Abstract: A method of unidirectionally aligning the whiskers during tape casting and a sintered silicon nitride laminate of controlled properties and microstructure through alignment of the reinforcing grains fabricated by using the method are disclosed. The whiskers are unidirectionally oriented by placing a row of guides 0.2-0.5 mm apart from each other at exit of the reservoir of the slip containing the whiskers during tape casting. The silicon nitride comprising 10-30 volume % of elongated large grains growing from the .beta.-Si.sub.3 N.sub.4 whiskers and oriented unidirectionally in the fine grained matrix is fully densified by gas pressure sintering at 1900.degree. C. It exhibits a fracture toughness value as high as 9.24 Mpa m normal to the whisker alignment according to the Evans-Charles' method disclosed in the Journal of the American Ceramic Society, 59 [7-8], 371-372 (1976).

Abstract: A method of making a ceramic tube of silicon and silicon carbide comprising the steps of covering a mandrel with carbon fiber material; infiltrating the carbon fiber material with a thermoset resin; curing the resin to render the carbon fiber material rigid and produce a green body; removing the mandrel to produce a free-standing body; treating the free standing body with graphite to fill voids and render the green body gas tight and infiltrating the green body with molten silicon to form a silicon and silicon carbide ceramic tube.

Abstract: A polyvinyl alcohol-based hollow fiber membrane having a ratio between the size of particles of 90% rejection and that of particles of 10% rejection of not more than 5, thus proving to have a sharp fractionating property, is produced by a process which comprises, on producing a polyvinyl alcohol-based hollow fiber membrane by dry-jet wet spinning or wet spinning, using a spinneret having heat insulating structure.

Abstract: A heat-resistant, thermally insulative, ductile port liner for a head of an internal combustion (IC) engine having a tube-shaped structure formed from at least one layer of fiber reinforced ceramic matrix composite (FRCMC) material. The FRCMC material includes a polymer-derived ceramic resin in its ceramic form and fibers. In a first embodiment of the port liner, the tube-shaped structure has one FRCMC layer forming the sole, solid wall of the structure. Whereas, in a second embodiment, the tube-shaped structure has two FRCMC layers forming inner and outer walls of the structure, respectively, with an intervening space separating the inner and outer walls. The intervening space is sealed at both ends. It can be filled with a thermally insulating material, evacuated and held at substantially a vacuum pressure, or filled with a gas. Once the port liner has been formed, it is preferably cast-in-place when the metal head of the IC engine is formed.

Abstract: Ceramic structure having therein reinforcing fibers and backfilled strands s prepared by the arranging tows of fugitive and reinforcing fibers parallel to each other to form a fiber preform, contacting the preform with a matrix precursor whereby the precursor deposits around the fibers, removing the preform from the precursor wherein the fibers are coated with the precursor, drying the preform to solidify the precursor on the fibers and to convert the precursor to a matrix form, calcining the preform to convert the matrix form on the fibers to another matrix form, removing the fugitive fibers from the preform to form channels therein, backfilling the channels with a material, and hot pressing the preform for densification purposes to form the ceramic structure containing spaced fibers and spaced backfilled material strands disposed in the matrix.

Abstract: A method of making a shaped article and composite therefor which comprises of a shaped tool, such as a mold and providing a composite of a quartz fabric disposed within a resin taken from the class consisting of inorganic silicon-based polymers, preferably polycarbosilanes having predominantly hydrogen and/or methyl groupings attached thereto and polysilanes having hydrogen and/or methyl grouping attached thereto, polycarbosilazanes, polyborosilazanes, polyborosilanes and certain polysiloxanes with attached groupings as noted for the similar materials as set forth above, which is moldable at a temperature below the curing temperature of the resin and cured by catalyst. The resin can be optionally filled with particulate material. A compaction pressure is applied to the composite to insure contact of the composite and the tool and prevent loss of less reactive resin components. The composite is then cured to hardness by increasing the temperature applied to the composite at a rate of about 10.degree. C.

Abstract: A ceramic monofilament or multifilament fiber having a tensile strength of at least 100 mPa including PbMO.sub.31, where M is a metallic element or a proportionate combination of various metallic elements which can occupy the "B" position in a perovskite lattice. Processes for producing the fiber are also provided. The fibers are useful as ferroelectric or piezoelectric fibers.

Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.

Abstract: This invention relates to novel ecologically compatible water-based stable mullite precursor sols, mullite composites, and methods for making the same. The mullite precursor sols are synthesized using tetraethoxysilane and aluminum nitrate in water. The tetraethoxysilane is hydrolyzed with water and ammonium hydroxide catalyst to make a silica sol, which is then quenched with an aqueous solution of aluminum nitrate. The mullite precursor sols of the invention may be used to make highly densified ceramic composites.

Abstract: Ceramic structure having porosity of 10-80% is characterized by a solid cmic matrix having therein elongated and parallel channels, the structure is made by a process that includes the steps of:(a) arranging tows of elongated fibers parallel to each other to form a fiber preform,(b) contacting the fiber preform with a matrix precursor whereby the matrix precursor deposits around the fibers,(c) removing the fiber preform from the matrix precursor,(d) drying the fiber preform,(e) calcining the fiber preform,(f) hot pressing the structure containing the fugitive fibers therein, and(g) removing at least some of the fibers to form channels in the structure.

Abstract: A composite fiber spoke vehicular wheel and a method of making the same. The wheel has a hub, a rim, and composite fiber strip spokes. Composite fiber strip spokes wrap around a portion of hub, with opposed ends of composite fiber strip spokes secured to rim.

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: An improved friction material may be made having reinforcing fibers aligned generally perpendicular to the friction surface of said material by forming a paper of fibrous friction materials such that the fibers in the paper are aligned closely to the longitudinal axis of the paper and then folding or cutting the paper into pleats or strips such that the pleats or strips are bonded together with the edges defining the friction surface of the friction body and the fibers perpendicular to that surface.

Abstract: A method of making a mechanically stable, fiber having an inclusion of ion-conducting material which includes the steps of coating a single-crystal or polycrystalline .alpha.-alumina fiber with a zirconia or a hexaluminate precursor, optionally heating the coated fiber to dry the coating, when the coating is applied as a suspension or sol, heating the coated fiber to a temperature of about 1000.degree. to 1800.degree. C. to promote the growth of alpha-alumina toothlike extensions in the coating and epitaxial formation of the zirconia or hexaluminate on the sides of the extensions, embedding the fiber in an .alpha.-alumina matrix material, and heating the resulting fiber-matrix composite to react and texture the coating and densify the assembly.

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: Fiber bundle reinforced composite material useful for various high temperature structural members having excellent strength, toughness and resistance to oxidation and a process for producing the same. The fiber bundle reinforced composite material is reinforced with fiber bundles each having a plurality of continuous inorganic fibers bundled with medium such as carbon, being oriented in one, two or three directions, or randomly in the matrix which is reinforced with nano-sized particles precipitated. The fiber bundle reinforced composite material has a desired orientation of fibers and enables production of fiber bundle reinforced composite members having excellent strength and toughness.

Abstract: Ceramic structure and process for its preparation wherein the structure is omposed of a matrix having therein parallel and spaced reinforcing fibers and strands of backfilled ceramic material, the strands being parallel to the reinforcing fibers; and wherein the process includes the steps of arranging tows of fugitive and reinforcing fibers parallel to each other to form a fiber preform, contacting the preform with a matrix precursor whereby the precursor deposits around the fibers, removing the preform from the precursor wherein the fibers are coated with the precursor, drying the preform to solidify the precursor on the fibers and to convert the precursor to a matrix form, calcining the preform to convert the matrix form on the fibers to another matrix form, removing the fugitive fibers from the preform to form channels therein, backfilling the channels with a material, and hot pressing the preform for densification purposes to form the ceramic structure containing spaced fibers and spaced backfilled materi

Abstract: A method is now disclosed for the making of compressed refractory fiber shapes, e.g., compressed ceramic fiber shapes, having a textured surface and an aggregate body. The shapes can be obtained by molding and therefore may be simple or complex. For the process, small discrete fragments of refractory fiber in accumulated form are suspended in a colloidal dispersion, such as the colloidal dispersion provided by colloidal silica. Colloidal mixtures, as of colloidal silica with colloidal alumina are also most serviceable. The fragments and the dispersion are mildly mixed so as not to thoroughly disperse the fiber fragments, but rather to form globules of the fiber in the resulting blend. The resulting material is shaped, e.g., molded under pressure, and usually dried while under pressure, which drying can be at elevated temperature.

Abstract: Ceramic matrix composites (CMC) of high density, preferably of the type SiC/SiC, are provided by a production process based on the infiltration of ceramic fiber cloths with a polymeric precursor solution containing, as fillers, inert powders having size much lower than the mean distance among the ceramic fibers which are used as basic material for the manufacturing of CMC, typically a nanometric granulometry. Such step is followed by the steps of hardening the cloths, pyrolysis of the polymer and repeated thickenings until the desired density is reached. A possible alternative process comprises a brief (<24 hours) treatment of infiltration of SiC from the vapor phase (CVI) with precursors and typical operative parameters for the deposition of silicon carbide followed by the repeated thickenings.

Abstract: A process comprising the steps of:a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400.degree. C. and 1450.degree. C.,b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbonc) providing a cover mix comprising:i) an alloy comprising a metallic infiltrant and the coating element, andii) a resin,d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body,e) heating the cover mix to a temperature between 1410.degree. C. and 1450.degree. C. to melt the alloy, andf) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.

Abstract: Disclosed is a method of manufacturing aluminum nitride, which comprises the steps of preparing a mixed gas consisting essentially of an ammonia gas and at least 0.5% by volume of a hydrocarbon gas, calcining .gamma.-Al.sub.2 O.sub.3 or a precursor thereof at 300.degree. to 1,100.degree. C. so as to prepare the .gamma.-Al.sub.2 O.sub.3 having a moisture content of 1 weight % or less; heating the calcined .gamma.-Al.sub.2 O.sub.3 in the mixed gas at a temperature of 1,200.degree. to 1,700.degree. C., thereby preparing porous aluminum nitride having a specific surface area of 10 m.sup.2 /g or more; and heat-treating the porous aluminum nitride in an atmosphere of an ammonia gas, or a mixed gas of an ammonia gas and an inert gas, at 1600.degree. to 2000.degree. C., so as to make contents of both carbon and oxygen contained in the aluminum nitride 1 weight % or less.

Abstract: The present invention relates to a method for preparing a ceramic fiber wherein the method comprises (A) forming a green fiber from an alk-1-enyl ether functional siloxane resin of the general formula (R.sup.1 SiO.sub.3/2).sub.q (R.sup.2 SiO.sub.3/2).sub.r (R.sup.1.sub.w R.sup.2.sub.x RSiO.sub.(3-w-x)/2).sub.s (R.sup.1.sub.w R.sup.2.sub.x R.sup.3 SiO.sub.(3-w-x)/2).sub.t wherein R is an alk-1-enyl ether group; each R.sup.1 is selected from an aryl group having from 6 to 10 carbon atoms; each R.sup.2 is selected from an alkyl group having from 1 to 4 carbon atoms; R.sup.3 is an alkenyl group having from 2 to 10 carbon atoms; w has a value of 0, 1 or 2; x has a value of 0, 1, or 2 with the provisio that w+x.ltoreq.2; q has a value of 0 to 0.98; r has a value of 0 to 0.98; s is greater than zero; t.gtoreq.0; s+t=0.02 to 0.5 and q+r+s+t=1; (B) curing the green fiber to render it non-fusible; and (C) heating the non-fusible fiber in an inert environment to a temperature above 800.degree. C.

Abstract: A ceramic matrix composite material comprising a matrix containing silicon carbide as the primary component and silicon nitride as the secondary component is disclosed. The silicon nitride includes not more than 1% by weight of iron and reinforcements mixed and dispersed. The ceramic matrix composite material is manufactured, for example, by forming a matrix containing reaction sintered silicon carbide as the primary component and nitriding the free metal silicon produced in the sintering process so that the free metal silicon will be converted to fine silicon nitride particles. Said metal silicon used for reaction sintering already contains iron. These processes enable the containing of a comparatively large amount of reinforcements, as well as the improvement of heat resistance of the sintered compact and the suppression of the deterioration of reinforcements.

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: A hard-faced ceramic fiber module is formed by providing a ceramic fiber sheet that is folded upon itself to form a first surface having adjacent folds and intermediate valleys by impregnating the first surface with an aqueous colloidal silica suspension, covering said impregnated first surface with a layer of a mixture of ceramic fibers in an aqueous colloidal suspension, compressing said layer, freezing said module and then heating the same to remove substantially all of the water.

Abstract: Disclosed are novel ceramic matrix composites in which coated refractory fibers are imbedded in a ceramic matrix derived from a modified hydrogen silsesquioxane resin.

Abstract: A ceramic-forming prepreg tape is prepared by (a) dispersing in water a ceramic-forming powder and a fiber, (b) flocculating the dispersion by adding a cationic wet strength resin and an anionic polymer, (c) dewatering the flocculated dispersion to form a sheet, (d) wet pressing and drying the sheet, and (e) coating or impregnating the sheet with an adhesive selected from the group consisting of a polymeric ceramic precursor, and a dispersion of an organic binder and the materials used to form the sheet. The tape can be used to form laminates, which are then fired to consolidate the tapes to a ceramic.

Abstract: Fiber reinforced ceramic matrix composites are prepared by coating refractory fibers having a interfacial coating thereon with a curable preceramic polymer having a char which contains greater than about 50% sealant oxide atoms followed by forming the coated fibers into the desired shape, curing the coated fibers to form a pre-preg, heating the pre-preg to form a composite and heating the composite in an oxidizing environment to form an in situ sealant oxide coating on the composite. The resultant composites have good oxidation resistance at high temperature as well as good strength and toughness.

Abstract: A SiC whisker-reinforced ceramic composite is prepared by adding about 0.4 to 1.0% by weight of a nonionic polymer, polyvinylalcohol (PVA) to a heat-treated SiC whisker to obtain a SiC whisker slurry, mixing the SiC whisker slurry with a matrix slurry formed at about pH 4 followed by freeze-drying the resulting slurry mixture to produce granules having a uniform packing structure and hot pressing the granules.

Abstract: A composite and pressureless sintering process for making whisker-reinforced alumina composites using a nitride modifier. The whiskers are milled to an aspect ratio of less than 10. Green preform bodies are surrounded by a carbonaceous material during the sintering process to prevent direct exposure of the body surface to the atmosphere within the sintering furnace during the sintering step.

Abstract: A composite and pressureless sintering process for making whisker-reinforced alumina composites using about 1 to about 7.5 wt. % of a nitride modifier consisting essentially of silicon nitride, aluminum nitride, or mixtures thereof that produces a sintered body having a density of greater than 95% theoretical.

Abstract: A method of manufacturing whisker reinforced ceramic bodies with new and improved properties. By replacing the tool pressing with injection molding, surprisingly a more homogeneous structure and more advantageous whisker orientation has been obtained. By choosing the conditions of the molding, it is possible to control the whisker orientation to get optimal material properties. Bodies according to the invention are particularly suitable for chip forming machining of heat resistant materials.

Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.