Abstract: A method for increasing the porosity and crushability characteristics thereof embodies the firing of a ceramic compact comprising a reactant fugitive filler material and a ceramic material in a controlled atmosphere.

Abstract: A method for simultaneously forming an integral barrier layer on selected external surfaces of a fired alumina-based compound ceramic article and for increasing the porosity and crushability characteristics thereof embodies the sintering of a ceramic compact comprising a reactant fugitive filler material and the alumina-based compound ceramic material in a controlled atmosphere.

Abstract: Method for manufacturing a bone prosthesis made of porous alumina. Calibrated alumina grains are subjected to firing at a temperature lower than their sintering temperature; they are disintegrated, then compressed into a pressed mass, then the latter is subjected to sintering.

Abstract: Disclosed is a process for preparing shaped alumina particles for catalysts or catalyst supports by passing droplets of an aqueous slurry of a rehydratable alumina composition through a shaping medium, such as a column of water-immiscible liquid. The alumina composition undergoes rehydration while being shaped as it passes through the shaping medium, and accordingly, firm, discrete alumina bodies are produced.

Abstract: A method for fabricating a ceramic prosthesis of high aluminum oxide suite for the tibial plateau of a knee joint with the superior (upper) portion of the prosthesis being of a high density Al.sub.2 O.sub.3 having a very low porosity and the inferior (lower) portion being of high density Al.sub.2 O.sub.3 having a high degree of porosity capable of accepting bone growth. The method of fabricating the prosthesis comprises mixing a powdered batch of high aluminum oxide material to produce a viscous slip, adding a foaming agent to the slip, adding a catalyst to the slip to decompose the foaming agent, infiltrating the slip into a sponge, drying the composite, producing a planar surface on the porous layer, fabricating a second denser layer, placing a slurry between the two layers, drying and sintering the laminate.

Abstract: Silicon carbide sintered moldings having a high strength and a high oxidation resistance at high temperatures are produced by mixing SiC matrix powders with a binder consisting of an organosilicon high molecular weight compound having silicon and carbon as the main skeleton components and containing at least one foreign element other than silicon, carbon, hydrogen and oxygen, molding the mixture into the desired shape and baking the formed molding at high temperatures.

Abstract: A method of utilizing sewage and/or industrial, e.g. poisonous sludges for making bricks or other ceramic articles. Sludge is mixed with clay to form a mixture of approximately 30 to 50% sludge. The mixture may then be stored, and is extruded by conventional means. After extrusion and cutting or shaping, the articles are dried in a dryer and fired in a kiln. Preferably, the exhaust gases from the dryer are vented into the kiln as combustion gases, where odors or poisonous compounds of the exhaust air are destroyed. Also, used or waste oil may be added during mixing to lessen odors and to supply extra heat during firing in the kiln. The products so produced are substantially indistinguishable from conventional products, except that their insulating properties are enhanced.

Abstract: This invention relates to the preparation of silica-containing particulate materials and monolithic structures exhibiting high porosity with exceptionally uniform pore size. The bodies are produced through gelation of aqueous alkali metal silicate and/or colloidal silica solutions, optionally contaiing dispersed particulate phases, with organic reagents followed by a leaching step. Uniformity of pore size is achieved through careful control of such variables as the ratio of alkali metal silicate to colloidal silica solutions, the concentration of silica, the amount of dispersed phase employed, and the like.

Abstract: An alumina core for investment casting directionally solidified eutectic and superalloy materials consists of a central portion which has porosity which is continuous throughout. The material of the central portion has a micro-structure which is characteristic of alumina grains which have undergone vapor phase transport action. An outer layer of alumina encompasses the central portion and in integral therewith and contains porosity which is discontinuous.

Abstract: The present invention provides a novel cellular ceramic catalyst support. The support consists of a random-fiber ceramic framework having a high surface area. The support is fabricated by flocking an organic sponge with wood or textile fibers, and impregnating the flocked sponge with a high alumina slurry containing a silicone resin and a flux. The impregnated organic sponge is sintered at a high temperature to burn out the organic sponge material. A fired high-silica glaze can be applied to the sintered article, followed by a second sintering step. A second glaze containing from 10-25 parts by weight CuO and from 10-25 parts by weight ZrO.sub.2, can be applied, followed by a 2000.degree. F. sintering step. The high temperature causes recrystallization of the CuO onto the surface of the catalyst support thereby increasing the surface area. The glazed surface can be plated with copper or nickel and combinations thereof to function as a reducing unit in a catalytic converter.

Abstract: Production of a sintered ceramic dielectric formed from a green sheet having a uniform microporous structure providing uniform dielectric properties and compressibility for lamination of stacked green sheets into a unitary laminate which may be provided with an internal pattern of electrical conductors extending therein. The structure is obtained by blending the ceramic particulate in a solution of a binder resin miscible in a solvent mixture which is formed from a volatile solvent for the binder resin and a less volatile solvent in which the resin is at most only slightly soluble.

Abstract: Ceramic foams possessing controlled permeability and uniformity are prepared by a combined rolling operation of impregnating an open-celled organic polymer foam material possessing a predetermined permeability and resilience with a fluid aqueous slurry of a thixotropic ceramic composition and immediate passage through at least two controlled roll gaps, wherein the rolls are preset to effect a temporary compression ranging from about 50 to 90% for the first pass and 70 to 90% for the second pass. The resulting material is thereby uniformly impregnated with the required amount of slurry, and is then dried and heated to remove the organic foam component. The foams prepared in accordance with the present invention are useful as filters for molten metals, especially aluminum and its alloys.

Abstract: A method for manufacturing porous ceramic products by mixing ceramic material with a fly dust containing silica and metal oxides and having a large specific surface area of at least 20 m.sup.2 /g. The mixture is heated to at least 800.degree. C to convert it into a porous ceramic material. The process is carried out so as to result in either products having mainly closed pores by heating at sintering temperatures or products having mainly open pores by heating at consolidation temperatures. The admixture may be wrapped in a sheet of material which upon heating the admixture to form pores in the material encloses the gases formed at low temperatures but which ruptures at high temperatures to expose the clay to an oxidizing atmosphere.

Abstract: A method for producing porous graphite for use as bone replacement with a structure for osteon penetration. Graphite is produced with ordered circular pores of 100 to 1000 microns in diameter covering at least 25% of the exposed surfaces. A cylindrical fiber is coated with a carbon flour-pitch mix and is then wound on a bobbin in a predetermined manner. The product of winding is dried, pressed, carbonized, and then graphitized. The fibers are removed either chemically or by volatilization during carbonization or graphitization.

Abstract: The present invention resides in an improved molten metal filter and a method of preparing same and a method of filtering molten metal therethrough. The filter is an open cell ceramic foam material having a plurality of interconnected voids surrounded by a web of said ceramic.

Abstract: Disclosed are gasket and seal materials comprising particulate material interconnected and entrapped by fibrillated polytetrafluoroethylene and methods for manufacturing and using them.

Abstract: Disclosed are graphitized hollow spheres and a method for the manufacture thereof which comprises coating a spherical core of foamed polystyrene with carbonaceous powder and a binder, heating the coated core under controlled conditions to decompose the spherical core of foamed polystyrene, and further heating the resultant carbonaceous body at a high temperature.

Abstract: Ceramic foams possessing controlled permeability and uniformity are prepared by the impregnation of an open-celled organic polymer foam material possessing a predetermined permeability and resilience with a aqueous slurry of a thixotropic ceramic composition while shearing said slurry an amount sufficient to maximize said impregnation, and expelling excess slurry from said material by conducting at least two passes of said material through preset rollers to effect a temporary compression ranging from about 50 to 90% for the first pass and 70 to 90% for the second pass. The resulting material is then dried and heated to remove the organic foam component. The foams prepared in accordance with the present invention are useful as filters for molten aluminum.

Abstract: Oxide microspheres having a diameter in the 0.5 to 20 micron range are produced by forming a mixture of urea or melamine and formaldehyde in an aqueous sol containing colloidal oxide particles. Copolymerization of the organic constituents produces coacervation of the organic material into microparticles containing the inorganic material. The organic constituent can be burned out to form a powder of uniform-sized porous microparticles consisting of an interconnected array of inorganic colloidal particles separated by uniform-sized pores.

Abstract: Porous ceramic materials are made by impregnating a foam with a slurry of finely divided ceramic material, drying and firing the foam. Prior to impregnating the foam it is treated so that the particulate material of the slurry will adhere to the foam.

Abstract: A ceramic prosthesis of high aluminum oxide suitable for the tibial plateau of a knee joint with the superior (upper) portion of the prosthesis being of a high density AL.sub.2 O.sub.3 having a very low porosity and the inferior (lower) portion being of high density AL.sub.2 O.sub.3 having a high degree of porosity capable of accepting bone growth.

Abstract: A high temperature insulating structure adapted for use in a vibratile structure such as a manifold reactor or the like for automobiles, said structure consisting of two walls defining therebetween a space filled with heat insulating material, said material being formed by firing a slurry prepared by mixing a water solution of a phosphate compound and a heat resisting material consisting of 20 - 70 % by weight of silicon dioxide, 15 - 80 % by weight of aluminium oxide, and 0 - 30 % by weight of magnesium oxide.

Abstract: This invention relates to an improvement in the process of preparing porous ceramic articles which are formed by blending a composition containing a polyolefin, a ceramic filler and a plasticizer; shaping the blend; extracting the plasticizer and firing the article to remove the polyolefin. The improvement comprises soaking the extracted article in a water solution of a surfactant prior to firing which results in a substantial reduction in the number of cracked pieces when firing many pieces simultaneously.

Abstract: Hollow articles, in particular microballoons, hollow fibers and other shapes, are prepared by dispersing or dissolving a soluble film-forming solid in a core solvent which is normally solid but transformable slowly to gas, shaping the blend while molten, cooling to solidify and slowly removing the solid core material as a gas. The film-forming solid migrates to form a shell having the original core shape and a non-uniform cross-section of an outer skin and an inner sponge lining.

Abstract: An emissions control system for eliminating or substantially reducing the levels of hydrocarbons, carbon monoxide, oxides of nitrogen and other noxious components in the exhaust gas flow from the internal combustion engine of an automotive vehicle or the like to permissible levels. The system includes a reaction device adapted to be connected to the exhaust gas flow from the engine and having one or more ceramic reaction elements therein which cause the undesirable components in the exhaust gas flow to oxidize, disassociate or otherwise become innocuous before being discharged into the atmosphere. An engine driven air pump supplies air under pressure to the reaction device, and a spark plug is mounted in the device and connected to a suitable high voltage source so that a spark is maintained across the electrodes of the spark plug when the engine of the vehicle is either cold or idling, or when the vehicle is decelerating.

Abstract: A porous ceramic monolithic structure prepared by shaping a ceramic filled polyolefinic material containing a plasticizer, shaping, extracting the plasticizer and treating to remove the polyolefin. The monolithic structure is characterized by uniform pore openings. It has uniform channels of an essentially rectangular cross section, laterally through the length of the monolith, varying in size from 0.025 to 0.20 inches.

Abstract: A particle having superior bonding properties comprising crystalline portions connected together by a bonding material. The bonding material is relieved at the surface of the particle to provide capillaries extending into the particle between adjacent crystals. This results in the fusing material having a terminal surface recessed from the surface of the particle. The particle, when added to an elastomeric material, achieves superior mechanical, chemical and vacumatic bond strength as the elastomeric material is anchored to the particles by occupation of the capillaries, achieving increased bonding area.

Abstract: Disclosed herein is a method for making an electrically conductive rigid cellular structure which comprises (i) coating the exposed surface of a porous, heat or solvent-removable substrate with a mixture of aluminum powder and titanate ester, (ii) decomposing the titanate ester of the mixture to effect cohesive binding of the coating, (iii) removing the substrate, and (iv) heating the remaining structure to develop electrical conductivity.

Abstract: Cellular fused silica having a bimodal closed cell structure is produced by mixing finely divided silica with finely divided boron oxynitride as a cellulating agent, and heating the mixture to a temperature of at least the melting point of the silica, whereby the silica melts and is cellulated by gas generated as a result of decomposition of the boron oxynitride. The cellular silica consists of a multiplicity of primary closed cells defined by a matrix consisting essentially of silica, the matrix also containing a multiplicity of secondary macroscopic closed cells which are at least an order of magnitude smaller than the primary cells. Cellular fused silica bodies according to the method of the invention are characterized by superior mechanical strength in addition to extreme whiteness and high purity of color, as well as other desirable properties, and are particularly useful for high temperature thermal insulation. Carefully controlled and defined shapes having very smooth surfaces may be obtained.

Abstract: This disclosure teaches a method of making a silicon carbide article of less than full density. A mixture of silicon carbide particles, silicon particles and a thermosetting polymeric material are molded to form an article as a green body. The green body is pyrolyzed to change the polymer into carbon and the carbon is then changed into silicon carbide by the silicon contained in the mixture.

Abstract: Method and manufacture are provided for preparing a reticulated foam structure by: investing an organic reticulated foam structure with an inorganic composition, which composition is inert under the conditions for forming the reticulated structure; allowing the inorganic suspension to set to form an investment; removing the organic reticulated foam structure; filling the voids of the investment with a fluid composition to form a reticulated casting; and dissolving the investment so as to leave a reticulated foam structure casting.

Abstract: A method of manufacturing an open cellular article constructed of a plurality of spaced walls of relatively weak bondable material defining a plurality of elongated passages therethrough which are filled with a disintegratable filler material having sufficient form and strength initially to maintain the walls in their predetermined precisely spaced relation and after bonding of the walls into an integral unit such filler material being conveniently removable from the article to reestablish the passages between the walls.

Abstract: The invention provides a porous refractory ceramic material having a high surface area per unit volume, a high resistance to sudden temperature variations and a low resistance to fluid flow. The material is a ceramic replica of a body of reticulated organic foam in which the ceramic consists essentially of fibrous material. Any non-fibrous particulate matter present is in an amount which makes no significant contribution to the strength of the body. The material is made by impregnating a body of reticulated organic foam with a slurry of finely-divided inorganic fibres, and drying and firing the thus -impregnated body. The material is of value as a catalyst support and as a facing element of burner assemblies.