Abstract: A method is provided for synthesizing PLA/apatite composites with improved mechanical strength. In one aspect, a calcium-phosphate/phosphonate hybrid shell is developed to incorporate more reactive hydroxyl groups onto hydroxyapatite (HA) particles. PLA is covalently bonded to HA calcium phosphate hybrid shell, creating a strong interphase between HA and PLA, thus significantly improve the mechanical strength in comparison to that of non-modified HA.

Abstract: A SiAlON sintered body according to the present invention is represented by Si6-zAlzOzN8-z (0<z?4.2) and has an open porosity of 0.1% or less and a relative density of 99.9% or more. A ratio of a total of intensities of maximum peaks of components other than SiAlON to an intensity of a maximum peak of the SiAlON in an X-ray diffraction diagram is 0.005 or less.

Abstract: A method of making high purity crystalline AlON bodies by synthesizing and calcining AlON powders having less than 80 ppm Si, Mg, Ca, Na, and K impurities. The AION powders are milled to reduce the particle size of the AlON powders using a high purity milling media. An AlON body is formed from the milled AlON powders. Such AlON bodies are particularly suitable for semiconductor process chamber components.

Abstract: A ceramic material for radome is illustrated comprising: —about 80-95% (% wt) of Si3N4; about 5-15% (wt %) of magnesium aluminosilicates including 2.5-12.5% (wt %) of Si02, 0.5-3% (wt %) of MgO and 2-6% (wt %) of Al203; and having a density not lower than 2.5 g/cm3 and a dielectric constant not exceeding 6.5. A process for producing a radome is also illustrated.

Abstract: A method of making a construction comprising a polycrystalline super-hard structure joined to a side surface of an elongate substrate. The method includes: providing a vessel configured for an ultra-high pressure, high temperature furnace, the vessel having an elongate cavity for containing a pre-sinter assembly and defining a longitudinal axis, the cavity having opposite ends connected by a cavity wall. The pre-sinter assembly comprises the substrate, an aggregation comprising a plurality of super-hard grains arranged over at least a part of the side surface of the substrate, and a spacer structure configured for spacing the substrate apart from the cavity wall. The spacer structure comprises material having a Young's modulus of at least 300 GPa.

Abstract: A method of making a body of polycrystalline superhard material comprising placing an aggregated mass of grains of superhard material into a canister, placing a ceramic layer either in direct contact with the aggregated mass of grains of superhard material or in indirect contact therewith, the ceramic layer being spaced from the grains by an interlayer of material when present, the ceramic layer having a surface with surface topology, the surface topology imprinting a pattern in the aggregated mass of grains of superhard material complementary to the surface topology, the ceramic material and the material of the interlayer being such that they do not react chemically with the superhard material and/or a sinter catalyst material for the grains of superhard material. The aggregated mass of grains of superhard material and ceramic layer are subjected to a pressure of greater than 5.

Abstract: The invention relates to a bearing comprising a sintered ceramic body traversed by a hole. According to the invention, the body includes a top surface and a bottom surface each of which includes a functional element communicating with said hole.

Abstract: Methods for threading ceramic materials, such as ceramic materials used for spinal implants or other biomedical implants. In some implementations, an expected rate of shrinkage of the block upon undergoing a firing process may be determined. A scaling factor may then be applied using the expected rate of shrinkage to select a tap having a size larger than a desired thread size. A green block may then be tapped with the selected tap to form a threaded opening in the green block. The block may be machined in order to remove cracks caused by the tapping process and/or to form the block into a desired shape/size. The green block may then be fired, which may result in a reduction of a size of the block and a size of the threaded opening.

Abstract: A tough ultra-high temperature ceramic (UHTC) composite comprises grains of UHTC matrix material, such as HfB2, ZrB2 or other metal boride, carbide, nitride, etc., surrounded by a uniform distribution of acicular high aspect ratio reinforcement ceramic rods or whiskers, such as of SiC, is formed from uniformly mixing a powder of the UHTC material and a pre-ceramic polymer selected to form the desired reinforcement species, then thermally consolidating the mixture by hot pressing. The acicular reinforcement rods may make up from 5 to 30 vol % of the resulting microstructure.

Abstract: The present invention relates to a method of manufacturing a porous pre-sintered granule for a sintered reaction-bonded silicon nitride, to which a pressure forming technology can be applied to obtain a porous sintered reaction-bonded silicon nitride having high porosity and having a structure in which macropores and micropores coexist with each other, and to a porous pre-sintered granule manufactured by the method. The method includes the steps of: granulating a raw material comprising silicon and sintering additives including yttrium, aluminum and at least one alkali earth metal compound; and pre-sintering the granulated raw material at a temperature of 1300˜1375° C. under an inert atmosphere. According to the present invention, a porous pre-sintered granule for porous sintered reaction-bonded silicon nitride, which can increase the air permeability and trapping efficiency by controlling the size of a pore channel such that macropores and micropores coexist, can be manufactured.

Abstract: A precursor tape casting method is one in which chemical precursors are converted into a final chemical phase from green tapes to products. Because chemical precursors are employed rather than the final powder materials, sintering is not required to form the material. Lower annealing temperatures instead of high temperature sintering allow the formation of grains of about 1 to about 100 nanometers in the final material. In addition, when the final material is a magnetic/insulator composite, improved magnetic properties may be obtained.

Abstract: A method of forming a polymer/ceramic composite for use in various purposes. For example, the polymer/ceramic composite may be used in orthopedic procedures for replacing bone material, forming an implant, providing an anchor or other appropriate uses. The polymer/ceramic composite may also include selected characteristics such as a hardness, a strength, a bioabsorbability, a biocompatibility or other appropriate characteristics.

Abstract: There are provided in accordance with embodiments of the invention metal-containing inorganic block copolymers, structures formed by self-assembly of such copolymers, and metal-containing ceramics which may be formed from such copolymers and/or structure. Methods for making such copolymers, structures and ceramics are also provided. Other embodiments are also disclosed.

Abstract: Composite materials containing silicon, titanium, carbon, and nitrogen, formed by spark plasma sintering of ceramic starting materials to a high relative density, demonstrate unusually high electrical conductivity as well as high-performance mechanical and chemical properties including hardness, fracture toughness, and corrosion resistance. This combination of electrical, mechanical, and chemical properties makes these composites useful as electrical conductors in applications where high-performance materials are needed due to exposure to extreme conditions such as high temperatures, mechanical stresses, and corrosive environments.

Abstract: A method for producing ceramic matrix composites wherein the method has the steps of impregnating crystalline silicon carbide fibers coated with an interfacial coating with a ceramic matrix precursor; forming the impregnated fibers into the desired shape; curing the shape; and heating the cured shape to a temperature in the range of greater than 1450° C. to 1800° C. to convert the ceramic matrix precursor into a crystal containing ceramic. A densification step may be optionally carried out until the desired porosity/density of the ceramic matrix composite is achieved.

Abstract: A process for producing crack-free shaped ceramic bodies based on Si/C/N by hot pressing of crosslinked polysilazane powder and subsequent pyrolysis of the hot-pressed shaped body employs a pressing temperature higher than the temperature maximum of the TMA curve of the optimally crosslinked polymer.

Abstract: This invention pertains to a method of forming a fiber-reinforced ceramic matrix composite comprising: (a) impregnating a ceramic fiber coated with at least one layer binary coating comprised of boron nitride and silicon nitride wherein the silicon nitride is applied over the boron nitride with a preceramic composition comprising a curable preceramic polymer; (b) forming the impregnated fibers into a desired shape; (c) curing the formed impregnated fibers; (d) heating the cured impregnated fibers of (c) to a temperature of at least 1000° C. in an inert atmosphere for a time effective to convert the preceramic polymer to a ceramic.

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 process for modifying the surface of a base metal formed from a hard material instead of forming a coating film thereon comprises compacting a powder of a hard material, baking the compacted product, dipping the baked product in an alkoxide containing titanium, and sintering the alkoxide-covered baked product in a nitrogen gas atmosphere. The sintered product has very hard titanium carbide, nitride or carbide-nitride particles deposited on the base metal surface. The particles are partly embedded in the base metal and partly protrude from its surface, and are, therefore, very unlikely to come off, while they withstand a temperature change very well.

Abstract: A method of making a shaped article and composite therefor which includes of a shaped tool, such as a mold and providing a composite of a quartz fabric disposed within a polysilazane which is moldable at a temperature below the curing temperature of the polysilazane and cured by catalyst. The polysilazane 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 polysilazane components. The composite is then cured to hardness by increasing the temperature applied to the composite at a rate of about 10.degree. C./minute to a temperature of about 150.degree. C. and holding that temperature of about 150.degree. C. up to about 4 hours to provide a cured polymer. The cured composite is removed from the tool. The polymer can then be converted to a preceramic by heating the cured polymer to a temperature sufficiently high in an inert atmosphere or ammonia gas for a sufficient time.

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: Small diameter silicon carbide-containing fibers are provided in a bundle such as a fiber tow that can be formed into a structure where the radii of curvature is not limited to 10-20 inches. An aspect of this invention is directed to impregnating the bundles of fibers with the slurry composition to substantially coat the outside surface of an individual fiber within the bundle and to form a complex shaped preform with a mass of continuous fibers.

Abstract: Structural ceramic matrix composite material to be employed as automotive engine parts and the like is provided with erosion-resistant qualities in several ways. For one, an erosion-resistant material is applied to the surface as by plasma spraying. The erosion-resistant material can also be mixed with the fibers of the material, particularly near the surface.

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: In fiber composite ceramic containing reaction sintered SiC as a matrix and having BN-coated SiC continuous fibers as composite fibers, the thickness of the BN coating need not be especially made large, and a sliding effect during growing of cracks can be improved, i.e., breakdown energy can be increased. A method of manufacturing fiber composite ceramic in which large number of BN-coated SiC fibers covered with a BN coating are gathered to form yarns, or yarns are woven to form a two-dimensional or three-dimensional fabric, and a preform is formed by the yarns or the fabric, C powder is arranged in a gap portion between fibers of the preform to form a compact, a molten Si is impregnated into the compact to form an SiC matrix between fibers. A region having a high B concentration is formed around the SiC fibers before the preform is impregnated with the molten Si, and B in the region is solid-solved in Si during reaction sintering to suppress B in the BN-coated SiC fibers from being solid-solved in Si.

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: 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 structural fiber reinforced ceramic matrix composite (FRCMC) material adapted for clutch use. The entirety of the frictional components of a clutch mechanism or only particular components thereof can be made of the FRCMC material. One embodiment has integrally molded fiber reinforced ceramic matrix composite clutch friction pads forming the friction surfaces of metal clutch parts. Clutch components exhibiting a higher temperature and wear-resistance than currently available clutch parts are described. These clutch components and pads exhibit improved performance at high temperatures and are highly wear-resistant in comparison to current clutch components.

Abstract: Boron nitride articles are made by heat treating turbostratic BN powder to reduce its oxygen content to 5-8% (mesographitic BN), washing this heat-treated powder, mixing it with 5-8% amorphous boron, shaping the mixture, explosively compacting the shape by a hydrodynamic method and reaction sintering the compacted shape, to form the article.The article is then buried in a powder mixture of BN and SiC and heat treated, to getter residual B.sub.2 O.sub.3.After this, the article is impregnated with low-viscosity oligomers (MW<1000) of methylsilanes selected to yield a high proportion of SiC on pyrolysis, and the article is heat-treated to fill the pores evenly throughout its thickness with SiC.

Abstract: A ceramic fiber is made by spinning a plurality of polymeric materials each including at least one ceramic precursor into a composite fiber, and then pyrolysing the composite fiber to form a composite ceramic fiber of non-homogeneous composition. A preferred ceramic material for use in this method is made by pyrolysing an organo-metallic compound dispersed in an organic polymer carrier. The principal products are tailored matrix-compatible ceramic fibers for reinforcements, and have a core-sheath structure made by coaxial spinning methods. A core of desired mechanical properties, such as silicon carbide, is given a chemically appropriate surface layer. Transition metals compounds are preferred, in a range of organo-metallic ceramic precursors that include carborane derivatives. Allowed additives include metal-silicon compounds, other ceramics, corresponding metal oxides and elementary metals.

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 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: The invention pertains to a composite ceramic fibre which is made from a self-supporting composite polymeric fibre by the conjugate spinning of at least two dissimilar pre-ceramic polymers in shapes varying from cylindrical to ribbon-like, and pyrolysing the spun fibre to form a composite bilateral, core sheath or matrix-fibril ceramic fibre having regions with ceramic compositions derived from each of the polymers, enabling physical and chemical characteristics to be widely varied for use as matrix reinforcements and other applications. A pyrolysis furnace includes countercurrent controlled atmosphere gas flow for chemically stabilizing or modifying the fibres.