Abstract: A thermal shock-resistant alumina-mullite composite material and a preparation method thereof which are capable of concurrently obtaining the compactness of the material and a mullite formation. The material is comprised of 4.about.30 weight % of one aluminum silicate selected from the group consisting of kaolinite, silimanite, and kyanite, 75.about.94 weight % of Al.sub.2 O.sub.3 based on the total amount of Al.sub.2 O.sub.3, and 0.5.about.6 weight % of an alkaline earth metal oxide, wherein the weight ratio of the alkaline earth metal oxide to SiO.sub.2 is 1:2.about.1:3. The composition is first sintered at a temperature of 1450.degree..about.1650.degree. C. for 1.about.5 hours, then cooled down to 1000.degree. C., and then crystallized at a temperature of 1200.degree..about.1500.degree. C. for 1.about.20 hours. This composition is usable to a maximum temperature 300.degree. C.

Abstract: A reaction-formed moulded ceramic body containing mullite is described which is obtainable by heat treating a body moulded from a finely dispersed powder mixture of aluminium, Al.sub.2 O.sub.3 and a material containing Si in an atmosphere containing oxygen. Due to their properties, in particular their low shrinkage of 0 to 4% on average, the moulded bodies are very well suited for use as wear-resistant and/or high temperature-resistant components in the construction of machines, apparatuses and motors, as a cutting tool, as a component for bearings and/or seals and as a functional part in electronic instruments.

Abstract: Plasticized inorganic powder batches comprising a cellulosic binder, water, and at least one inorganic powder exhibiting relatively high water affinity are compounded by combining the inorganic powder, prior to any contact with the water or cellulosic binder, with an organic surface treatment agent to decrease the water affinity thereof; subsequent mixing of the treated powder with the water and the cellulosic binder forms a plasticized inorganic powder batch with improved extrusion, molding, or other shaping characteristics.

Abstract: This invention provides new refractory binder compositions comprising silica and titania which can be used to make ceramic bodies, particularly bricks. The refractory binder compositions comprise about 70 to about 92 wt. % silica (SiO.sub.2) and about 8 to about 30% titania (TiO.sub.2). The refractory binder compositions may further comprise alumina and a metal oxide selected from the group consisting of calcium oxide, strontium oxide, and sodium oxide, and mixtures thereof. The refractory ceramic bodies can be used in hot corrosive/erosive environments such as in fluid bed chlorinators in the manufacture of titanium dioxide.

Abstract: The present invention provides a process for preparing a molybdenum, molybdenum silicide or molybdenum carbide/ceramic admixture, comprising dissolving molybdenum trioxide powder with an alkaline solvent to obtain an aqueous solution of molybdate; incorporating ceramic powder with or without silicon and/or carbon powder into the aqueous solution of molybdate to obtain a slurry; and subjecting the slurry to spray drying and reduction to obtain the admixture. The obtained admixture can be formed and sintered into a nanometer-sized and uniformly dispersed molybdenum, molybdenum silicide or molybdenum carbide/ceramic sintered composites.

Abstract: A monolithic refractory composition, which can be rapidly dried after being mixed with water and applied to a desired portion by casting or spraying to form a furnace wall, and which comprises refractory aggregates, a refractory powder, an aluminum alloy powder and a dispersant, wherein the aluminum alloy powder is contained in an amount of from 0.04 to 5 parts by weight per 100 parts by weight of the total amount of the refractory aggregates and the refractory powder.

Abstract: Mixes suitable for casting or gunning containing a heat-resistant aggregate blend containing at least about 50 wt. % high alumina grain, silicon carbide, and zircon sand, and to the method of utilizing the same to form alkali-resistant linings in high temperature vessels that have improved resistance to build-up.

Abstract: A method of making low-density silica-alumina thermal insulation wherein sulfuric acid is used to leach clay fines from processed Athabasca oil sands. The treated fines are dried and roasted to produce a fine buff to white colored powder with particle sizes that range from forty microns to less than a micron. About 80% of these particles are less than twenty microns. The bulk density of this powder is about fifteen to thirty-five pounds to the cubic-foot (lb./ft.sup.3), compared to silica sand which has a bulk density of 150 lb./ft.sup.3, and alumina which is about 200 lb./ft.sup.3, depending on the grade and method of production.

Abstract: This invention relates to a Hall-Heroult cell for aluminum production comprising a cryolite-resistant liner comprising:i) between 75 weight percent wt % and 95 wt % alumina-silica refractory grain, andii) between 1 wt % and 10 wt % of a sealant selected from the group consisting of feldspar and nepheline.

Abstract: The present invention relates to a process for the preparation of mixed porous oxides with a spherical morphology and the oxides themselves thus obtained.This process consists in emulsifying, in an acid environment, a mixed sol with a dispersing medium, gelifying the microemulsion thus formed by contact with an alkaline solution and subjecting the gel obtained to thermal aging in the presence of the emulsifying liquid and gelation base of the sol or in a water medium, under controlled conditions of pH and temperature.The above mixed oxides can be widely applied as carriers for catalysts or as precursors of ceramic materials.

Abstract: The invention is directed to a non-vapor phase process for forming a metal/ceramic composite containing a relatively inert metal such as silver, copper, or nickel by the reaction of a reactive metal or metal alloy containing the inert metal, and a sacrificial ceramic preform. The resulting metal/ceramic composite is essentially the same shape and dimensions as the sacrificial ceramic preform, and exhibits improved physical and mechanical properties, including improved corrosion and wear resistance.

Abstract: The present invention is a ceramic article of magnesium-X silicate, wherein X represents lithium, sodium, potassium or other monovalent ion from about 0.1 to 2 weight percent, and yttria stabilized zirconia and alumina composite from about 99.9 to 98 weight percent wherein the yttria stabilized zirconia has a molar ratio of yttria to zirconia of from 0.5:99.5 to 5:95 and the alumina comprises from 0.1 to 50 percent of the yttria stabilized zirconia and alumina composite.

Abstract: A method of treating spent potliner material from aluminum reduction cells is disclosed. The spent potliner material is introduced into a sulfuric acid digester to produce a gas component including hydrogen fluoride and hydrogen cyanide and a slurry component including carbon, silica, alumina, sodium sulfate, iron, calcium and magnesium. The gas component is recovered and heated an effective amount to eliminate hydrogen cyanide and produce a remaining gas component including CO.sub.2, H.sub.2 O, nitrogen oxides and HF. The remaining gas component is directed through a water scrubber to form hydrofluoric acid, and the hydrofluoric acid is admixed with aluminum hydroxide to create aluminum fluoride. The slurry component is rinsed with water to separate a first solid fraction containing carbon, alumina and silica from a second liquid faction. The pH of the liquid fraction is adjusted to first create and separate aluminum hydroxide and then to separate sodium sulfate.

Abstract: A whiteware ceramic composition is provided comprising a filler, 4 to 10% by weight of a flux having a median particle size of below 6 microns, a prefired ceramic material milled separately from the other components, and raw clay constituting from 5 to 20% by weight of the composition. Fired whiteware made by firing the composition of the invention is also disclosed.

Abstract: The disclosed invention is directed to novel ceramic compositions, and to stabilizer compositions for use with those ceramic compositions. The ceramic materials are formed of rare earth chromium oxides that include a novel combination of stabilizing compounds. Also, dryer or sterilizer devices which incorporate these ceramic compositions for generating infrared radiation for drying or sterilizing various articles.

Abstract: A porous ceramic material for a slidable member on unit such as a valve unit of a combination faucet. The porous ceramic material comprises a ceramic sintered body which is formed with pores dispersedly located therein. The pores are defined respectively by surface layers forming part of the ceramic sintered body. Each surface layer contains silicon in a content higher than that in other part of the ceramic sintered body. The porous ceramic material is prepared, for example, first by mixing ceramic powder and hollow particles each of which contains silicon so as to obtain a mixture; then by forming the mixture into a predetermined shape to obtain a formed body; and finally by sintering the formed body at a temperature higher than a melting point of each hollow particle to thus obtain the sintered body formed with pores and containing silicon.

Abstract: Provided is a refractory for casting which contains clinker having a mineral crystal phase consisting essentially of mullite and baddeleyite. The refractory for casting has excellent in a thermal-shock resistance, corrosion resistance and strength. The refractory for casting is manufactured from a raw material containing a refractory composition and an organic binder, wherein the refractory composition comprises(a) 3 to 60 wt % of clinker having a mineral crystal phase consisting essentially of mullite and baddeleyite, and containing 5 to 22 wt % of alumina (Al.sub.2 O.sub.3), 38 to 68 wt % of zirconia (ZrO.sub.2) and 27 to 40 wt % of silica;(b) 5 to 40 wt % of at least one carbon-based material selected from the group consisting of graphite and carbon; and(c) at least one refractory element as a balance, selected from the group consisting of alumina, fused silica, zirconia, silicon carbide, mullite and a metal silicon.

Abstract: A castable refractory which comprises a matrix, making up 100 wt % in total, composed of 3-20 wt % of magnesia clinker having a particle diameter smaller than 0.21 mm and containing more than 95 wt % of MgO and 0.5-3.0 wt % of alumina cement in terms of CaO, with the remainder being alumina, and 0.1-3 wt % of ultrafine powder of amorphous silica and 41-100 wt % of alumina coarse grains having a particle diameter of 10-50 mm, both in terms of outer percentage of the amount of the matrix.

Abstract: A castable refractory which comprises a matrix, making up 100 wt % in total, composed of 3-20 wt % of magnesia clinker having a particle diameter smaller than 0.21 mm and containing more than 95 wt % of MgO and 0.5-3.0 wt % of alumina cement in terms of CaO, with the remainder being alumina, and 0.1-3 wt % of ultrafine powder of amorphous silica and 3-9 wt % of alumina coarse grains having a particle diameter of 8-20 mm, both in terms of outer percentage of the amount of the matrix.

Abstract: A method of making an alpha alumina-based ceramic abrasive grain comprising, on a theoretical oxide basis, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, and SiO.sub.2. The abrasive grain has a surface roughness height of greater than about 200 nanometers and a density of greater than about 3.50 g/cm.sup.3. Preferably, the alpha alumina-based ceramic abrasive grain has alpha alumina crystallites having an average crystallite size of less than about 0.5 micrometer (more preferably, less than about 0.3 micrometer). The presence of the SiO.sub.2 in combination with Fe.sub.2 O.sub.3 increases the amount of transgranular fracture of the abrasive grain, reduces the alpha alumina crystallite growth during sintering of the abrasive grain, dilates at least one of the unit cell dimensions of the abrasive grain, and generally improves the grinding performance of the abrasive grain.

Abstract: The present invention pertains to an electrically conductive, dry, refractory ceramic mass based on a refractory oxidic matrix material containing a source of carbon, such as graphite, carbon black or petroleum coke.

Abstract: A glass which contains (1) an alkaline earth oxide that is BaO, SrO, or mures thereof, (2) Al.sub.2 O.sub.3, and (3) SiO.sub.2. The glass is useful as a sintering aid in the preparation of monoclinic BaO.Al.sub.2 O.sub.3.2SiO.sub.2 or monoclinic SrO.Al.sub.2 O.sub.3.2SiO.sub.2 ceramic structures.

Abstract: The present invention relates to ceramics and a method for making ceramics having very little dimensional change after sintering and high dimensional accuracies, so that the characteristics of inorganic functional material are fully maintained and utilized. The ceramics of the present invention comprise grains of inorganic functional material and grains of complex oxide. The pores existing between said grains of inorganic functional material are filled with said grains of complex oxide produced by a sintering reaction between an oxidized metal and an inorganic compound.

Abstract: A spout-filling composition has from about 50% to about 70% by weight magnesium-aluminate spinel aggregate, from about 50% to about 30% by weight quartz sand, and lampblack in an additional amount of from about 0.25% to about 5.00% by weight of the magnesium-aluminate spinel aggregate and quartz sand admixture.

Abstract: An alpha alumina-based ceramic abrasive grain comprising, on a theoretical oxide basis, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, and SiO.sub.2. The abrasive grain has a surface roughness height of greater than about 200 nanometers and a density of greater than about 3.50 g/cm.sup.3. Preferably, the alpha alumina-based ceramic abrasive grain has alpha alumina crystallites having an average crystallite size of less than about 0.5 micrometer (more preferably, less than about 0.3 micrometer). The presence of the SiO.sub.2 in combination with Fe.sub.2 O.sub.3 increases the amount of transgranular fracture of the abrasive grain, reduces the alpha alumina crystallite growth during sintering of the abrasive grain, dilates at least one of the unit cell dimensions of the abrasive grain, and generally improves the grinding performance of the abrasive grain.

Abstract: The single-layer high temperature coating according to the invention, which is applied in particular on a porous substrate, comprises a high silica glaze gel frit, alumina and an emissivity agent consisting of MoSi.sub.2 or Cr.sub.2 O.sub.3, and has the following composition by weight:gel frit: 45 to 55%;MoSi.sub.2 or Cr.sub.2 O.sub.3 : 25 to 50%;Al.sub.2 O.sub.3 : 5 to 20%.

Abstract: The present invention provides a method for preparing a ceramic mixed-oxide of at least two metals including mixing an alloy with a ceramic oxide. The alloy including a metal selected from the group consisting of aluminum, calcium, lithium, magnesium, silicon, titanium, yttrium, and zirconium. The alloy also includes an element that is to be present in the ceramic mixed-oxide. The element is different from the metal and is selected from the group consisting of aluminum, calcium, lithium, magnesium, a combination of magnesium and silicon, silicon, titanium, yttrium, and zirconium. The ceramic oxide includes a metal that is to be present in the ceramic mixed oxide. The alloy and ceramic oxide are co-milled. The mixed and co-milled alloy and ceramic oxide are reaction-sintered, thereby oxidizing the metal and element of the alloy to produce the ceramic mixed-oxide.

Abstract: A composition for manufacturing a fiber-reinforced molded ceramic body comprises a ceramic powder composed primarily of silicon nitride, inorganic fibers and a binder which are added to the ceramic powder. A fiber-reinforced molded ceramic body is manufactured by producing a slurry from such a composition, pouring the slurry into a mold to produce a fiber-reinforced molded ceramic body, and drying the fiber-reinforced molded ceramic body.

Abstract: The castable refractory material comprising as binders, per 100 parts by weight of solid components, (a) 10-30 parts by weight of water-inactive, fine refractory powder, which is a mixture of fine refractory powder having an average diameter of 0.2-0.6 .mu.m and fine refractory powder having an average diameter of 1-10 .mu.m at a ratio of 1:2-2:1; (b) 2-7 parts by weight (as an effective amount) of alumina cement having an average diameter of 3-8 .mu.m, cement clinker minerals thereof comprising CaO.Al.sub.2 O.sub.3 and CaO.2Al.sub.2 O.sub.3, with 12CaO.7Al.sub.2 O.sub.3, if any, in such an amount that a diffraction intensity index of the 12CaO.7Al.sub.2 O.sub.3 at a lattice plane distance D of 2.68 .ANG. is 1 or less assuming that the diffraction intensity index of the CaO.Al.sub.2 O.sub.3 at a lattice plane distance D of 2.96 .ANG. is 100; and (c) 0.4-3 parts by weight of fine amorphous silica powder having an average diameter of 0.5 .mu.

Abstract: An artificial coarse-grain aggregate with particle size of 1-5 mm is prepared by adding alumina particulates as an agent for preventing molten iron erosion, metallic silicon particulates as a pore-size reducing agent, and organic binder to flake graphite with high thermal conductivity or to artificial graphite with particle size of 1 mm or less or to a mixture of both types of graphite, and then by kneading, molding, baking, crushing, and screening. By compounding the coarse-grain aggregate thus manufactured instead of the conventional coarse-grain aggregate of calcined anthracite, artificial graphite, or flake graphite to manufacture carbon refractories, large-sized carbon refractories for blast furnaces, with high thermal conductivity and resistance to molten iron, may be manufactured at high yields. In result, the obtained carbon refractories are favorable as lining material for the basin parts of blast furnaces.

Abstract: Strengthened and toughened ceramic composite bodies are achieved through the use of a silicon boride composition of silicon borides and borides of the form Si-B-C. This strengthening and hardening is achieved when the silicon boride composition is present over a wide range, although a preferred amount is about 20 wt. %. This strengthening and toughening occurs for oxides, carbides, nitrides, and mixtures thereof, for example. One silicon boride composition for this application is silicon hexaboride. Further enhancement is achieved by the addition of up to about 25 wt. % carbon in the silicon hexaboride. Accordingly, the preferred silicon boride composition is a Si-B-C composition, with carbon being added to SiB.sub.6, for example.

Abstract: This invention provides a process for preparing a refractory molded article comprising the steps of (a) forming a molded article matrix from an aggregate and the first binder, (b) impregnating the molded article matrix formed in step (a) with the second binder consisting of an alcoholic solution of one kind or two or more kinds of metal alkoxides selected from alkoxides of metals of Group 4A or Group 4B (excepting carbon) and Group 3A or Group 3B of the periodic table and their partial hydrolysates and an alkaline compound of alkali metal or alkaline earth metal (one kind or a mixture of two or more kinds selected from alkoxides, hydroxides and salts of the metal) and (c) drying and firing the molded article matrix at high temperature and also provides a binder for the preparation of such refractory molded article.

Abstract: Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) protective coatings have been developed for both dense and porous substrates, such as SiC and Si.sub.3 N.sub.4, using a chemical solution processing method involving the hydrolysis and condensation of magnesium, aluminum and titanium precursors. The solution viscosities, pH values, H.sub.2 O/alkoxide molar ratios, and dip coating withdrawal rates which are optimum for crack-free Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) are 1.0 to 6.2 cP, pH 1-4.5, molar ratio 1.5-10, and withdrawal rate of 2.2-8.0 cm/min, respectively. Conversion of the amorphous coating to crystalline Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) is achieved by a succession of calcination below 450.degree. C. and a final heat treatment above 1000.degree. C. for ten hours with controlled heating and cooling rates.

Abstract: A barrier comprising:a) between about 75 w/o and about 95 w/o alumina-silica refractory grain, andb) between about 2 w/o and about 10 w/o of a sealant selected from the group consisting of zinc borate; sulfur; R1 Al.sub.x/2 Si.sub.y/2 O.sub.z/2 and R2 Si.sub.b/2 S.sub.c/2 C.sub.d/2 O.sub.e/2 H.sub.f/2 wherein:i) R1 is selected from the group consisting of Na, K, and Li, and mixtures thereof,ii) x,y and z are integers between 0 and 16,iii) R2 is selected from the group consisting of Ca, Sr and Mg, and mixtures thereof, andiv) b,c,d,e and f are integers between about 0 and 16.

Abstract: An electrorheological fluid that includes a dispersed particulate phase of anhydrous amorphous ceramic particles. The anhydrous amorphous ceramic particles can be of a very precisely tailored composition that is unavailable in crystalline form, for obtaining enhanced electrorheological response. The amorphous particles are substantially free of water when used, and have reduced tendency to absorb water in use. Accordingly, the electrorheological fluid containing anhydrous amorphous electrorheologically responsive ceramic particles has wide applicability for use, and enhanced durability in such use.

Abstract: A mixed powder containing: 5-30 wt % of SiC whiskers; 3-30 wt % of a sintering auxiliary agent composed of one kind or more of oxides of Mg, Si, Ca, Ti, Zr, Cr, Ni, Y and rare earth elements; and an Al.sub.2 O.sub.3 powder as a base material; or further containing 0.5-40 wt % of one kind or more of compounds composed of one kind or more of transient elements in the groups IVa, Va, and VIa of the periodic table and one kind or more of C, N and B, are compacted and subjected to pressureless-sintering in a nitrogen containing inert gas atmosphere at a temperature between 1500.degree. and 1900.degree. C. With this method, the SiC whiskers containing Al.sub.2 O.sub.3 based ceramic material, which is densified and has a sufficient strength and toughness, can be formed in a complex shape and a large size.

Abstract: The invention relates to new curable inorganic resins based on alkali metal boroaluminosilicates, which, before curing, include inorganic elements in the reactive state, in the following proportions, expressed as their molar ratio of oxides:2.ltoreq.SiO.sub.2 /Al.sub.2 O.sub.3 .ltoreq.41.3.ltoreq.X.sub.2 O/Al.sub.2 O.sub.3 .ltoreq.3.810.ltoreq.H.sub.2 O/Al.sub.2 O.sub.3 .ltoreq.280.5<B.sub.2 O.sub.3 /Al.sub.2 O.sub.3 .ltoreq.2.0X.sub.2 O denoting one or more alkali metal oxides chosen from Na.sub.2 O, K.sub.2 O, Li.sub.2 O, and optionally fillers.The invention also relates to the process for the preparation of these new inorganic resins.The cured resins obtained are very useful for manufacturing heat protection materials.

Abstract: A silicon nitride-silicon carbide composite sintered material which comprises 100 parts by weight of a silicon nitride component containing 92 to 99.5 mol % of silicon nitride including excessive oxygen and 0.5 to 8 mol % of the elements of Group IIIa in the Periodic Table as corresponding oxides thereof and 1 to 100 parts by weight of a silicon carbide component in a dispersed state, wherein the silicon nitride component has an average particle size of 1 .mu.m or less and an average aspect ratio of 2 to 10, and the silicon carbide component has an average particle size of 1 .mu.m or less, moreover, the total amount of Al, Mg, Ca respectively contained in the sintered material as calculated as oxides thereof is 0.5% by weight or less, and a manufacturing method thereof.According to the above-mentioned composite sintered material, it becomes possible to suppress deterioration of strength at 1400.degree. C. and realize excellent creep properties.

Abstract: A monolithic refractory powder mixture containing from 2 to 3 wt % of spheroidized refractory particles having a mean particle size of at most 30 .mu.m of at least one member selected from the group consisting of alumina cement, alumina, titania, bauxite, diaspore, mullite, aluminous shale, chamotte, pyrophyllite, sillimanite, andrewsite, silica rock, chromite, spinel, magnesia, zirconia, zircon, chromia, silicon nitride, aluminum nitride, silicon carbide, boron carbide, zirconium boride and titanium boride, and having a cone flow value of at least 180 mm when a refractory mixture having the powder mixture kneaded by an addition of 6 parts by weight of water per 100 parts by weight of the powder mixture, is cast into a cone-shaped mold with a dimension of 70 mm.o slashed.-100 mm.o slashed..times.60 mm and left to stand for 60 seconds without exerting vibration after removing the cone-shaped mold.

Abstract: A refractory of the invention is used in casting operation, which has good spalling resistance and corrosion resistance. The refractory includes: 0.0357-2.6548 wt % of amorphous silica particles having a specific surface area within a range of 15-30 m.sup.2 /g; 8.8495-28.5612 wt % of alumina particles having a particle diameter within a range of 10-50 mm; 1.3986-18.1715 wt % of at least one of fused magnesia and sintered magnesia, which contains 0.6993-10.9041 wt % of magnesia having a maximum particle diameter under 44 .mu.m; 0.6993-13.630 wt % of alumina cement; and 45.4545-88.1417 wt % of alumina. When the refractory is used, at lease one of fused magnesia and sintered magnesia surrounds the alumina particles, which react together to generate spinel to thereby form micro-crack layer around the alumina particles for preventing propagation of cracks in a refractory structure.

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 ceramic fiber yarn, which has higher weaving and knitting performance. The ceramic fiber yarn comprises a group of filaments, the filaments being made by the steps of spinning mother liquid, which comprises colloidal silica and basic aluminum chloride, and firing, the filaments comprising 67-75 wt % of alumina and 25-33 wt % of silica and mainly having polycrystalline transition alumina, and is characterized in that: the loop strength of each the filament, which is measured by a wire having diameter of 0.5 mm, is at or greater than 2.5.times.10.sup.-2 N (N: Newton); and the crystal structure of the filament substantially changes to polycrystalline mullite after heating for 30 minutes at the temperature of 1,400.degree. C.

Abstract: A hydraulic brake piston (11) is formed of a clay based ceramic or conventional ceramic material, such as a kaolin based ceramic with a low thermal conductivity. The piston (11) may be incorporated in a disc brake assembly comprising a caliper body (10) provided with a cylinder which receives the piston (11). Hydraulic brake fluid is introduced under pressure into the space (12) within the body (10) to displace the piston from the body and into contact with a disc pad (14). The ceramic piston retards heat transfer from the disc pad into the brake fluid thus reducing the cause for vapor lock.

Abstract: High zirconia fused cast refractories which include as chemical components of refractories in weight %, 85 through 91% of ZrO.sub.2, 7.0 through 11.2% of SiO.sub.2, 0.85 through 3.0% of Al.sub.2 O.sub.3, 0.05 through 1.0% of P.sub.2 O.sub.5, 0.05 through 1.0% of B.sub.2 O.sub.3 and 0.01 through 0.12% of a summed amount of K.sub.2 O and Na.sub.2 O, wherein the weight % of K.sub.2 O is not smaller than the weight % of Na.sub.2 O.

Abstract: This invention relates to a lead-free ceramic insulator, such as that utilized in headlamp switching assemblies. The composition utilized to make the lead-free ceramic insulator includes low melting glasses which form low-viscosity liquids at low temperatures. The glasses generally contain alkali and/or alkaline earth oxides and boron oxide. Aluminum oxide may be added to compensate for the alkali and alkaline earth containing glasses which are sensitive to corrosion by water. The compositions have a low sintering temperature.

Abstract: There is now provided an oxide based ceramic cutting insert for chipforming machining of heat resistant alloys comprising a ceramic oxide based matrix and 5-50% by volume of homogeneously dispersed whiskers of silicon carbide. The whiskers have an average length of 4-7 .mu.m, with substantially all of the whiskers having a length less than 10 .mu.m.

Abstract: A sintered ceramic article formed mainly of alumina, having a chemical composition of from 1 to 10% by weight of La.sub.2 O.sub.3, from 0.01 to 0.1% by weight of SiO.sub.2, and the balance of Al.sub.2 O.sub.3 and containing these components in the form of corundum (.alpha.-Al.sub.2 O.sub.3) and lanthanum .beta.-alumina (La.sub.2 O.sub.3.llAl.sub.2 O.sub.3) and a method for the production of a sintered ceramic article formed mainly of alumina, comprising the steps of shaping a mixture of Al.sub.2 O.sub.3, La.sub.2 O.sub.3, and SiO.sub.2, calcining the shaped mixture in the air at a temperature in the range of from 600.degree. C. to 1000.degree. C., and further firing the calcined shaped mixture to a temperature in the range of from 1400.degree. C. to 1800.degree. C.

Abstract: In the present invention, there is described a setup for producing a self-supporting ceramic body or ceramic composite by the oxidation of a parent metal to form a polycrystalline ceramic material comprising the oxidation reaction product of said parent metal with an oxidant, including a vapor-phase oxidant, and optionally one or more metallic constituents dispersed throughout the polycrystalline ceramic material. The setup is used with a method which comprises the steps of providing at least a portion of said parent metal with a barrier means at least partially spaced from said parent metal for establishing at least one surface of the ceramic body, and heating said parent metal to a temperature above its melting point but below the melting point of the oxidation reaction product to form a body of molten metal. At that temperature, the molten metal is reacted with the oxidant, thus forming the oxidation reaction product.

Abstract: A novel process for producing highly crystalline, fine .alpha.-alumina is disclosed. Aluminum hydroxide is calcined in the presence of fine silica powder. The obtained alumina is in the alpha form and has a specific surface area of least 10 m.sup.2 /g.

Abstract: Silicon-aluminum mixed oxide powder which is flamehydrolytically produced and has a composition of 65 to 85% by weight Al.sub.2 O.sub.3, remainder SiO.sub.2 and an amorphous structure, in which each primary particle contains components of SiO.sub.2 and of Al.sub.2 O.sub.3, the primary particles are between 7 and 80 nm, preferably 10 and 40 nm in size and the specific surface of the powder is between 20 and 200 m.sup.2 /g. The powder is used for the production of mullite and sintered compacts manufactured from it.