases and low fusing dental porcelains.

Abstract: A method and composition for providing cathodic protection to underground steel structures is disclosed in which a composition comprising calcium hydroxide, calcium silicate and calcium nitrite is added to backfill for raising the backfill pH above 8 and an electrical current is applied to polarize the surface of the steel structure whereby the surface of the steel structure is maintained negative relative to the backfill. Magnesium hydroxide and aluminum hydroxide can be used as a substitute for at least a portion of the calcium hydroxide.

Abstract: The ceramic tile using sludge slag of the present invention comprises:______________________________________ sludge slag from 5 to 70 wt. %, agalmatolite from 20 to 90 wt. %, clay from 5 to 50 wt. %, and the balance being incidental impurities. ______________________________________The sludge slag is obtained by separating sludge from sewage, burning the thus separated sludge into ash, melting the resultant ash and solidifying the thus melted ash. The sludge slag consists essentially of: ______________________________________ silicon dioxide (SiO.sub.2) from 10 to 50 wt. %, aluminum oxide (Al.sub.2 O.sub.3) from 3 to 20 wt. %, phosphorous pentoxide (P.sub.2 O.sub.5) from 1 to 30 wt. %, calcium oxide (CaO) from 10 to 70 wt. %, magnesium oxide (MgO) from 0.5 to 20 wt. %, and iron oxide (Fe.sub.2 O.sub.3) from 5 to 25 wt. %.

Abstract: A process for forming a shaped article comprised of mullite whiskers comprising the following steps:a. preparing a mixture of aluminum fluoride and silicon dioxide in a weight ratio of about 7:3;b. firing the mixture in air at a temperature above about 750.degree. C. until complete conversion to topaz takes place;c. mixing the topaz product of step (b) with silicon dioxide in a weight ratio of about 18:1 together with a binder and firing at a temperature of above about 1400.degree. C. until complete conversion to mullite occurs.

Abstract: The invention provides a ceramic composition including as an additive a functionalized colloidal silica sol. The ceramic composition of the invention having an increased green strength.

Abstract: In the low temperature-sintering porcelain components of the present invention, designating as A a group of main components containing 40.0-70.0% by weight of a Si component equivalent to SiO.sub.2, 25.0-55.0% by weight of a Ba component equivalent to BaCO.sub.3, 2.0-10.0% by weight of an Al component equivalent to Al.sub.2 O.sub.3, 1.0-3.0% by weight of a B component equivalent to B.sub.2 O.sub.3, 0.3-3.0% by weight of a Cr component equivalent to Cr.sub.2 O.sub.3, and 0.3-3.0% by weight of a Ca component equivalent to CaCO.sub.3, and designating Pb.sub.3 O.sub.4 as B, the low temperature-sintering porcelain components of the invention are ones which satisfy the following relations:80% by weight .ltoreq.A<100% by weigth and0% by weight <B.ltoreq.20% by weight.

Abstract: An improved gunning composition for use in the steel industry includes between 60-75% by weight of a refractory base material, 10-20% by weight of silicon carbide, 7-15% by weight of ball clay, 4-8% by weight of a silica binder material, and, optionally, 5-10% by weight of a graphite material. The silica binder replaces binders composed of petroleum pitch or clay. The silica binder causes the composition to have (1) better adhesion, (2) less cracking, (3) improved strength, and (4) increased resistance to oxidation, corrosion and erosion.

Abstract: The elastic modulus and density of an amorphous, ceramic article derived from a resinous organosilicon polymer and having a composition consisting essentially of silicon, nitrogen and/or carbon are increased while substantially maintaining or improving tensile strength by heat treating the ceramic article at an elevated temperature under superatmospheric nitrogen pressure to increase its density while avoiding crystallization. During heat treatment, at least some of the conditions of time, temperature, heating rate, cooling rate, pressure and atmosphere are controlled to minimize erosion of the article which could otherwise occur due to the loss to the surrounding atmosphere, as a gas or gaseous component, of at least one of nitrogen, silicon and carbon. The heat treated, ceramic article is amorphous and non-crystalline and has a density substantially greater than 2.5 g/cc together with desirable values of tensile strength and elastic modulus.

Abstract: A cubic boron nitride-containing high-density inorganic composite is prepared by mixing cubic boron nitride with a powdered inorganic compound capable of forming a rigid sintered article having a density of at least 85% and a Vickers hardness of at least 800, which does not promote the conversion of cubic boron nitride into graphite-type phase boron nitride (hBN). The powder mixture is compressed into a mold, and fired at low pressure of between 1,000-2,000 MPa, at a temperature of not more than 1,500.degree. C., under which conditions the cubic boron nitride does not convert to hBN, but is sufficiently metastable to permit the formation of the high-density inorganic composite.

Abstract: A metal oxide dielectric dense body, comprising (I) grains having a predominant crystalline phase (a) a primary metal oxide selected from the group consisting of silicon and magnesium oxide and (b) optionally a secondary metal oxide selected from the group consisting of aluminum and zinc oxide and (II) between about 1 and about 20 atom % bismuth, vanadium, or boron oxide or combinations thereof, discontinuously located at the boundaries of the crystalline grains or as inclusions in the crystalline grains, the atom %'s based on the total atoms of bismuth, vanadium, boron, silicon, magnesium, aluminum, and zinc. The dense body has a density which is at least 95% of theoretical.

Abstract: A living hard tissue replacement is prepared by superplastic forming a ceramic material which contains CaO, SiO.sub.2, and MgO, is substantially free of calcium phosphate, but capable of forming a calcium phosphate base compound upon contact with phosphorus-containing water. A replacement is also prepared by superplastic forming a sintered composite body comprising a calcium phosphate base ceramic matrix and an inorganic filler dispersed therein. Both the replacements are suitable as artificial dental roots and crowns.

Abstract: A silicon nitride powder prepared by nitriding a metallic silicon powder and having the following physical characteristics (1) to (3):(1) the oxygen content in the form of a solid solution is at most 0.5% by weight,(2) the specific surface area is from 6 to 16 m.sup.2 /g, and(3) the content of fine powder of at most 0.2 .mu.m is at most 7% by volume.

Abstract: Novel composite ceramic materials include a boron nitride matrix and an amount of silicon components compatible therewith; such ceramic materials comprise a core volume having an external sheath layer on an outer face surface thereof, with the majority of said silicon values being distributed throughout the external layer.

Abstract: A method for producing a low abrasion calcined kaolin pigment which comprises forming an aqueous pulp of crude kaolin dispersing the pulp by adding thereto sufficient water-soluble organic cationic dispersant to impart a positive zeta potential to said particles and, preferably, an acidic pH to said pulp, removing coarse particles from said dispersed pulp and fractionating the dispersed pulp to separate a fine particle size fraction of mineral particles from coarser particles. The fine particle size fraction is dried, pulverized, calcined and repulverized.

Abstract: Ceramic bodies are bonded together via a layer of an oxidation reaction product of a molten metal, which metal is present in one or both of the ceramic bodies prior to bonding. At least one of the ceramic bodies comprises a ceramic product formed by the oxidation reaction of molten parent metal (e.g., alumina from molten aluminum) and grown as molten metal is transported through, and oxidized on the surface of, its own oxidation product. One or both of the ceramic bodies used in the bonding process contains surface-accessible channels of residual metal, i.e., metal channels which have resulted from molten-metal transport during the ceramic growth process. When the suitably assembled ceramic bodies are heated in the presence of an oxidant at a temperature above the melting point of the residual metal, molten metal at the surface of at least one of the body ceramic bodies reacts with the oxidant to form a layer of oxidation reaction product, which may or may not incorporate at least one filler material.

Abstract: A briquette batch is prepared from a mixture of glass raw materials containing not only sodium hydroxide as a binder, but also calcined plaster.

Abstract: A method of forming high density silica products, and the products formed therefrom, comprising the steps of:a) preparing a fused silica slip having a moisture content less than 25% by weight and fine silica particles of which about 90% are a size less than 55 microns;b) mixing the fused silica slip with coarse silica particles having a gram size greater than Tyler Mesh -4 to form a mixture having between 20-70% coarse particles;c) inserting the mixture into a mold of the product to be formed;d) vibrating the mold for a predetermined period of time sufficient to settle the coarse silica particles in the mold and to facilitate release of air bubbles from the mixture and hardening the mixture by drying to form a molded piece.

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: The invention relates to aqueous organic compositions which find particular utility as binders in the processing stages necessary for the production of ceramic articles. More particularly, the aqueous organic compositions comprise polyethylene copolymers, especially ethylene-acrylic acid copolymers dispersed in water for use as a binding agent for the formation of ceramics, particularly metal oxides such as aluminum oxides. In an exemplary form, the aqueous organic composition combined with the ceramic particulates has a weight ratio of about 10% ceramics and 20% aqueous organic composition, although other mixtures may be formulated without detracting from the beneficial features of the invention.