Abstract: A heat-resistant and inorganic shaped article comprising a homogeneous mixture of an alumina powder having an average particle size of 10-50 .mu.m and polycrystalline alumina fibers that are bound together with amorphous silica or alumina. The article has a bulk density of 0.4-1.5 g/cm.sup.3 and a total Al.sub.2 O.sub.3 content of at least 75 wt %.

Abstract: This invention relates to processes for preparing ceramic articles. One process involves taking a potassium exchanged zeolite, the zeolite characterized in that it has a SiO.sub.2 /Al.sub.2 O.sub.3 ratio of 3.5 to about 7.5, and calcining it at a temperature of about 900.degree. to about 1100.degree. C. for a time sufficient to collapse the zeolite framework and provide an amorphous powder. Next, the amorphous powder is formed into a shaped article and the article is sintered at a temperature of about 1150.degree. to about 1400.degree. C. for a time of about 0.5 to about 12 hours to give a ceramic article whose principal crystalline phase is tetragonal leucite, is substantially crack free, and has less than 5% porosity.

Abstract: A metal oxide dielectric dense body, comprising (I) grains having a predominant crystalline phase (a) a primary metal oxide selected from the group consisting of silicon and magnesium oxide and (b) optionally a secondary metal oxide selected from the group consisting of aluminum and zinc oxide and (II) between about 1 and about 20 atom % bismuth, vanadium, or boron oxide or combinations thereof, discontinuously located at the boundaries of the crystalline grains or as inclusions in the crystalline grains, the atom %'s based on the total atoms of bismuth, vanadium, boron, silicon, magnesium, aluminum, and zinc. The dense body has a density which is at least 95% of theoretical.

Abstract: Refractory and electroconductive ceramic compositions having a density higher than 4 g/cm.sup.3, ultimate tensile strength higher than 250 MPa, Vickers microhardness higher than 1000 kg/mm.sup.2 and electric resistivity lower than 600 microohm.cm, essentially consisting of alumina and of a nitride component of at least one transition metal belonging to groups IVB, VB or VIB of the Periodic Chart of the Elements.

Abstract: X-ray amorphous, aluminum oxide which exhibits a specific surface area (BET) according to DIN 66 131 of >10 m.sup.2 /g, an average particle size of .gtoreq.0.1 .mu.m and a water content of >10%. The X-ray amorphous aluminum oxide can be produced by reacting water vapor and vaporous aluminum trichloride in a molar ratio of 1.5 to 10:1, preferably 7.+-.1:1=H.sub.2 O:alCl.sub.3 at a temperature of 200.degree. to 1000.degree. C., preferably 600.degree..+-.50.degree. C. and at a dwell time of >1 sec., preferably 3.5.+-.1 sec. and a partial vacuum of 100.+-.10 mm H.sub.2 O column. By means of calcination thereof an aluminum oxide can be obtained which consists of .gtoreq.90% by weight of .alpha.-aluminum oxide and exhibits a specific surface area (BET) according to DIN 66 131 of >5 m.sup.2 /g and an average particle size of .gtoreq.0.1 .mu.m.

Abstract: Improved alumina-zirconia composite sintered materials with sufficient high mechanical strength and thermal shock resistance as well as excellent hardwearing resistance are made by mixing, heating and melting zirconia and alumina, then the produced melt was quenched, and the resulting solid was ground and milled while adding thereto at least one compound of ceria and/or titania, to an average grain size of from about 0.5 to about 1.5 .mu.m, and subjected the resulting powder to molding and sintering at a temperature of from 1450.degree. to about 1600.degree. C., said zirconia, ceria and titania being employed in the amount of about 10-20%, about 3-7%, and about 15-25% by weight, respectively, plus the balance of alumina. Said sintered materials are useful for employment in structural materials, refractorial materials, erosion resistance materials, cutting tool materials, grinding and polishing materials, etc.

Abstract: The present invention discloses a ceramic precursor composition, comprising (A) 100 parts by weight of at least one fine ceramic powder selected from the group consisting of zirconia and alumina and having an average particle diameter in the range of 0.01 to 2 microns and (B) 10 to 40 parts by weight of a copolymer produced by copolymerizing (a) 10 to 50% by weight of an alkyl or cycloalkyl acrylate having an alkyl group of 1 to 10 carbon atoms or a cycloalkyl group of 4 to 8 carbon atoms, (b) 30 to 80% by weight of an alkyl or cycloalkyl methacrylate having an alkyl group of 1 to 20 carbon atoms or a cycloalkyl group of 4 to 8 carbon atoms, (c) 1 to 5% by weight of a copolymerizable unsaturated carboxylic acid, and (d) 0 to 59% by weight of a hydroxyalkyl acrylate having a hydroxyalkyl group of 2 to 10 carbon atoms (providing that the total amount of the monomers is 100% by weight) and having a number average molecular weight in the range of 10,000 to 100,000 and a glass transition point in the range of -40.

Abstract: Ceramic materials to be insert-cast are disclosed, which each contain not less than 65% by volume of aluminum titanate as a crystalline phase, and have an average particle diameter of crystals thereof being not less than 10 .mu.m, Young's modulus of 50 to 2,000 kgf/mm.sup.2, compression strength of 5 to 40 kgf/mm.sup.2, and porosity of 5 to 35%. Ceramic port liners are also disclosed, which are free from cracking due to compression force during insert-casting, peeling-off during use, and facilitate insert-casting. To attain this, a reinforcement which meets either one or both of requirements that differences in coefficient of thermal expansion at 800.degree. C. and Young's modulus between the reinforcement and a material constituting the port liner body are in a range of .+-.0.1% and in a range of .+-.1,000 kgf/mm.sup.2, respectively, is filled into a depressed portion at an outer peripheral surface of the port liner body to form an integrated structure with a flat or swelled surface.

Abstract: A wear-resistant alumina material is disclosed, as is its preparation by liquid phase sintering a mixture of about 70 to 95 percent by weight of crystalline Al.sub.2 O.sub.3 particles and about 30 to 5 percent by weight of glass phase-forming components in a nitrogenizing atmosphere from which oxygen is substantially excluded. Generally, the resulting material has a 5 Kg Vickers hardness which is at least about 5 percent greater than the hardness of a corresponding alumina material sintered in air.

Abstract: A ceramic cutting insert including whiskers for chip forming machining of steel and having improved mechanical, thermal and wear properties. The insert comprises an oxide based matrix and 5-50% by volume, preferably 10-40% by volume, of homogeneously dispersed whiskers of a solid solution of nitride and oxide of aluminum, preferably of the cubic aluminum oxynitride spinel (AlON). A part of the whiskers constituent may be replaced by whiskers of silicon carbide. The properties of the composite material can be further modified by coating the whisker material with thin layers. The whisker reinforced cutting material shows an improved toughness behavior compared to non-whisker containing ceramic materials.

Abstract: The invention relates to a refractory composition comprising, by weight:(A) at least 70% of an aggregate based on refractory oxides,(B) from 7 to 25% of a matrix consisting of particles distributed between a fine fraction made up of a proportion of at least 95% of its weight of particles from 1 to 20 .mu.m in size, the median diameter of these particles being between 3 and 8 .mu.m, this fine fraction constituting 1 to 24% of the composition, and an ultrafine fraction consisting of a proportion of at least 70% of its weight of particles smaller than 1 .mu.m in size, the median diameter of these particles being between 0.3 and 0.8 .mu.m, this ultrafine fraction constituting 1 to 24% of the composition, the said matrix comprising(i) at least one oxide chosen from the group consisting of Al.sub.2 O.sub.3 and Cr.sub.2 O.sub.

Abstract: There is disclosed a partially sintered setter tile for use in the removal of carbon from multilayer ceramic substrate laminate during the sintering thereof. A multilayer ceramic substrate laminate having metallic lines and vias is provided with a reducible metal oxide in a partially sintered setter tile in close proximity to the substrate laminate. The multilayer ceramic substrate laminate contains a polymeric binder which upon heating depolymerizes into carbon. The substrate laminate and partially sintered setter tile are sintered in an atmosphere which is reducing with respect to the reducible metal oxide and which is oxidizing with respect to the carbon.

Abstract: Sintered microcrystalline ceramic material based on .alpha.-Al.sub.2 O.sub.3 with an addition of 0.01 to 2.0 weight percent of a cerium compound, consisting of a microcrystalline matrix and 0.1 to 30 volume percent whisker-like needles, whereby said cerium compound is mainly present in the needles. The whisker-like needles give this material a special tenacity combined with good abrasive results.

Abstract: A novel process is described for the preparation of monodisperse ceramic ders wherein particulate oxides or hydroxides are obtained by reaction of hydrolysable compounds with water. The reaction is carried out in the presence of a complexing agent and, optionally, a stabilizer.

Abstract: A surface-strengthened composite ceramic material has a ceramic matrix and a refractory phase dispersed at least in and close to the surface of the matrix. The refractory phase includes beta-alumina particles in which larger cations producing a larger molar volume replace sufficient smaller cations in beta-alumina particles in and close to the surface of the composite ceramic material to cause compressive surface stresses which increase the surface strength of the composite ceramic material. The smaller cations are replaced by the larger cations after firing of the composite ceramic material.

Abstract: A method for making composite mullite/cordierite ceramics comprises the steps of:preparing a mullite-intensive sol by mixing alumina and silica sols together at an Al.sub.2 O.sub.3 /SiO.sub.2 molar ratio of 1.37-1.76,preparing a cordierite-intensive sol by mixing alumina, silica and magnesia sols together,gelating a mixture of the mullite- and cordierite-intensive sols obtained at a weight ratio of 80:20-20:80calcinating the thus obtained gel at 1200.degree.-1400.degree. C., andcompacting and sintering the thus calcinated material at 1300.degree.-1450.degree. C.

Abstract: A cubic boron nitride-containing high-density inorganic composite sintered article is produced by a method which essentially consists of preparing a mixture of a cubic boron nitride powder with an inorganic compound powder capable of forming a high-rigidity sintered article under the conditions permitting the cubic boron nitride to remain in a substantially metastable, though not thermodynamically stable, state, a mixture of an inorganic compound-coated cubic boron nitride powder with an inorganic compound powder, or an inorganic compound-coated cubic boron nitride powder, and sintering the mixture of the cubic boron nitride powder with an inorganic compound powder, the mixture of the inorganic compound-coated cubic boron nitride powder with an inorganic compound powder or an inorganic compound-coated cubic boron nitrides powder, under the conditions of not more than 2,000 MPa of pressure and not more than 1,500.degree. C.

Abstract: The ceramic sinter is composed of a metal oxide such as ZrO.sub.2 and 10-90 vol. % of metal fluoride which is selected from the group having not less than 2.5 electronegativity difference between fluoride and the metal element.The ceramic sinter has a thermal expansion coefficient of 15-20.times.10.sup.-6 /.degree.C. and is suitable for bonding with general use metals such as stainless steel to form a composite body of the ceramic sinter and the metal without causing a substantial thermal stress at the juncture thereof.

Abstract: A superconductor metal matrix composite formable into an electrical current carrying material. A superconductive particulate is intermixed with a normal metal matrix, pressed into form and heated to form the composite. The metal matrix surrounds the superconductive particulate to prevent loss of oxygen from the superconductive particulate so the particulate retains its superconductive properties. The metal matrix also becomes superconductive due to proximity effect.

Abstract: An aluminum- and titanium-containing oligomer is prepared by a controlled hydrolysis reaction between a chelated aluminum compound and an organotitanium compound. The oligomer is heated to 800.degree. C. in an oxygen-containing atmosphere to produce .beta.-aluminum titanate.

Abstract: A process for the production of a ceramic polycrystalline abrasive by the sol/gel method is characterized in that an intermediate containing aluminium hydroxide is mixed, dried, calcined and sintered with a further intermediate having different degradation properties. The further intermediate is expediently formed from a calcined aluminium hydroxide.

Abstract: The invention disclosed by this application relates to a novel method of processing sinterable powders into sintered ceramic products. This application also relates to novel forms of aluminum oxide, hydroxylapatite, and tricalcium phosphate ceramic products prepared in accordance with the method of this invention, as well as novel intermediate products useful to prepare the novel ceramic products of this invention.

Abstract: An improved method for producing aluminum titanate powder material for making aluminum titanate ceramics.

Abstract: A ceramic consisting substantially of Al.sub.2 O.sub.3 as ceramic support, ceramic cover layer and/or ceramic supporting structure for heating conductors is described, which is electrochemically stable, which, in other words, does not decompose on application of a heating voltage, even in long-term operation at temperatures above 600.degree.. Such a ceramic exhibits a very small alkali metal content, of less than 0.2% by weight Na.sub.2 O and K.sub.2 O respectively. Particularly favorable processing, in particular pressing properties are exhibited by such a ceramic if it has 2.5 to 10% by weight of barium silicate or strontium silicate fluxes, the proportions of Na.sub.2 O, K.sub.2 O, CaO and MgO together make up less than 1% by weight, and the BaO or SrO:SiO.sub.2 molar ratio is between 2:1 and 1:12.5. Such a ceramic with a BaO:SiO.sub.2 ratio of 2.6:1 parts by weight is electrochemically stable up to approximately 1400.degree. C., and at 1300.degree. C.

Abstract: A catalytic converter utilizing a resilient, flexible shot-free ceramic fiber containing mounting mat for mounting a monolith within a metallic casing is disclosed. The mounting mat may be comprised of shot-free ceramic fibers alone or preferably is comprised of a composite of shot-free ceramic fibers in combination with an intumescent sheet material.

Abstract: A felted mat of ceramic fibers is impregnated with a sol-gel glass binder and is exposed to a low voltage direct current to catalytically gel the binder at ambient temperature and ambient pressure without pH conversion catalysts. The gelled binder can be easily converted to a ceramic thereafter and stabilized by firing above about 525.degree. F.

Abstract: A method for preparing a ceramic suspension using alpha-Al.sub.2 O.sub.3 powder containing agglomerated powder particles includes dissolving ionic or polymeric reagents as additional dispersing agents in water or an organic solvent as a dispersion medium. Alpha-Al.sub.2 O.sub.3 powder is added thereto while being stirred. Ceramic molded articles may be produced from the suspension.

Abstract: A method for producing boehmite, which comprises subjecting aluminum hydroxide dispersed in water to treatment under heat and pressure in the presence of maleic acid and/or malic acid.

Abstract: A process for the production of a precursor which is a polymeric material comprising at least one metallic or non-metallic element, oxygen and carbon and from which a ceramic material, e.g. a carbide, nitride, boride, or silicide, may be produced by pyrolysis, which process comprises reacting(1) a first reactant which comprises a compound or compounds of at least one metallic or non-metallic element having two or more groups reactive with hydroxyl groups, and(2) a second reactant which comprises at least one organic compound having two or more hydroxyl groups,said reaction being effected in a liquid medium in which the reactants are soluble and/or dispersible and in which the polymeric material which is produced by the reaction is insoluble or in which the polymeric material may be caused to be insoluble, precipitating the polymeric material in the liquid medium in particulate form, and recovering the polymeric material from the liquid medium in particulate form.

Abstract: A method is provided of producing a self-supporting ceramic composite structure having one or more encasement members, such as an encasing steel sleeve, joined to it by growth of the ceramic material to engagement surface(s) of the encasement member(s). A parent metal is contacted with a body of filler which is encased by the encasement member(s). The resulting assembly is heated to melt and oxidize the parent metal, e.g., aluminum, to form a polycrystalline material comprising an oxidation reaction product which grows through the body of filler and stops at the engagement surface(s) of the encasement member(s) which thereby determines the surface geometry of the grown ceramic matrix. Upon cooling, the encasement member(s) is shrink-fitted about the ceramic composite body. The invention also provides the resultant articles, for example, a ceramic composite body having a stainless steel member affixed thereto.

Abstract: Polycrystalline ceramic bodies having uniform transparent optical characteristics are produced by providing a green compact, presintering that compact at a temperature in the range from about 1,350.degree. C. to about 1,650.degree. C. until the closed porosity stage is reached, hot isostatic pressing the presintered compact to collapse substantially all pores disposed at grain boundaries and resintering the hot isostatically pressed compact at a temperature in the range from 1,700.degree. C.-1,950.degree. C. to cause grain growth under conditions in which pores, within those grains which are consumed by the growth of other grains, collapse as the grain boundary of the growing grain passes through the location of the pore in the smaller grain being consumed.

Abstract: This invention relates to materials produced by diluting in a solvent a platinum or rhodium catalyzed preceramic mixture of a hydrogen silsesquioxane resin and a metal oxide precursor selected from the group consisting of an aluminum alkoxide, a titanium alkoxide, and a zirconium alkoxide. The preceramic mixture solvent solution is applied to a substrate and ceramified by heating. One or more ceramic coatings containing silicon carbon, silicon nitrogen, or silicon carbon nitrogen can be applied over the ceramified SiO.sub.2 /metal oxide coating. A CVD or PECVD top coating can be applied for further protection. The invention is particularly useful for coating electronic devices.

Abstract: Synthetic stevensite composed of stevensite-type sodium magnesium phylosilicate of which metallic components consist essentially of magnesium, sodium and silicon. The synthetic stevensite is characterized by having an X-ray diffraction peak at a spacing of 16 to 26 .ANG. when treated with ethylene glycol. It can be produced by a process comprising hydrothermally treating an aqueous composition containing basic magnesium carbonate and a silica-sodium component selected from the group consisting of (i) sodium silicate, (ii) sodium silicate and amorphous silica, and (iii) amorphous silica and sodium silicate.

Abstract: Multilayered ceramic substrates having Cu electrode patterns in or on ceramic-glass insulating layers which consist essentially of Al.sub.2 O.sub.3, SiO.sub.2, B.sub.2 O.sub.3, Na.sub.2 O, K.sub.2 O, CaO, MgO and PbO. The methods for manufacturing the substrate comprises thermally treating a laminate of alternately superimposing ceramic-glass insulating layers and CuO-based electrode layers of desired patterns in air or in a molecular oxygen-containing atmosphere to eliminate organic binders from the laminates by burning out, reducing the CuO into metallic Cu at low temperatures in an atmosphere containing hydrogen, and firing the thus reduced laminate in an inert gas such as nitrogen. The firing is effected at 850.degree. to 950.degree. C. The multilayered ceramic substrate may also be obtained by forming ceramic-glass insulating layers and CuO-based electrode layers alternately on a sintered ceramic support, followed by the thermal treatment, reduction and firing set forth above.

Abstract: A ceramic article having good fractured toughness comprising substantially spherical ceramic particles, which may be a ceramic oxide such as zirconia or zirconia combined with yttrium oxide. The ceramic particles are compacted and sintered to a density greater than 90 percent of theoretical density. The article is characterized by a substantially uniform chemical composition and a substantially inclusion-free, homogeneous microstructure, which may be a metastable crystalline phase with less than 10 volume percent monoclinic crystalline phase. The article is produced by dissolving, such as in water, a soluble compound containing a metal, e.g. zirconium, to form a solute. A precipitation agent, such as sodium hydroxide or ammonium hydroxide, is combined with the solute to precipitate a hydrophilic colloid of the metal hydroxide, such as zirconium hydroxide. The precipitate is formed into particles which are rapidly solidified while preventing agglomeration thereof.

Abstract: A ceramic comprising a matrix of Al.sub.2 O.sub.3, ZrO.sub.2 (partially or fully stabilized) or mixtures of Al.sub.2 O.sub.3 and ZrO.sub.2 with strontium aluminate plate-shaped grains distributed throughout the matrix results in a ceramic with high toughness, high strength and good hardness. SrO/Al.sub.2 O.sub.3 molar ratios between 0.02 and 0.20 result in in-situ formation of plate-shaped grains approximately 0.5 .mu.m in thickness and 5.0 .mu.m in breadth in tetragonal zirconia polycrystalline ceramic matrices. The in-situ formation of strontium aluminates allows high volume loading of platelets to occur and high toughness is achieved without the loss of strength. High alumina compositions have the added benefit of higher strength, lower thermal expansion, higher modulus and higher thermal conductivity than zirconia ceramics with comparable toughness.

Abstract: A transparent polycrystalline body having high ultraviolet transmissivity is provided. The body is preferably a sintered magnesia-alumina spinel body having a transmittance of at least 85 percent in the wavelength range from 0.3 microns to 0.8 microns and a transmittance at some wavelength in the wave length range between about 0.2 and about 0.4 microns of at least about 86 percent and a porosity of less than about 0.001 percent. The sintered body is produced by a two-step method comprising forming a closed porosity body from a spinel powder and subjecting the closed porosity body to a hot isostatic pressure treatment. The resulting body has high transmissivity of electromagnetic radiation in the range between about 0.2 microns and about 6 microns, is resistant to abrasion or erosion, does not substantially deteriorate after exposure to ultraviolet light, and has high strength.

Abstract: A method for producing a self-supporting ceramic composite structure which includes a ceramic matrix embedding a filler, includes oxidizing a parent metal to form a polycrystalline material comprising the oxidation reaction product of the parent metal with an oxidant and, optionally, one or more metallic constituents, and the filler embedded by the matrix. The method includes heating a first source of molten parent metal and a source of molten parent metal and contacting the first source of molten parent metal with a permeable bedding of filler. The first source of molten parent metal is reacted with the oxidant to form the oxidation reaction product and is replenished from the reservoir as the reacting continues for a time sufficient to grow the oxidation reaction product to a desired extent and thereby embed at least a portion of the bedding of filler within the oxidation reaction product to form the ceramic composite structure.

Abstract: A sintered alumina article having an excellent flexural strength comprises numerous sintered plate crystalline corundum particles each having cleavage surface planes and accumulated on and bonded to each other in a manner such that the cleavage surface planes of the accumulated plate crystalline particles are substantially in parallel to each other and can be produced by forming the plate crystalline corundum particles into a predetermined shape so that the plate crystalline particles are accumulated in the above-mentioned manner; and by sintering the resultant precursory article at 1500.degree. C. or more under the ambient atmospheric pressure.

Abstract: A ceramic compact having a more excellent high temperature strength, toughness and reliability, which comprises a silicon nitride matrix and ceramic fibers uniformly dispersed in the matrix and orientated in a desired direction, said matrix and fibers being closely bonded by sintering, is provided. This compact is produced, for example, by preparing a shaped body of silicon in which ceramic fibers are uniformly dispersed and then bearing and nitriding the shaped body in a nitrogen atmosphere to form a fiber-reinforced silicon nitride sintered compact.

Abstract: A method of producing a gelled green compact for a thin sintered body is disclosed. The method comprises by steps (a) adding an acid to a solution of metal alkoxide to produce a sol which has the pH controlled within the range from approximately 2 to approximately 3; (b) adding an acid to the sol to lower the pH of the same; (c) adding an alkali to the sol to increase the pH of the same and control the pH within a range from approximately 1.5 to approximately 3; (d) drying the sol; and (e) molding the sol into a gelled green compact. The gelled green compact has a satisfied plasticity.

Abstract: A process for the production of large boehmite crystal aggregates, useful for soft polishing applications is provided herein. A caustic aluminate liquor is contacted with an oxygen-containing gas at elevated temperatures and pressures in the presence of about 1-50 mg/L of copper ions. The liquor is oxidized until a molar ratio of Na.sub.2 O.sub.free to Al.sub.2 O.sub.3 of less than or equal to 1 is achieved, and the oxidized liquor is cooled under quiescent conditions of little or no agitation which causes the crystallization and precipitation or novel large boehmite particles.

Abstract: The invention relates to ceramic composite articles formed by infiltration of a particulate, permeable bed or permeable preform with a polycrystalline matrix a metal-oxidant reaction product. The bed or preform includes a dross material.

Abstract: Shaped articles having improved mechanical properties, e.g., stronger catalysts and catalyst supports, are produced by shaping a mass of particulate material, e.g., ceramic powder, into the form of the desired final article, the particulate material including a microbially produced poly-saccharide compound, and then consolidating the shaped article by heat treating same, e.g., to sintering or calcination temperatures.

Abstract: A transparent polycrystalline body having high ultraviolet transmissivity is provided. The body is preferably a sintered magnesia-alumina spinel body having a transmittance of at least 85 percent in the wavelength range from 0.4 microns to 0.8 microns and a transmittance at some wavelength in the wavelength range between about 0.2 and about 0.4 microns of at least about 86 percent and a porosity of less than about 0.001 percent. The sintered body is produced by a two-step method comprising forming a closed porosity body from a spinel powder and subjecting the closed porosity body to a hot isostatic pressure treatment. The resulting body has high transmissivity of electromagnetic radiation in the range between about 0.2 microns and about 6 microns, is resistant to abrasion or erosion, does not substantially deteriorate after exposure to ultraviolet light, and has high strength. A number of applications of the magnesia-alumina spinel body are disclosed for which the material is advantageous.

Abstract: High strength alumina porcelains for use in insulators are disclosed herein, in which the maximum particle diameter of quartz grians remaining in the porcelains is not more than 40 .mu.m. A process for producing such high strength alumina porcelains for use in insulators comprises the steps of mixing the alumina of a controlled grain size which is decomposed in a single crystalline state and in which the 50% average particle diameter is in a range from 4 to 14 .mu.m, raw materials ground finely which are selected from the group consisting essentially of feldspar, silica sand, and china stone, and clay together, forming the thus obtained mixture, and drying and firing the formed body.

Abstract: Disclosed is a method capable of forming complex green body shapes containing alumina for forming into ceramic products. The method comprises providing a slurry containing alumina powder and an aqueous solution in an amount to provide a high level of solids in the slurry and adding to the slurry rehydratable alumina powder to provide a mix, the rehydratable alumina being present in an amount sufficient to cause the mix to harden. The mix is then permitted to harden to a solid body suitable for firing into a ceramic product.

Abstract: A ceramic composition, comprises a fired product of a starting material mixture containing 10% by weight to 70% by weight of silicon dioxide powder added to mullite powder fired at 1500.degree. C. to 1650.degree. C.

Abstract: Novel calcium dialuminate/hexaluminate ceramic structures in the form of blends, laminates and composites, and processes for making these structures are disclosed. The ceramics of the invention exhibit relatively lower levels of thermal expansion, high strengths, and good thermal shock resistance over wide temperature ranges.

Abstract: The present invention concerns rigid, water-resistant phosphate ceramic materials which may be prepared from components comprising metal oxide, calcium silicate, and phosphoric acid. By prereacting a portion of the metal oxide with the phosphoric acid and/or by adjusting the temperature of the acid solution when it is combined with the other ingredients, the character of the resulting product can be controlled to give foamed or unfoamed phosphate ceramic material.