Abstract: A carbon dioxide gas detection element includes a solid electrolyte of a sodium ion conductor made of a ceramic/glass composite material.

Abstract: Prepare sintered aluminum nitride bodies having a thermal conductivity of at least 200 W/m-K by sintering under non-reducing conditions and controlling interrelated parameters such as binder burnout atmosphere, heating rate, sintering temperature, time at sintering temperature, cooling rate and cooling temperature. Sintered bodies having thermal conductivities in excess of 200, especially in excess of 270, W/m-K result from this process.

Abstract: A high-Tc oxide superconductor including Bi, Sr, Ca, Cu, O and at least one of Pb and Al, with a high critical temperature than that of liquid nitrogen. A method for producing the high-Tx oxide superconductor is also disclosed, in which Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3, CuO and PbO or Al.sub.2 O.sub.3 powders are mixed, calcined, ground, cold-pressed and sintered. The calcined mixture may be melted and annealed to obtain a tape-form superconductor.

Abstract: A process for producing mixed oxides containing an alumina species in which a mixture of a hydrated alumina having a specified surface area (average crystal size), a fluid medium and a compound having the formula M.sub.x A.sub.y wherein M is selected from the group consisting of metals, silicon, boron, arsenic and tellurium, A is selected from the group consisting of oxygen and anions, x is from 1 to 4 and y has a value satisfying said formula depending on the valence of M, is formed into a uniform sol, the sol is recovered from the liquid medium and dehydrated, and the dehydrated product is de-agglomerated to produce a mixed oxide having an average particle size of about 1 micron or less.

Abstract: A method of forming a ceramic having a smooth ceramic surface and an assembly for forming ceramics having a flat and smooth ceramic surface are disclosed. A greenware precursor is disposed between a greenware base and a greenware cover. A frame is disposed between the greenware base and greenware cover for limiting compression of the greenware article to an amount which allows formation of a smooth ceramic surface during densification of the greenware precursor. The greenware base, greenware cover and greenware precursor are densified to cause the greenware precursor to form a ceramic having a smooth ceramic surface.

Abstract: An aluminum nitride sintered body having a thermal conductivity of at least 100 W/mK, preferably at least 120 W/mK, more preferably at least 140 W/mK, and most preferably at least 160 W/mK is produced by baking with a sintering additive using an aluminum nitride starting powder of high purity derived by direct nitriding of metallic aluminum. The sintering additive is selected from compounds of Group IIa, IIIa, and IIIb metals of the periodic table and preferably it comprises predominantly Y.sub.2 O.sub.3 or a precursor thereof. In one embodiment, the starting powder and the sintering additive are slurried with a binder and an organic solvent and shaped into a sheet. The sheet, after drying and binder removal, is suitable for use in making multilayered ceramic substrates, ceramic heaters, radiators, and the like.

Abstract: A novel ceramic ferroelectric material having a low dielectric constant, loss and high tunability. The material is a composite comprising Barium Strontium Titanate (BSTO) and a ceramic material having a low dielectric constant. The preferred composite is represented by Ba.sub.1-x Sr.sub.x TiO.sub.3 -Al.sub.2 O.sub.3, wherein x is greater than 0.00, but less than or equal to 0.70, and wherein the percent weight ratio between Ba.sub.1-x Sr.sub.x TiO.sub.3 and Al.sub.2 O.sub.3 ranges from approximately 99%-40% and 1%-60%, respectively. The novel materials possess superior electronic properties; and they may be employed in various antenna systems.

Abstract: A process for producing ceramic flake, fiber and grain materials comprising solidifying a hydrated alumina sol, freeze drying the solidified sol and thereafter sintering the freeze dried material is disclosed. Novel ribbed flake material made by the process of the present invention is also disclosed.

Abstract: Ceramic abrasive grits are formed by an impregnation process that involves preparing an alumina hydrate sol, drying the sol to form a porous solid, crushing the solid to produce particles, calcining the dried particles, preparing a mixture of an additive metal oxide or its precursor in a liquid vehicle, impregnating the mixture into the calcined particles, drying the impregnated particles, calcining the dried impregnated particles, and firing the particles to produce ceramic abrasive grits. The concentration of the modifying additive metal is greater at or near the surface of the grit than at the interior of the grit.

Abstract: A heat conductive aluminum nitride sintered body contains 100 parts by weight of aluminum nitride, at least 0.005 parts by weight and not more than 0.5 parts by weight of carbon, at least 0.01 parts by weight and not more than 15 parts by weight of a rare earth aluminum oxide in terms of the simple substance of a rare earth element, and at least 0.01 parts by weight and not more than 15 parts by weight of at least one element selected from a group of compounds containing elements belonging to the groups IVB, VB and VIB of the periodic table in terms of the simple substance of the element. Such a sintered body has a heat conductivity of at least 100 W/m.multidot.K. and not more than 270 W/m.multidot.K. at room temperature.

Abstract: Fine flaky boehmite particles which have an orthorhombic crystal form and a specified crystal face grown in the form of a flat plate, and a process for the preparation of fine flaky boehmite particles which comprises subjecting aluminum hydroxide or hydrated alumina having a particle size adjusted to the order of submicron to hydrothermal treatment in water or an aqueous alkali solution at a temperature of 150.degree. C. or above and under a pressure of 100 atm or below. The fine flaky boehmite particles are useful as a starting material for the preparation of fine flaky alumina particles or as a filler suitable for a pigment for coating materials, a filler for rubbers and plastics and a coating material for paper making.

Abstract: An abrasive grain for use as a grinding material comprising alpha-alumina crystal particles substantially smaller than 0.5 microns, solidly dissolved with at least one of Ti, Mn, V, Ga, Zn and Rh, and with an a-axis length of the hexagonal unit cell of the alpha-Al.sub.2 O.sub.3 from 4.75892 to 4.76340 angstroms when measured by a powder X-ray diffraction method, and a density of more than 90% of the theoretical value, and an abrasive grain for a grinding material, comprising alpha-alumina crystal particles substantially less than 0.5 microns, solidly dissolved with at least one of Mg, Ni and Co, and with an a-axis length of the hexagonal unit cell of the alpha-Al.sub.2 O.sub.3 from 4.75930 to 4.76340 .ANG. when measured by a powder X-ray diffraction method, and a density of more than 90% of the theoretical value, and further, a grinding wheel and coated cloth manufactured from these abrasive grains.

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: An aqueous slurry of about 100-1000 centipoises viscosity suspending about 200-2000 g/l of aluminum hydroxide particles smaller than 5 .mu.m is spray-dried, and the dried powders are calcined to obtain alumina powders. The alumina powders have a sharp particle size distribution, being suitable for electronic, abrasive and refractory applications.

Abstract: Abrasive material with particularly high abrasive performance is obtained in that the ceramic material contains an additive of 0.01 to 15 percent by weight, preferably 0.1 to 3 percent by weight of a chromium compound.

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: Macrocrystalline .alpha.-alumina hexagonal platelets, well adapted as reinforcing materials and polishing agents, are prepared by calcining admixture of transition or hydrated alumina and a fluorocompound flux, such fluorocompound flux having a melting point of up to 800.degree. C. and, in the molten state, serving to dissolve the transition/hydrated alumina.

Abstract: A heat conductive aluminum nitride sintered body contains 100 parts by weight of aluminum nitride, at least 0.005 parts by weight and not more than 0.5 parts by weight of carbon, at least 0.01 parts by weight and not more than 15 parts by weight of a rare earth aluminum oxide in terms of the simple substance of a rare earth element, and at least 0.01 parts by weight and not more than 15 parts by weight of at least one element selected from a group of compounds containing elements belonging to the groups IVB, VB and VIB of the periodic table in terms of the simple substance of the element. Heat conductivity of the aluminum nitride sintered body is at least 100 W/m.multidot.K and not more than 270 W/m.multidot.K at the ordinary temperature. According to a method of preparing such an aluminum nitride sintered body, at least 0.01 parts by weight and not more than 5 parts by weight of carbon, at least 0.01 parts by weight and not more than 15 parts by weight of an oxide of a rare earth element, and at least 0.

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: The invention relates to refractory materials which comprise:(A) grains of at least one refractory material whose melting point and thermal decomposition temperature are higher than 1700.degree. C.;(B) a binding matrix which binds these grains together and predominantly consists of aluminum nitride AlN of hexagonal structure and/or of at least one of the polytypes of AlN; and(C) hexagonal boron nitride particles and/or crystalline graphite flakes dispersed in the binding matrix.Applications in iron and steel metallurgy, in particular as plates in a slide closure device.

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: Aluminum oxide powders having a high .alpha. proportion, crystallite sizes of approximately 0.1 .mu.m and narrow particle size distribution are prepared from customary Bayer aluminum hydroxide (gibbsite) or from aluminum oxide calcined at a low temperature. The starting material is wet-disagglomerated, mixed with .alpha.-aluminum oxide nuclei, dried and calcined. The calcination produces agglomerates which already have the crystallite size required, and which only need to be disagglomerated to the particle size required. The .alpha.-aluminum oxide powders prepared by such process are particularly suitable as a starting material for the production of high-performance ceramics, for example, of blanking dies.

Abstract: A novel platey alumina with essentially no aggregates, fines or fragments has been obtained. This product proves very advantageous in lapping substrate wafers for microelectronic applications. A process for making such products is also described.

Abstract: A fluid jet orifice and method of making same. The fluid jet orifice comprises an orifice made of sapphire, the sapphire being annealed in a high temperature oxygen atmosphere. Preferably, the high temperature is in a range of approximately 1200.degree. C. to 1700.degree. C., the pressure of the oxygen atmosphere is atmospheric or above, and the annealing time is from approximately 4 to 40 hours.

Abstract: A method of producing a self-supporting ceramic composite body having therein at least one cavity which inversely replicates the geometry of a positive mold of parent metal. The method includes embedding the mold of parent metal within a conformable bed of filler to provide therein a cavity shaped and filled by the mold. The assembly is heated to melt the parent metal mold, e.g., an aluminum parent metal mold, and contacted with an oxidant to oxidize the molten parent metal to form a polycrystalline material which grows through the surrounding bed of filler, the molten metal being drawn through the growing polycrystalline material to be oxidized at the interface between the oxidant and previously formed oxidation reaction product whereby the cavity formerly filled by the mold of parent metal is eventually evacuated of the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold.

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: A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 5.5 and a TCE of less than about 3.5 ppm/.degree.C. The composition comprises a mixture of finely divided particles of 20-80 vol. % borosilicate glass and 20-80 vol. % of Al.sub.x B.sub.y O.sub.z wherein x is in the range of 4 to 22, y is in the range of 2 to 5, and z is in the range of 9 to 36. The Al.sub.x B.sub.y O.sub.z inhibits the formation of crystalline forms of silica. The composition can be used 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: 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: A method for producing a self-supporting ceramic composite body which comprises preparing a polycrystalline material as the oxidation reaction product of a parent metal with a vapor-phase oxidant, comminuting the resulting material to a particulate, forming a permeable mass of said particulate as filler, and infiltrating said particulate with an oxidation reaction product of a parent metal with a vapor-phase oxidant, thereby forming said ceramic composite body.

Abstract: Green bodies suitable for use in manufacturing ceramic articles are provided. The bodies comprise a coherent mass of particles of aluminium oxide free of organic binder and having a fracture stress measured by a biaxial disc flexure test of at least 10 MPa. The particles of aluminium oxide are coated with at least one inorganic oxide or hydrous oxide.The green body can be shaped by drilling, sawing etc. to a desired shape approximating to that of the ceramic article which it is used to produce. Generally such shaping is considerably easier than shaping the finished ceramic article.

Abstract: A resistor composition comprising a pyrochlore-related oxide a glass frit and, anorthite as a finely-divided filler. The resistor composition exhibits high tolerance in respect to firing temperatures. Thick film resistors obtained therefrom by firing on, for example, aluminum oxide substrates, have relatively uniform resistance values, even with inconsistent firing conditions, and have high stability of resistance following laser trimming.

Abstract: This invention relates to infrared slight energy radiation powder and synthetic fiber containing the radiation powder mixed therein and fiber articles made of the synthetic fiber.The radiation powder comprising chiefly alumina, titanium and platinum or palladium, or, alumina, silica and palladium provides sufficient quantities of infrared slight energy radiation having a wide wavelength range. The clothes and bedding made of the synthetic fiber containing infrared slight energy radiation powder are warm and heat-retaining. And the wrapping articles for fresh meat and fish made in relation with the present invention are antibacterial and effective for keeping freshness of the wrapped food.

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: Disclosed is an aluminum nitride sintered body comprising aluminum nitride and a sintering aid, wherein the sintering aid is composed mainly of at least one component selected, as the oxide, from the group consisting of Yb.sub.2 O.sub.3 and Er.sub.2 O.sub.3, and the sintered body contains up to 0.5% by weight of Yb and/or Er as the metal and has a density of 3.2 to 3.3 g/cm.sup.3 and a heat conductivity of at least 170 W/m.multidot.k.If a CaO component is incorporated as the second sintering aid in an amount of up to 0.1% by weight, the heat conductivity is further increased.

Abstract: A method for producing a transparent polycrystalline magnesia-alumina spinel body having high ultraviolet transmissivity and high strength and hardness characteristics is provided. A closed porosity body is formed from a spinel powder preferably having at least minimum purity characteristics. The closed porosity body can be formed by techniques including hot pressing and pressureless sintering. The closed porosity body is subjected to a hot isostatic pressure treatment to reduce residual porosity. The resulting body has high transmissivity of electro-magnetic radiation in the range between about 0.2 microns and about 6 microns and is resistant to abrasion or erosion, has high strength, and does not substantially deteriorate after exposure to ultraviolet light.

Abstract: A refractory for use in firing ceramics has a ceramic coating applied by plasma spraying onto the surface of a heat-resistant lightweight shaped article containing heat-resistant lightweight shaped article containing heat-resistant inorganic fibers. The shaped article is composed of highly aluminous short fibers not longer than 2,000 .mu.m or a mixture thereof with an aluminous refractory powder as bound to each other by means of aluminous binder, the shaped article not containing free silica.

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: This invention provides a transparent aluminum magnesium oxynitride ceramic, wherein greater than 0.5 weight percent of the total ceramic composition is magnesium oxide. The ceramic article of the present invention is useful in applications where it is desirable to have a transparent ceramic including, for example, in orthodontic brackets, ferrules, and gas tight envelopes.

Abstract: A process for manufacturing MgO-based .beta."-alumina sintered bodies from a starting powder comprising an MgO-based .beta."-alumina as a main ingredient, through shaping and firing, in which process shaped bodies before firing contain 0.3.about.5 wt. %, preferably 1.about.3 wt. %, of Na aluminate. The resulting sintered bodies are high in density, ionic conductivity and strength and useful for solid electrolytes, for example, of sodium sulfur cells.

Abstract: An electrical resistive material used for making e.g. a heating element for a thermal printing element. It is a Cr--Al--B--Zr--O alloy and is composed of a quaternary alloy and 15 to 25 at % of oxygen, wherein the quaternary alloy is composed of 2 to 25 at % of zirconium and a ternary alloy containing 35 to 55 at % of chromium, 2 to 23 at % of aluminium and 37 to 58 at % of boron.

Abstract: A method is described for producing hard, dense, finely crystalline fired bodies from alumina gels of solids content greater than 45%, by the use of high pressure in mixing and/or presssure extrusion together with seeding of the gel by submicron alpha alumina particles.

Abstract: Calcium aluminum magnesium phosphate ceramic hard tiles and processes for them are described. The tiles have a density in excess of about 110 pounds per cubic foot, a curl value less than about 20 mils and a flexural strength of at least about 2500 pounds per square inch. To prepare the hard tiles 100 parts (by wt.) of an aluminum phosphate-phosphoric acid solution is mixed with at least 5 parts magnesium oxide and 50-110 parts wollastonite. If the acid has more than 15% by weight water, then mica or vermiculite is added.

Abstract: This invention provides an improved alpha alumina-based ceramic and a method to make the same. The improvement consists of the addition of a chromium-based nucleating agent. Particularly useful embodiments of the improved alpha alumina-based ceramic include abrasive particles and fibers.

Abstract: This invention provides a continuous ceramic oxide fiber comprising Al, Y, and O. In another aspect, a method of making the same is taught. The continuous ceramic oxide fiber is useful, for example, as thermal insulation, as a filter component, and as a reinforcement for structural composites.

Abstract: An .alpha.-alumina-based ceramics material comprising crystals of a particle diameter of no greater than 0.2 .mu.m on an average or a particle diameter of substantially no greater than 0.2 .mu.m, and having a density of no lower than 95% of the theoretical density and a hardness of no lower than 2,000 kg/mm.sup.2, and a method for the production thereof.

Abstract: A process is presented for the fabrication of a metal/ceramic composite by a non-vapor phase oxidation of a molten metal by contacting said molten metal at an elevated temperature with a sacrificial ceramic preform. The shape of the preform is retained but the ceramic preform is reduced, oxidizing the molten metal. A preferred sacrificial ceramic preform is silica, but can also be, for example, mullite, titania or zirconia, and the preferred molten metal is aluminum or an aluminum alloy. Thus, for example, is produced from immersing a silica preform into molten aluminum alloy, an Al/Al.sub.2 O.sub.3 composite metal/ceramic article which does not contain silica or silicon and which is extremely tough.

Abstract: A process for the manufacture of grinding elements composed of aluminum oxide, the process including the steps of (a) mixing aluminum oxide with from 0.5 to 2.5 Wt. % of an organic binder based on the aluminum oxide to provide a mixture; (b) granulating the mixture to form a granulate; (c) molding the granulate into molded pieces having grinding element shapes by applying pressure thereto; and (d) firing the molded pieces at a temperature ranging from 1500.degree. C. to 1850.degree. C. in a vertical kiln to produce grinding elements comprised of aluminum oxide.

Abstract: A process for producing a sintered AlN ceramic body by mixing an organic solution comprising a hydrocarbon solvent and an organometallic compound with AlN powder to produce a slurry, removing the solvent from the slurry to form a mixture of organometallic compound and AlN, forming the mixture into a shape, and heating the shape in a non-oxidizing atmosphere to sintering temperature to obtain densification.

Abstract: A method of producing a refractory material of the non-shaped type is disclosed. Refractory aggregates and a binder are mixed ensuring cohesion by chemical bonding. The mixture is shaped and fired. A charge comprising refractory particles of a polymodal granulometric distribution is mixed with a liquid binder consisting of a mixture in an aqueous medium of polysilicate-based mineral polymers and a mineral polymer comprising sialate groups. The paste obtained is shaped and after hardening of the mixture at a temperature between ambient temperature and 200.degree. C., the hardened mixture is brought to a temperature between 200.degree. and 1300.degree. in order to obtain a refractory material having high mechanical properties, high resistance to thermal shock and resistance to chemical corrosion.