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: Fused cast refractory moldings having a random microstructure, which are near in size and configuration to the desired final shape, and process and apparatus used in their manufacture are described. The process includes rapid melting of the refractory material followed by controlled rapid cooling. Laminated composite fused cast refractories may be produced.

Abstract: Cordierite compositions having increased porosity and improved thermal expansion characteristics are disclosed. The cordierite compositions comprise from about 0.025 to about 1.5 percent by weight germanium dioxide and exhibit reduced CTE. The cordierite compositions are made by heating a mixture of kaolin, talc, alumina, kyanite and germanium dioxide to temperatures of between 1350.degree. and 1475.degree.C. The cordierite compositions are preferably made from a mixture which includes a calcined material, such as calcined talc, so that the mixture is more easily processed and the resulting cordierite compositions are more porous, and thus, more easily coated.

Abstract: An improved chromia-magnesia refractory product of co-fused chromia-magnesia grains bonded by an in situ formed chromia bond is prepared by substantially avoiding the presence of grains that will pass through a screen with openings of 150 microns. The resultant product exhibits improved resistance to silicieous materials such as are present in coal slags.

Abstract: An alumina-spinel monolithic refractory consists essentially of 50-90 percent by weight of alumina clinker, 5-40 percent by weight of MgO--Al.sub.2 O.sub.3 spinel clinker not larger than 1 mm in size and 1-25 percent by weight of alumina cement. Another alumina-spinel monolithic refractory consists essentially of 50-90 percent by weight of alumina clinker, 5-40 percent by weight of MgO--Al.sub.2 O.sub.3 spinel clinker, 1-25 percent by weight of alumina cement and not more than 5 percent by weight of magnesia clinker. The alumina-spinel monolithic refractories are used for lining the inner walls of ladles, vacuum degassing vessels, hot-metal mixers, blast-furnace troughs and their covers, not-metal mixer cars, tundishes and the like.

Abstract: A refractory brick for use in rotary cement kilns has improved properties by the addition of small quantities of MnO.sub.2 to the composition used to form the brick.

Abstract: Essentially spherical particles are disclosed of at least 98.5% alumina having a surface area less than about 1 m.sup.2 /g, an attrition resistance of less than about 0.3 weight percent/hour in an air jet attrition test, a particle size of about 30 to about 110 microns, a tap density of about 1.3 to about 1.9 g/cc, and sufficient porosity to hold catalytic metals in conventional catalytic amounts. The alumina particles are especially suited for use as fluid bed catalyst carriers for use in environments involving the presence of steam, particularly at high temperatures.

Abstract: The present invention is directed toward the improvement of the properties of cordierite sintered structures. The improvement consists essentially of heat treating the calcined kaolin component which when added to the batch of ray materials increases the thermal shock resistance and decreases the coefficient of thermal expansion.

Abstract: Oxidizable metallic particles having a grain size of 60 microns or less of the combination of zinc and magnesium used as heat sources in the flame spraying of refractory masses wherein the zinc magnesium form 5% or less by weight of the total mixture of oxidizable particles and refractory particles, and are used with oxidizable metallic silicon in an amount between 8 and 20% by weight, wherein one or more of silica, alumina, magnesite, chromia and/or zirconia, or silicon carbide form the incombustible refractory particles.

Abstract: In processes of forming a refractory mass on a surface, a mixture of refractory particles and oxidizable particles which react exothermically with oxygen to generate sufficient heat to soften or melt at least the surfaces of the refractory particles are sprayed against that surface to bring about formation of said refractory mass. To promote the reliable and consistent formation of a durable refractory mass, the granulometry of the particles which are sprayed in the mixture is such that the 80% and 20% grain sizes of the refractory particles (that is, the screen mesh sizes G.sub.80 and G.sub.20 through which respectively 80% and 20% by weight of the particles will pass) have a mean greater than the mean of the 80% and 20% grain sizes of the oxidizable particles and the size range spread factor f(G) of the refractory particles is at least 1.

Abstract: Mixed lanthanide-magnesium aluminates and lasers using monocrystals of these aluminates.These lasers in particular incorporate two flash lamps for longitudinally pumping a monocrystalline rod of a magnetoplumbite-aluminate emitting visible or infrared light, amplified between a mirror, a polarizing prism being used for passing to the outside of the laser the amplified light beam. The aluminate is of formula:(La.sub.1-x Tr.sub.x).sub.1-y-v Mg.sub.1-z-t Al.sub.11-u+y+2z/3 Cr.sub.u O.sub.19-t-3v/3.in which Tr represents a) at least one single trivalent substance chosen from among lanthanides, Y.sup.3+, Sc.sup.3+, or b) at least one pair of lanthanides formed from a divalent element and a trivalent element, while retaining the electrical neutrality by adding aluminium or oxygen deficiencies, or any combination of (a) and (b); x is a number such that 0.ltoreq.x<1; y and v are numbers such that 0.ltoreq.y+v.ltoreq.0.4; z and t are numbers such that 0.ltoreq.z+t<1, provided that when z=t=0, y+v is .noteq.

Abstract: New type porous cordierite ceramics having a new characteristic interconnecting open cellular structure and a hollow microspherical cordierite glass powder with a shell devoid of any pores or provided with a few or an abundance of open pores which is used as a starting material for the porous cordierite ceramics. The porous cordierite ceramics are produced by subjecting a starting solution containing an alkyl silicate, an aluminum salt and an magnesium salt optionally with other compounds in an organic or aqueous organic solvent to spray thermal decomposition to prepare the hollow microspherical cordierite glass powder, and then processing the cordierite glass powder to a shaped body after or before an optional heat treatment and firing the shaped body at a temperature below the melting point of cordierite. The porous cordierite ceramics are useful as a carrier for gas chromatography or various chemical reactions.

Abstract: Ceramic moldings containing finely crystalline cordierite are described, which are obtainable by the intensive grinding of precrystallized cordierite powder, mixing the powder with second additive phases of higher modulus of elasticity, shaping the mixture, and sintering the greenware thus obtained in a siliceous atmosphere at temperatures between 900.degree. and 1400.degree. C. The moldings according to the invention have not only good mechanical strengths but also outstanding dielectric and thermal properties; they are therefore especially suitable for use as dielectrics and as thermal insulating components.

Abstract: Disclosed herein is a method of manufacturing dense cordierite, which includes steps of molding a powder mainly consisting of cordierite crystals and having an average particle size of not more than 5 .mu.m, firing a resulting molding at a temperature of from 1,350.degree. to 1,430.degree. C., whereby the sintered body having a porosity of not more than 6% and a bulk specific gravity of not less than 2.4 is obtained.

Abstract: Seeding of beta type alumina compositions in which the alumina in the raw batch is microcrystalline boehmite results in significant increase in hardness, density and strength, as compared to unseeded beta alumina, when fired under similar conditions.

Abstract: The present invention is directed to a ceramic coated metal substrate having improved processibility characteristics in the manufacture of electronic devices, as for example electronic circuits, and to processes for manufacture of such devices.

Abstract: A dielectric ceramic composition for high frequencies consisting essentially of a basic composition expressed by the general formula:xMgO--yAl.sub.2 O.sub.3 --zSiO.sub.2wherein x, y and z are mole percentage of the respective components, x+y+z=100, 65.ltoreq.x.ltoreq.77, 1.ltoreq.y.ltoreq.15, and 8.ltoreq.z.ltoreq.34 and an exclusive additive of 0.1 to 10.0 weight % of Li.sub.2 O. The basic composition has a set of x, y and z falling within an area defined by a polygon ABCD encompassed by the points A, B, C and D in FIG.

Abstract: Heavy ceramic shaped material with a content of at least one of the components magnesia, fired dolomite, chromite and spinel, characterized by a microcrack system substantially homogeneously distributed in the shaped material structure, as well as process for producing such a heavy ceramic shaped material and the use thereof.

Abstract: A composite ceramic extrusion die consisting of a silicon carbide wisker-reinforced cordierite ceramic wherein the predominant matrix phase is cordierite or, preferably, barium-stuffed cordierite having a crystal compositon xBaO.4MgO.(4+x)Al.sub.2 O.sub.3.(10-2x)SiO.sub.2 wherein x ranges from zero up to about 0.5, such extrusion die exhibiting excellent durability under the conditions of non-ferrous metal alloy extrusion at temperatures of 700.degree.-900.degree. C., is described.

Abstract: Refractory compositions which can be gun-applied, or refractory, unfired shapes containing sintered magnesite and/or sintered dolomite as the principal refractory component, 0.5 to 5% by weight of bentonite, 1 to 5% by weight of aluminum sulfate and 0.5 to 5% by weight of an alkaline earth compound, characterized by the fact that they contain magnesium hydroxide and/or caustic-calcined MgO as the alkaline earth compound. The compositions and shapes of the invention have the advantage that they do not exhibit binder migration, and no damping-reduction cracks or chipping occurs therein.

Abstract: Ultrafine particles of ceramic or metallic material are obtained at low temperatures from a nitrate source capable of endothermic decomposition by molecularly combining under a nitrogen atmosphere the nitrate source with an inorganic reducing fuel compound, such as hydrazine, to provide a chemical precursor for the ceramic or metallic material and then exothermically decomposing the precursor in a controlled atmosphere by heating to a temperature up to about 200.degree. C. below the endothermic decomposition temperature of the nitrate source. The nitrate source is a metal nitrate or a mixture of nitrate salts. Ferrite particles are recovered when the nitrate source is a mixture of nitrate salts containing ferric nitrate in a 2:1 molar ratio with at least one additional metal nitrate.

Abstract: A ceramic consisting essentially of from 1 to 15 percent of glass and 99 to 85 percent of a mixture of particulate Al.sub.2 O.sub.3 and particulate ZrO.sub.2 is disclosed. ZrO.sub.2 is present in a sufficient amount, usually from 1/4 to 6 percent based on the weight of the ZrO.sub.2 and Al.sub.2 O.sub.3, to strengthen the ceramic significantly, by comparison with an otherwise identical ceramic where the particulate ZrO.sub.2 is replaced either by the glass or by particulate Al.sub.2 O.sub.3. The glass constitutes a vitreous phase bonding the particulates into a dense, gas impervious structure, and can be a calcium magnesium silicate glass containing from 45 to 80 percent of SiO.sub.2, from 8 to 55 percent of CaO and MgO, and not more than 15 percent of Al.sub.2 O.sub.3.

Abstract: Cordierite series dense and low expansion ceramics have excellent thermal shock resistance property, being airtight, heat resistant and having high dimensional stability at high temperatures can be achieved by incorporating 2-10% by weight of P.sub.2 O.sub.5 in the cordierite ceramic and acid treating the fired or sintered body to selectively remove P.sub.2 O.sub.5 to primarily result in an amount of 0.1% by weight of P.sub.2 O.sub.5 remaining in the sintered body.

Abstract: A silicon nitride sintered body essentially consisting of compounds of Sr, Mg, Ce, Zr and Al in amounts of from 0.1 to 18% by weight when calculated as SrO, from 0.2 to 25% by weight when calculated as MgO, from 0.1 to 20% by weight when calculated as CeO.sub.2, from 0.1 to 15% by weight when calculated as ZrO.sub.2 and from 1 to 20% by weight when calculated as Al.sub.2 O.sub.3, respectively, and the balance being silicon nitride. A method of manufacturing the silicon nitride sintered body is also disclosed. The silicon nitride sintered body has a low thermal conductivity while high mechanical strength and high fracture toughness being maintained.

Abstract: A silicon nitride sintered body essentially consisting of compounds of Mg, Sr, Ce and Al in amounts of from 0.5 to 5% by weight when calculated as MgO, from 0.5 to 5% by weight when calculated as SrO, from 1 to 10% by weight when calculated as CeO.sub.2 and from 1 to 20% by weight when calculated as Al.sub.2 O.sub.3, respectively, and the balance being silicon nitride. A method of manufacturing the silicon nitride sintered body is also disclosed. The silicon nitride sintered body has a low thermal conductivity while high mechanical strength and high thermal shock resistance being maintained.

Abstract: Method of producing a refractory light-weight brick from a mixture of a granular refractory material, a binder, a foaming agent, further addition agents, and water, wherein the mixture is poured as a foamed, aqueous slurry into molds and the set moldings are dried and fired. The mixture contains, by weight, 1-10% hydrated aluminumhydroxychloride, 0.1-3% magnesia (MgO) and 87-97% refractory material. The slurry sets rapidly in the molds.

Abstract: The sol-gel process for forming dense, alumina-base ceramics, the process comprising1. preparing a dispersion of aluminum oxide monohydrate containing a precursor of a modifying additive in the form of a soluble salt;2. gelling the dispersion;3. drying the gel dispersion to form a solid;4. calcining the solid; and5. sintering the calcined solid,is improved by adding to the dispersion at least about 10 weight percent, based on the oxide equivalent of the soluble salt precursor, of at least one densification aid selected from the group consisting of alcohols, glycols and polyether compounds having a vaporization point in excess of the temperature at which the dispersion is dried. This improved process is particularly useful for manufacturing abrasive grains.

Abstract: A ceramic support for the fixation of microorganisms thereto consists of a silico-aluminate having 5-25% magnesia and an average granulometry of 5-300 microns, with the coarsest grains being no more than two times the diameter of the finest grains, and preferably less than 1.5 times the diameter of the smallest grains. This support, which is suitably obtained by calcining a mixture of kaolinic clay and talc or magnesium carbonate and containing no more than 50% cordierite, then grinding and sintering to the desired granulometric distribution, is particularly desirable in the fixing thereto of hybridomas to produce monoclonal antibodies, or biological catalysts.

Abstract: Unfired refractory structural member in the form of a plate for the expendable lining of metallurgical vessels, especially for tundishes used in continuous steel casting, and comprising magnesia sinter and possibly olivine with a grading of 30-45% by weight under 0.09 mm, and 55-70% by weight 0.09 to 4 mm, including 20-40% by weight over 1 mm; cork or granulated ceramic fibers as a pore-forming material; an inorganic binder; and possibly other additives. This refractory structural member has good strength, a small ignition loss, a low content of volatile hydrogen-containing substances, a favorable peeling behavior, and good resistance to slag and molten steel.

Abstract: A method for forming a substrate for electronic applications having a dielectric constant of less than 6 is disclosed. The method comprises admixing crystalline cordierite particles having a size of 0.1--10 microns with a binder and solvent, casting the same into a sheet, drying the cast sheet into a self-supporting green sheet and then heating the green sheet to burn out the binder and to sinter the particles together. A metallization pattern is deposited on the green sheet after the casting but before the heating, the metallization pattern being molybdenum or tungsten. The cordierite has a defined coefficient of thermal expansion. A dielectric substrate for mounting of integrated circuit devices thereon is also disclosed.

Abstract: Molten alkaline earth metal halides are used to convert highly stable oxides into the corresponding anhydrous halides. Usually a third reactant, such as silica, is added in order to bind the basic oxide thus formed. The solid oxide compounds (e.g. silicates) which result are wellknown ceramic phases of a high degree of purity.

Abstract: Bonded aggregate brooder radiant heat panels and, processes for their production, are provided. The panels are made using a workable quick-setting non-toxic non-ammoniacal mixture of magnesium oxide, aluminum oxide, aggregate and mono aluminum phosphate acidic solution. The panels can be made in various forms ranging from low density to load-bearing forms which may be refractory, insulative, heat reflective, light weight, labor and energy conserving, etc.

Abstract: Spray-coating materials having a high heat-resistance and thermal conductivity for the surface protection of materials. The spray-coating material consists of 8-35 wt. % magnesium oxide MgO or calcium oxide CaO, 2-10 wt. % of beryllium oxide BeO and 55-90 wt. % of aluminum oxide Al.sub.2 O.sub.3, zirconium dioxide ZrO.sub.2, silicon dioxide SiO.sub.2, chromic oxide Cr.sub.2 O.sub.3 and titanium dioxide TiO.sub.2. The spray-coating material of the invention can be employed to advantage, for example, in the chemical industry and in metallurgy.

Abstract: A method for producing a cordierite body having no anisotropic property in coefficient of thermal expansion comprises the steps of preparing a raw material containing kaolin mineral and talc as main ingredients, and preformed cordierite particles formed from the raw material, mixing and kneading the raw material together with the preformed cordierite particles into a slurry, forming the slurry into a formed body and firing the formed body.

Abstract: There is disclosed a green moulded product suitable for preparing shaped fired units comprising (a) at least 55% to 99% by weight of non-calcined asbestos tailings, the remainder comprising (b) at least one of (i) a heat decomposable metal salt selected from sodium, potassium, lithium, calcium, barium, magnesium, aluminum and mixtures thereof in an amount of from 1% to 15% by weight, (ii) a natural aluminum silicate in an amount of from 1% to 30% by weight, and (iii) mixtures of (i) and (ii). The properties of fired units are such that they can be used as structural bricks, medium refractory bricks, firebricks, tiles and the like.

Abstract: A process for producing a cordierite ceramic product comprises blending a starting cordierite composition which comprises:(a) a clay formulation having a cordierite composition comprising kaolin, talc and aluminium oxide and/or an aluminium compound which is convertible into aluminium oxide;(b) a glass having a cordierite composition;(c) an organic binder; and,(d) water.

Abstract: Sheathed electrical heating elements containing MgO heat conductive, electrical insulating material having a high degree of calcination together with additives in the form of a clay and fumed silica to increase the electrical resistivity, density and flow properties.

Abstract: A process for the manufacture of industrial cordierite ceramic units containing from 45 to 68% by weight of silica 16 to 37% by weight of magnesia and 12 to 45% by weight of alumina which comprises (a) mixing from 15 to 60% by weight of the non-magnetic fraction of asbestos tailings having a MgO:SiO.sub.2 of from 0.8 to 1.25 with 40 to 85% of a kaolin clay by weight and 0 to 10% of alumina; (b) shaping said mixture in green unit forms; (c) curing said units at room temperature for 24 h then at 110.degree. C. for 24 h; (d) firing said cured units at a temperature of from 1350 1400.degree. C.

Abstract: A method for producing a cordierite body having high crystallinity and exhibiting excellent low thermal expansion property in a specific direction at a relatively low firing temperature comprises the steps of mixing and kneading a batch raw material containing halloysite particles and plate-shaped talc particles, anisostatically forming the batch raw material into a formed body to impart a planar orientation to the plate-shaped talc particles within the batch raw material and drying and firing the formed body.

Abstract: Bonded aggregate structures, processes for their production, improved wall, floor and ceiling panel structures laminated with bonded aggregate and methods for their production are provided. The structures are made using a workable quick-setting non-toxic non-ammoniacal mixture of magnesium oxide, aluminum oxide, aggregate and mono aluminum phosphate acidic solution. The panel structures, especially for building purposes and the like, can be made in various forms ranging from low density to load-bearing forms which may be refractory, insulative, heat reflective, light weight, labor and energy conserving, etc.

Abstract: A dry, lightweight refractory mixture which can be shipped and stored in a dry form, but which becomes plasticized upon the addition of water to yield a moldable, air-setting, insulating refractory composition, the dry refractory mixture including from about 35 to about 70% by weight ceramic fiber; from about 10.5 to about 40% by weight setting agent, preferably a mixture of aluminum phosphate powder and calcined magnesia powder; from about 5 to about 20% by weight of dry, water-soluble, powdered resin binder prepared from urea formaldehyde or melamine formaldehyde, and from about 0.3 to about 2% by weight of dry, water-soluble, non-ionic, powdered organic polymer gelling and cohesion enhancing agent. The dry mixture also preferably includes from about 0.5 to about 2.0% by weight of a dry, water-soluble acidifying agent for catalyzing the air-setting of the plasticized composition.

Abstract: A modified cordierite (2MgO.2Al.sub.2 O.sub.3.5SiO.sub.2) composition in which at least a portion of the silicon dioxide is replaced with germanium oxide. These compositions have low thermal expansion, excellent formability and thermal shock resistance making them especially suitable for the manufacture of mirror substrates to be used at elevated temperatures. By selecting the proportion of germanium oxide according to the intended operating temperature, substantially zero thermal expansion can be achieved between room temperature and the selected operating temperature. Methods of manufacturing the material and of selecting the thermal expansion characteristics are also disclosed.

Abstract: A storable cement product is a dry mixture of magnesium oxide (MgO) and aluminum phosphate, or a product containing MgO and, separated therefrom, an aqueous aluminum phosphate solution, some or all of an inert aggregate component optionally being present in either product. In 45-kg samples, the mortar formed when the MgO, phosphate, water, and aggregate are combined attains an exotherm in the range of about 40.degree.-90.degree. C. after an interval of 10 minutes. The mortar hardens quickly thereafter, and is uniquely suited for patching roads under varying conditions of application and use. The reaction exotherm is controlled by a unique combination of the concentrations of the four critical components, and the surface area and particle size of the MgO.

Abstract: A method for producing a cordierite body having isotropic coefficient of thermal expansion comprises the steps of preparing a batch by mixing and kneading particles of fired talc, alumina supplying substance such as alumina and aluminum hydroxide, and silica supplying substance such as silica and kaoline, anisostatically forming the batch and drying and firing the obtained formed body.

Abstract: Provided by this invention is a slaking-resistant calcia refractory comprising, as a fired mixture, (a) 2% by weight or less of silicon dioxide, (b) aluminum oxide (Al.sub.2 O.sub.3) and magnesium oxide (MgO) of the amount defined in the graph of FIG. 5 as within the region enclosed by the lines connecting point A (2.5 wt % Al.sub.2 O.sub.3 and 0 wt % MgO), point B (1.5 wt % Al.sub.2 O.sub.3 and 1.5 wt % MgO), point C (1.5 wt % Al.sub.2 O.sub.3 and 8.5 wt % MgO) and point D (10 wt % Al.sub.2 O.sub.3 and 0 wt % MgO), (c) 0.9% by weight or less of iron oxide, and (d) a predominant amount of calcium oxide.

Abstract: An electrically conducting cermet comprises a sintered compact of refractory oxide granules such as alumina granules having diameters of from 50 to 800 microns and a conductive network extending through the cermet and provided by a layer of one or more of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt or nickel surrounding the individual oxide granules and constituting a volume fraction of 0.04 to 0.2 of the total cermet, wherein particles of one or more of said metals are dispersed within the oxide granules in a volume fraction of 0.01 to 0.15 of the granules, which granules also contain 0.01 to 0.25 percent by weight of magnesium oxide.

Abstract: A stable aqueous magnesium oxide refractory ramming mix using an alkali metal aluminate as a binder component is disclosed.

Abstract: Substantially non-aqueous, plastic, high magnesium oxide refractory compositions are disclosed. The materials remain fluid over prolonged storage times, providing for easy workability and require no addition of water prior to use.

Abstract: Impervious, unglazed, sintered ceramic products of primarily cordierite crystal phase, exhibiting low coefficients of thermal expansion and having analytical molar composition of about 1.7-2.4 RO . 1.9-2.4 Al.sub.2 O.sub.3 . 4.5-5.2 SiO.sub.2, are formed of mineral batch compositions that are: (a) wholly raw ceramic material wherein RO comprises about 55-95 mole % MnO and 5-45% MgO, or (b) at least about 50 wt.% prereacted cordierite material and the balance thereof raw ceramic material, and wherein RO comprises about 5-40 mole % MnO and 60-95 mole % MgO.