Abstract: A fracture-resistant, thermally stable intake or exhaust valve for an internal combustion (IC) engine. The valve has a stem portion and a head portion, both of which are formed of fiber reinforced ceramic matrix composite (FRCMC) material. This FRCMC material generally includes a polymer-derived ceramic resin in its ceramic state, fibers, and filler materials. Employing FRCMC material to form the valve is advantageous as FRCMC material is highly temperature resistant and temperature stable, thereby allowing for increased engine operating temperatures. FRCMC material is also ductile, thus making the valve fracture resistant. The FRCMC material is also flaw-insensitive in that any flaw within the structure of the valve will not result in cracking and failure. In addition, FRCMC valves are considerably lighter than the existing metal valves. This provides an opportunity to reduce the weight of the overall valve train, thereby increasing engine performance.

Abstract: A shaped sintered fibrous porous body exhibits a structure with a three-dimensional corrugated or undulating shape and porosity.

Abstract: A method of forming a monolithic, fired ceramic gas diffuser for injecting gas into a molten metal bath includes the steps of: preparing first and second batch materials, depositing the batch materials into a mold to form different portions of the diffuser, and firing the casting to obtain the monolithic diffuser. Various embodiments of the method include vibrating the mold at least while the second batch material is deposited therein, partially freezing a first portion of the casting, and freezing the entire casting prior to firing.

Abstract: A preform for a z-flow honeycomb filter is formed by a pressing process wherein a batch charge is shaped in a press into a preform of finished plug-and-channel configuration, the shaped preform comprising opposing overlapping arrays of closed-end inlet and outlet channels wherein the end closures consist of bridging segments of batch material connected in continuous (seamless) or uninterrupted fashion with the adjoining channel walls.

Abstract: A process for the production of faujasite X agglomerates containing at least 95% of faujasite LSX, that is to say with an Si/Al ratio equal to 1, constituting the active adsorbent. The agglomerate is formed from zeolite LSX and from a binder which can be converted to zeolite, the conversion of which to active zeolite is obtained by conversion to zeolite in a sodium hydroxide/potassium hydroxide or sodium hydroxide liquor.

Abstract: A method for producing hollow fibrous membranes includes the steps of mixing a ceramic powder with a binder to form a paste having a sufficient viscosity to be extruded without heating, characterized in that said binder is a binder dissolved in water or another simple solvent or a thermosetting binder or an inorganic binder or a combination of said binders; extruding the paste to the form of hollow fibers by means of a spinneret; supporting the hollow fibers leaving the spinneret on a roller conveyor comprising a pair of rollers which rotate in opposite directions away from each other where the fibers contact the rollers; and sintering the hollow fibers. These membranes are used for microfiltration, ultrafiltration or gas separation. The fibrous membranes have an external diameter of 0.1-3 mm and a wall thickness of 10-500 &mgr;m.

Abstract: A method for making foam structures suitable for use as mechanical energy absorbers, structural members, filters, catalyst carriers or the like. A composite rod comprising an outer shell and an inner core is formed of respective mixtures of powders. The mixture for the outer shell comprises a sinterable powdered structural material such as ceramics, metals, intermetallics, and a powdered binder such as paraffin, wax or polymer. The inner core comprises a powdered channel-forming filler material such as melamine or polymers, or soluble inorganic compounds or a metal that can differentially be removed from the structural material of the shell. The composite rod may be formed by extrusion. The composite rod is sectioned into a plurality of composite rod segments of predetermined length and a plurality of these segments is assembled in randomly oriented relationship to one another. The assemblage of rod segments is then consolidated, and the binder and filler are then removed, as by heating.

Abstract: A porous composite product comprised of a network of fibers is produced by forming an unsintered preformed network of fibers and a gasifiable structure forming agent, followed by gasification of the structure forming agent prior to sintering of the fibers at appropriate junction points. The preferred structure forming agent is a cellulosic material.

Abstract: The invention is a method of making a novel spherical form of granulated products that can be effectively used in various product forms in drug, fertilizer, foodstuff, feed, agricultural chemical, catalyst, ceramics, powder metallurgy, detergent, plastic, and bio-material fields, for instance, as catalysts, lightweight materials, sound-insulating materials, microcapsules, and lightweight aggregates. To obtain a granulated product which is a spherical solid shell having a spherical space therein, a polymer having high water absorption properties is swollen by the absorption of water therein, and then brought in contact with a powder to form a powder layer all over the surface of the swollen polymer particle. This spherical particle is then dried and fired if necessary.

Abstract: A process for making a low volume fraction preform for a metal matrix composite including the steps of: mixing a reinforcement with a binder and sacrificial fillers to provide a castable slurry; placing the slurry in a mold to provide a green cast preform; drying the green casting to remove any water and/or solvent; firing the green preform at a relatively low temperature to burn off the sacrificial fillers; firing the green preform at an elevated temperature to sinter the binder to bond the reinforcement together. The firing steps include particular combinations of temperature and time to ensure decomposition of the sacrificial filler and sintering without destruction or cracking of the green preform.

Abstract: A process for making bone implants from calcium phosphate powders is disclosed. This process involves selectively fusing layers of calcium powders that have been coated or mixed with polymer binders. The calcium powder mixture may be formed into layers and the polymer fused with a laser. Complex three-dimensional geometrical shapes can be automatically replicated or modified using this approach.

Abstract: A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

Abstract: A process for producing a ceramic network material including the steps of: introducing a ceramic powder into a mold to form a molded material; firing the molded material to form a ceramic, open pore network; infusing the ceramic network with a silane solution; infusing a monomer to at least a portion of the ceramic network; and forming an interpenetrating network. The ceramic network materials may be used as restorative materials and in various devices such as posts, implant abutments, orthodontic brackets and blocks.

Abstract: A method for making very strong gas mantles and other ceramic structures, and the resulting products, are provided. According to the method, an organic or composite structure is first pyrolyzed in the absence of oxygen to remove hydrogen, oxygen and nitrogen, leaving a porous carbon or composite structure, which is then impregnated with a metal compound-containing solution or slurry which is later fired in the presence of an oxidizing atmosphere to produce a refractory metal oxide which has about the same shape as the precursor carbon or composite structure. Due to minimal shrinkage of the mostly carbon or composite precursor, the resulting mantles and other ceramic structures have few defects in the fibers and great strength.

Abstract: A method for preparing a light metal or light metal alloy composite product, wherein (a) an aqueous slurry containing water, a reinforcement powder, a metal powder and an alumina sol binder is prepared; (b) a preform is prepared from the slurry; (c) the preform is sintered; and (d) the sintered preform is impregnated with a melt of a light metal or a light metal alloy to produce a light metal or a light metal alloy based composite product.

Abstract: A method of manufacturing porous ceramic tubes for fuel cells with improved properties and higher manufacturing yield is disclosed. The method involves extruding a closed end fuel cell tube, such as an air electrode of a solid oxide fuel cell, in which the closed end also functions as the sintering support. The resultant fuel cell tube has a superior porosity distribution which allows improved diffusion of oxygen at the closed end of the tube during operation of the fuel cell. Because this region has the highest current density, performance enhancement and improved reliability of the fuel cell tube result. Furthermore, the higher manufacturing yield associated with the present method decreases the overall fuel cell cost.

Abstract: A ceramic filter containing at least one functional material and method of manufacturing, a ceramic filter whose surface through which a liquid to be purified flows into is densest and the average particle size of the filter continuously increases toward the interior thereof, a method of manufacturing the ceramic filter including ultrasonic vibration, an extrusion molding die used to manufacture the ceramic filter and an extrusion molding apparatus using the die.

Abstract: A method for making a molded refractory article including the steps of providing a mold including a master pattern, the mold and master pattern defining a mold cavity; filling the mold cavity with a mixture comprising refractory particles and a heat fugitive binder; placing the assembly of the mold, master pattern and mixture in a furnace; curing the mixture; separating the mold and master pattern from the cured mixture; removing the binder to form a porous structure, sintering the porous structure to provide a porous refractory article and infiltrating the porous refractory article with a filler metal.

Abstract: The present invention relates to a method for producing a porous silicon nitride sintered body having high strength and low thermal conductivity, which comprises of adding more than 10 volume % of rodlike beta-silicon nitride single crystals with a larger mean diameter than that of a silicon nitride raw powder into a mixture comprising the silicon nitride raw powder and a sintering additive, preparing a formed body with rodlike beta-silicon nitride single crystals oriented parallel to the casting plane according to a forming technique such as sheet casting and extrusion forming, sintering said formed body to develop elongated silicon nitride grains from the added rodlike beta-silicon nitride single crystals as nuclei and obtain the sintered body with the elongated grains being dispersed in a complicated state.

Abstract: A method for fabricating a sintered oilless bearing using a correcting rod having a projection correcting portion and a groove forming portion having outer diameters respectively identical to inner diameters of projections and grooves to be formed into the oilless bearing. An upper punch is inserted into the upper portion of the correcting rod for pressing the sintered oilless bearing to allow the inner periphery of the sintered oilless bearing to closely contact the groove forming portion and, simultaneously, fit into the projection forming portion.

Abstract: A composite ceramic board having a low dielectric constant and a low heat expansion coefficient and being suitable for use as a heat-resistant material having a high dimensional accuracy and a low dielectric constant, which is formed of a sintered substrate (II) having a thickness of 0.2 to 10 mm and a thermosetting resin (R) which is integrated into the sintered substrate (II) by being impregnated into pores of the sintered substrate (II) under vacuum and cured, the sintered substrate (II) being a substrate obtained from an inorganic continuous porous sintered body (I) produced by sintering a spherical inorganic powder having an average particle diameter of 0.1 to 10 .mu.m in the presence of a sintering aid, the sintered inorganic powder substantially retaining the spherical forms, the inorganic continuously porous sintered body (I) having an average pore diameter of 0.1 to 10 .mu.m, a true porosity of 8 to 35% and a closed porosity of 2% or less.

Abstract: A method of manufacturing ceramic filter media for water filters involves the steps of mixing a plurality of raw ceramic materials and a plurality of extrusion-aid materials to form a mixture of constituent materials, extruding the constituent materials to form tubular filter media, drying the tubular filter media, and firing the tubular filter media to create ceramic tubular filter media. The step of drying the tubular filter media preferably comprises placing the tubular filter media on top of rotating rollers which dries the tubular filter media evenly and preserves the desired characteristics of the tubular filter media.

Abstract: A method of manufacturing a ceramic article includes the steps of: forming a body of particulate ceramic material having two end portions, a length and a middle portion, wherein a bulk particle density of each of the two end portions is less than a bulk particle density of the middle portion; compressing the body at opposing ends of the body; and thereafter sintering the body to form the ceramic article. The invention may be adapted for production of nuclear fuel pellets.

Abstract: Method of making porous, fibrillose bodies from fibrils bonded together into a self-supporting structure. A mixture of fibrils and a viscous, non-newtonian, liquid vehicle including an organic hydrosorbent and water is (1) injected into a mold, (2) frozen in the mold to form a frozen precursor of the article, (3) ejected from the mold while still frozen, (4) freeze-dried, and (5) finally heated to remove the hydrosorbent and bond the particles together. The process is particularly effective for making fibrillose preforms for infiltrating with metal in the manufacture of metal matrix composites.

Abstract: Novel processes are provided for the production of porous ceramic preforms, metal activated porous ceramic preforms and intermetallic/ceramic/metal composites. These products are all manufactured using processes which are based on tape casting techniques.

Abstract: The present invention relates to a silicon nitride sintered body having a remarkably increased strain-to-fracture, a low elasticity and high strength, characterized by consisting of a layered structure of alternating porous silicon nitride layers 1 to 1000 .mu.m thick with a porosity of 5 to 70 volume % and dense silicon nitride layers 1 to 1000 .mu.m thick with a porosity of less than 5 volume %, being layered as materials with optional tiers. In addition, this invention relates to a method for producing the silicon nitride sintered body as described above, which comprises of forming dense layers and porous layers by sheet casting or extrusion forming so as to prepare the layers to be capable of 1 to 1000 .mu.m thick after sintering, stacking them to obtain layered materials with optional tiers and sintering them at 1600.degree. to 2100 .degree. C. under a nitrogen atmosphere.

Abstract: The present invention is an improved apparatus and method for using a catalyst to remove contaminants from a fluid stream. Catalytic particles are enmeshed within a highly porous expanded polytetrafluoroethylene (PTFE) substrate. The use of an expanded PTFE substrate provides added strength to the substrate and provides open and uniform porosity, thus, assuring proper exchange of molecules between the exterior surface of the substrate and the catalytic particles held within it. As such, the present invention is particularly suitable for use as a cross-flow filter for use in ozone generating office equipment (e.g., an electrostatic photocopy machine) or similar application requiring minimal pressure drop across the filter unit.

Abstract: Fluid permeable candle filter comprising a self supporting tube a filter layer and a filter layer. The self supporting tube comprises ceramic oxide fibers and silicate ceramic oxide bonding phase.

Abstract: A silicon nitride ceramic porous body having excellent acid and alkali resistance, mechanical strength, and durability can be employed as a filter or a catalytic carrier. The silicon nitride porous body contains a plurality of silicon nitride crystal grains with pores formed in grain boundary parts thereof, or includes a body part and a pore part wherein the body part is formed by a plurality of silicon nitride crystal grains and the pore part forms a three-dimensional network structure. The body part is formed by at least 90 vol. % of silicon nitride crystal grains, which are directly bonded to each other. In order to prepare the finished ceramic porous body, a porous body compact which is mainly composed of silicon nitride, is brought into contact with an acid and/or an alkali so that a component other than silicon nitride is partially or entirely dissolved and removed from the compact.

Abstract: A process for producing a ceramic network material from a ceramic suspension includes casting a suspension in a tooth-shaped mold. The suspension includes dispersed alumina particles in a medium containing deionized water with a pH in a range of about 4 to 5 and a concentration of polyvinyl alcohol in a range of about 0.5 to 1% by weight. The process includes the steps of slip casting the suspension in a plaster tooth mold and drying the molded suspension to draw the water from the suspension. The dried suspension then is fired in a furnace at a temperature in a range of about 1000 to 1400.degree. C. to form a ceramic network. After the dried suspension has been fired and excess water and polyvinyl alcohol has been removed from the suspension, lanthanum aluminosilicate glass is infused to a coronal portion of the ceramic network to form a glass layer with a thickness in a range of about 1 to 2 mm within the ceramic network.

Abstract: A method for manufacturing a lightweight foamed ceramic body from components comprising: (a) at least one expandable volcanic mineral; (b) at least one alkaline earth metal oxide, hydroxide, or carbonate, (c) at least one inorganic binder and (d) a foaming stabilizer, the method comprising: (1) sintering and expanding a mixture of components (a) to (d); (2) mixing the sintered and expanded material with water; (3) grinding the mixture of sintered and expanded material with water to form a ground mixture; (4) drying said ground mixture to form a dried mixture; (5) crushing said dried mixture to form a fine powder; (6) shaping said powder into a desired form to form a powder form; and (7) sintering said powder form. The ceramic material is preferably manufactured in a tunnel-type kiln. The resulting foamed ceramic is not only light in weight, but excellent in insulating properties due to its discrete cell of closed cellular structure. The foamed ceramic is useful in structural and building materials.

Abstract: A high-porosity and high-strength porous silicon nitride body comprises columnar silicon nitride grains and an oxide bond phase containing 2 to 15 wt. %, in terms of oxide based on silicon nitride, of at least one rare earth element, and has an SiO.sub.2 /(SiO.sub.2 +rare earth element oxide) weight ratio of 0.012 to 0.65 and an average pore size of at most 3.5 .mu.m. The porous silicon nitride body is produced by compacting comprising a silicon nitride powder, 2 to 15 wt. %, in terms of oxide based on silicon nitride, of at least one rare earth element, and an organic binder while controlling the oxygen content and carbon content of said compact; and sintering said compact in an atmosphere comprising nitrogen at 1,650.degree. to 2,200.degree. C. to obtain a porous body having a three-dimensionally entangled structure made up of columnar silicon nitride grains and an oxide bond phase, and having an SiO.sub.2 /(SiO.sub.2 +rare earth element oxide) weight ratio of 0.012 to 0.65.

Abstract: A ceramic porous body is constituted of ceramic particles which have a substantially continuous, monotonic size distribution in the thickness direction of the porous body.

Abstract: Methods of making fiber reinforced ceramic matrix composite (FRCMC) parts by compression and injection molding. The compression molding method generally includes the initial steps of placing a quantity of bulk molding compound into a female die of a mold, and pressing a male die of the mold onto the female die so as to displace the bulk molding compound throughout a cavity formed between the female and male dies, so as to form the part. The injection molding method general includes an initial step of injecting a quantity of bulk molding compound into a cavity of a mold. In both methods, the bulk molding compound is a mixture which includes pre-ceramic resin, fibers, and, if desired, filler materials. Once the part has been formed by either method, the mold is heated at a temperature and for a time associated with the pre-ceramic resin which polymerizes the resin to form a fiber-reinforced polymer composite structure.

Abstract: The invention relates to a process for the production of spongiosa bone ceramic shaped articles with geometrically irregular shapes and rounded angles and edges, which have no mechanically unstable or inhomogeneous regions. The shaped articles are obtained by treating spongiosa bone ceramic pieces in a ball mill.

Abstract: Ceramic filter of various configuration have been used to filter particulates from hot gases exhausted from coal-fired systems. Prior ceramic cross-flow filters have been favored over other types, but those previously horn have been assemblies of parts somehow fastened together and consequently subject often to distortion or delamination on exposure hot gas in normal use. The present new monolithic, seamless, cross-flow ceramic filters, being of one-piece construction, are not prone to such failure. Further, these new products are made by novel casting process which involves the key steps of demolding the ceramic filter green body so that none of the fragile inner walls of the filter is cracked or broken.

Abstract: In order to produce ceramic hollow fibers, in particular hollow fiber membranes for microfiltration, ultrafiltration and gas separation, a paste is made filling a polymer binder system with a ceramic powder. The paste is processed by extruding through a spinneret to give hollow fibers. The binder system is removed with the aid of thermal diffusion and the powder particles are sintered to each other.

Abstract: An oxide ceramic sintered body of a single component having a purity of at least 99% by weight of titania and a surface with a plurality of pores therein not exceeding 100 pores per square millimeter. The sintered ceramic body is made by preparing a raw titania powder having a purity of at least 99% titania by weight and an average maximum particle diameter of 1 .mu.m, compacting the titania powder to produce a compact, sintering the compact at a temperature in the range of about 1000.degree. C. to about 1300.degree. under ordinary pressure in air, or an inert or reducing atmosphere. The sintered ceramic body may be hot isostatic pressure treated below the sintering temperature in an inert atmosphere under a pressure of at least 500 kg/cm.sup.2 to further reduce the number of pores in the surface.

Abstract: A new class of binders for binding finely divided inert inorganic molding particles when shaped into objects by known mechanical shaping techniques such as injection molding. The novel binders are solid polymer solutions containing a major fraction of a low molecular weight solid relatively non-volatile chemical as solvent in which is substantially dissolved a minor fraction of at least one high molecular weight solid polymer. The solid polymer solution binders when molten are homogeneous solutions and can be readily uniformly mixed with the usual inorganic molding particles into a readily flowable mixture which can be shaped and solidified. When solidified, the polymer and solid chemical remain a substantially homogeneous solution without appreciable phase separation.

Abstract: A method of manufacturing ceramic filter media for water filters involves the steps of mixing a plurality of raw ceramic materials and a plurality of extrusion-aid materials to form a mixture of constituent materials, extruding the constituent materials to form tubular filter media, drying the tubular filter media, and firing the tubular filter media to create ceramic tubular filter media. The step of drying the tubular filter media preferably comprises placing the tubular filter media on top of rotating rollers which dries the tubular filter media evenly and preserves the desired characteristics of the tubular filter media.

Abstract: A method for making a composite ceramic article by infiltration of a sintered ceramic preform with an infiltrate phase. The ceramic preform is made by directionally solidifying a liquid medium containing a dispersion of ceramic particles to produce a green, porous ceramic preform a plurality of interconnected lamelli that are partially separated from one another by complementary interlamellar regions, removing the solidified liquid medium and sintering the ceramic preform. This method may be used to make silicon carbide composites where a silicon carbide preform is first infiltrated with carbon to coat the lamelli of the preform, followed by infiltration of the carbon coated preform with molten silicon, whereby the molten silicon and carbon react to form silicon carbide in the interlamellar regions.