Abstract: A refractory is disclosed which contains integrally sintered magnesia particles forming the skeleton of the refractory and a mineral phase of magnesium orthotitanate (Mg.sub.2 TiO.sub.4) formed between the magnesia particles, thus giving an increased erosion resistance. Preferably, the refractory comprises coarse magnesia particles having an average particle diameter of at least 1 mm or a mixture of coarse magnesia particles having an average particle diameter of at least 1 mm and medium magnesia particles having an average particle diameter of 1 to 0.15 mm and 5 to 50 wt. % of magnesium orthotitanate intervening between the magnesia particles. The refractory not only has an excellent durability in a basic atmosphere, but also has a high strength because of combination of the coarse or medium magnesia particles so that it does not tend to deform and has a high durability against thermal shock.

Abstract: A thermoelectric semiconductor material is disclosed. The material comprises a double oxide which contains antimony and has a trirutile crystal structure.

Abstract: Compositions for refractory materials and methods for providing the compositions are described. A synthetic forsterite-rich refractory sand composition includes a mixture. The mixture includes: a) a carbon bridging agent, the carbon bridging agent being present in the mixture in a proportion of from approximately 5 to approximately 15 percent by weight of the mixture; and b) a synthetic forsterite-rich sand, the synthetic forsterite-rich sand being free-flowing, having a MgO:SiO.sub.2 weight ratio of at least approximately 1.2, a specific gravity of approximately 3 g/cm.sup.3, a void volume of less than approximately 50 percent by volume of the synthetic forsterite-rich sand, and a fusion point of at least approximately 1610.degree. C., wherein i) at least approximately 50 percent by weight of the synthetic forsterite-rich sand is forsterite, and ii) from approximately 3 to approximately 27 percent by weight of the synthetic forsterite-rich sand is maghemite.

Abstract: The present invention pertains to a refractory ceramic mass, consisting of a pure magnesia component A and a component B, which consists of granules of pure magnesia, wherein the magnesia granules of component B have a ceating consisting of a refractory material whose granule size is fine compared with that of the magnesia granules and is chemically extensively inert with respect to the magnesia granule or reacts with the magnesia granule and/or itself consists of a plurality of components that are chemically reactive with one another.

Abstract: Chrome-free bricks which exhibit excellent resistance to corrosion, penetration, and thermal spalling. The bricks are mainly made from a magnesia material and/or a magnesia-alumina spinel material and comprise 1 to 10 wt % titania and 1 to 15 wt % alumina. They may contain 0.5 to 10 wt % iron oxide. Further, they may contain at least one material of the group consisting of 1 to 10 wt % metal powder, 1 to 20 wt % carbon and 1 to 20 wt % one of oxide materials except for iron oxide.

Abstract: The present invention pertains to a refractory brick based on at least one refractory metal oxide in a particle fraction of <8 mm containing 4 to 30 wt. % of a very fine refractory fraction, prepared by firing below a temperature at which the particles of the very fine refractory fraction sinter by recrystallization with grain growth.

Abstract: A ceramic adhesive comprises a ceramic matrix formed from a mixture of a metallic oxide and an alkali silicate in water, and silicon carbide whiskers dispersed within the ceramic matrix. Further, a ceramic adhesive comprises a ceramic matrix formed from a mixture of magnesium oxide in the range of about 50% to about 80% by weight and sodium silicate in water in the range of about 50% to about 20% by weight, and silicon carbide whiskers dispersed within said ceramic matrix, the whiskers being in the range of about 3% to about 25% by weight of the ceramic matrix. A ceramic adhesive of the present invention is particularly useful in mounting and bonding in-cylinder sensors to steel internal engine parts.

Abstract: A substantially non-explosive mixed powder containing finely divided metallic particles suitable for being incorporated in a refractory mixture, intimately mixed together with inert refractory particles. The refractory particles are present in such particle sizes and quantities as ensure that the Minimum Explosible Concentration, as tested in a 20-L vessel with a chemical igniter, is greater than 100 gm/m.sup.3. The inert particles comprise at least 40% of the mixture, and preferably 50% to 80%. The invention also includes a premixed powder, of the metallic and refractory powder, especially as contained in a shipping container in drums or impermeable bags. Due to the presence of the refractory powder, the mixed powder can be shipped without the precautions usually needed for shipping finely divided metal powders.

Abstract: Compounds that satisfy the general formula A.sub.1-Y.sup.4+ A.sub.Y.sup.1+ A.sub.Y.sup.3+ V.sub.2-X E.sub.X O.sub.7 exhibit isotropic NTE behavior above a temperature of about 100.degree. C. Y is from about 0.0 to about 0.4, and more preferably is about 0.2. X is from about 0.6 to about 1.4, and is more preferably about 1. Particularly suitable NTE compounds have X about 1 and Y about 0. A.sup.4+ is selected from the group consisting of Hf, Zr, Zr.sub.a M.sub.b, Hf.sub.a M.sub.b and mixtures thereof wherein a plus b equals one and M is selected from the group consisting of Ti, Ce, Th, U, Mo, W, Pb, Sn, Ge and Si. More preferably, A.sup.4+ is selected from the group consisting of Hf and Zr. A.sup.1+ is selected from the group consisting of the alkali earth metals, A.sup.3+ is selected from the group consisting of the rare earth metals, and E is selected from the group consisting of P and As. The NTE materials may be incorporated into compositions such as epoxy and ceramic compositions.

Abstract: A porous sintered body composed mainly of lanthanum manganite in which a part of lanthanum atoms at A-sites of the lanthanum manganite are substituted by atoms of a metal selected from the group consisting of alkaline earth metals and rare earth metals. The dimensional shrinkage amount of the porous sintered body in heat cycling between room temperature and 1,000.degree. C. is not more than 0.01% per one heat cycle.

Abstract: A pelletizable gunning composition is provided which exhibits excellent flow characteristics, minimal release of dust, and excellent adhesion and resistance to slag. The gunning composition includes high density magnesium oxide as the primary component, and lesser quantities of powdered metal, refractory clay, binder and, preferably, graphite. The dry components are mixed together, and the binder is added and mixed, resulting in a composition that can be pelletized. After pelletizing, the composition can be coated with a dusting material to facilitate pellet flow and prevent pellet agglomeration.

Abstract: A method for improving the properties of ceramic green bodies is provided. In particular, ceramic green bodies having improved green strength are provided. Incorporating certain acid-containing polymers as binders at a level of at least about 1 to about 15, preferably at least about 3 to about 10 percent by weight based on the weight of ceramic particles improves the green strength of the resulting ceramic green bodies.

Abstract: A sintered ceramic-metal composite product has a ceramic matrix of polycrystalline ceramic in which a metal phase is dispersed for adding improved toughness. The metal phase has a higher melting point than the sintering temperature of the ceramic matrix and comprises at least one metal selected from the groups IVa, Va and VIa of the periodic table. The metal phase is dispersed intragranular within the grains of the ceramic matrix to realize nano-order dispersion of the metal phase which is responsible for remarkably improved toughness as well as strength. The ceramic-metal composite product is successfully fabricated by several unique methods utilizing the mixture of the ceramic and metal or metal oxide, hydride or alkoxide.

Abstract: A process for obtaining a synthetic refractory sand for use in steelmaking, said synthetic refractory sand being free-flowing, comprising at least 50% forsterite, having semi-angular and irregularly shaped grains, lenses and flat grains, a specific gravity of approximately 3 g/cm.sup.3, a void volume of less than approximately 50%, a coefficient of thermal expansion of approximately 1.09.times.10.sup.-5 and a fusion point of at least 1610.degree. C. including the steps of: (a) agglomerating a mixture comprising a particulate starting material selected from the group consisting of serpentine-containing asbestos tailings and an enstatite-containing product produced by calcining serpentine-containing asbestos tailings and from 10% to 25%, based on the total weight of mixture, of magnesium oxides or precursors of magnesium oxides with an aqueous binder solution to obtain agglomerates of said mixture; (b) calcining said agglomerates at a temperature of from 1200.degree. C. to 1500.degree. C.

Abstract: Disclosed herein are a refractory material of high-purity electrofused magnesia clinker having good resistance to corrosion by slag, especially the slag with a high iron content, at high temperatures under an oxidative environment, and a burned or unburned refractory brick made of such refractory material of high corrosion resistance, which is superior in corrosion resistance as well as spalling resistance.The refractory material comprises more than 10 wt. % of electrofused magnesia clinker containing 98.0 to 99.8 wt. % of MgO, less than 0.05 wt. % of SiO.sub.2, and 0.1 to 2.0 wt. % of CaO. It may be in the form of burned or unburned or prepared unshaped refractories.

Abstract: A castable refractory composition for use in the production of cast refractory piece, which comprises 1 part by weight of a phosphoric acid solution (H.sub.3 PO.sub.4) having a concentration ranging from 40 to 85% and its primary acidic function partially neutralized by reaction with vermiculite; from 0.1 to 2.5 parts by weight of a mineral such as wollastonite that is refractory and of fibrous structure and may react with one part of the acidic functions of the phosphoric acid that are still free or not neutralized yet; from 0.1 to 2.5 parts by weight of another mineral such as serpentine, MgO or synthetic olivine, containing at least one cation that may react with another part of the acidic functions of the phosphoric acid that are still free or not saturated yet; and from 0.28 to 1.45 parts by weight of water, being provided that the more concentrated is the phosphoric acid solution, the higher is the amount of water to be present in the composition.

Abstract: This invention provides composite ceramic powder comprising matrix ceramic powder and fine particles of ceramic, metal or metal compound which are different from the matrix ceramic powder and dispersed in the matrix ceramic powder. The composite ceramic powder is produced by mixing matrix ceramic powder or its precursor with fine particles to be dispersed therein and then heating the resulting mixture. The composite ceramic powder is also produced by dispersing matrix ceramic particles or precursor thereof in an organic solvent with an organic compound as a dispersoid particle precursor and separating and recovering the organic solvent. The composite ceramic powder is suitable for producing sintered bodies having excellent properties, especially with respect to thermal conductivity, flexural strength and light transmittance, by a conventional ceramic fabrication process.

Abstract: Method for lining a distributor for the continuous casting of metals, in particular steel, comprising preparing material for constituting a wear-resistant refractory lining of the distributor with raw natural dolomite, or raw natural calcite, or a mixture of these two materials, which are chosen with a particle size of between 0 and 5 mm, incorporating in this raw material a binder in proportions of 0.4 to 5% by weight and a mineral or organic plasticizer in proportions of 0.2 to 3% by weight and, after the lining has been placed in position on the distributor in the aqueous form, proceeding to the decarbonation of this lining in the course of its drying and baking, characterized in that the method further comprises incorporating in the material of the lining at least one compound having the property of shrinking at temperatures lower than about 700.degree. C.

Abstract: A process for producing a substantially non-explosive powder containing finely divided metallic particles suitable for being incorporated in a refractory mixture, comprising simultaneously grinding a mixture of pieces of metal with pieces of an inert refractory material to produce a premixture containing finely divided metallic particles and finely divided refractory particles which are intimately mixed together. The refractory particles are present in such particle sizes and quantities as ensure that the Minimum Explosible Concentration, as tested in a 20-L vessel with a chemical igniter, is greater than 100 gm/m.sup.3. The inert particles comprise at least 40% of the mixture, and preferably 50% to 75%. The invention also includes a premixed powder, produced by this process, especially as contained in drums or impermeable bags.

Abstract: Compounds that satisfy the general formula A.sub.1-Y.sup.4+ A.sub.Y.sup.1+ A.sub.Y.sup.3+ V.sub.2-X P.sub.X O.sub.7 exhibit isotropic NTE behavior in the range of normal ambient temperatures. Y is from about 0.0 to about 0.4, and more preferably is about 0.2. X is from about 0.6 to about 1.4, and is more preferably about 1. Particularly suitable NTE compounds have X about 1 and Y about 0. A.sup.4+ is selected from the group consisting of Hf, Zr, Zr.sub.a M.sub.b, Hf.sub.a M.sub.b and mixtures thereof wherein a plus b equals one and M is selected from the group consisting of Ti, Ce, Th, U, Mo, Pt, Pb, Sn, Ge and Si. More preferably, A.sup.4+ is selected from the group consisting of Hf and Zr. A.sup.1+ is selected from the group consisting of the alkali earth metals, and A.sup.3+ is selected from the group consisting of the rare earth metals. Such NTE materials exhibit isotropic negative linear expansion at a temperature below about 100.degree. C.

Abstract: A ladle having a hydrocarbon-free, expendable refractory insulating lining that is chemically compatible with the molten metal to be placed in the ladle.

Abstract: Disclosed is a porous sepiolite having an improved water-resistance and thermal shock resistance obtained by grinding, moisture-conditioning and molding sepiolite, and then calcining said molded sepiolite at a temperature in the range of about 650.degree. C. to about 800.degree. C. Also disclosed is a porous sepiolite having a large specific surface area, wherein the pores having a pore diameter of 50 angstroms or less have a specific surface area in the range of from 40 to 200 m.sup.2 /g and in which no less than 20% of the total surface of the sepiolite is occupied with the pores having a pore diameter of 50 angstroms or less and wherein the pore distribution curve of the sepiolite has a main peak at a pore diameter of no more than 50 angstroms. This sepiolite is obtained by grinding, moisture-conditioning and molding sepiolite, calcining the same at a temperature in the range of about 650.degree. to about 800.degree. C., and then subjecting said calcined sepiolite to an acid treatment.

Abstract: A method of growing mixed crystals having at least two lattice sites each having a different number of adjacent oxygen ions from melts of oxidic multi-component systems, homogeneous mixed crystals being grown such that the cations intended to occupy the first lattice site having the highest number of adjacent oxygen ions and to occupy the second lattice site having the next lowest number of adjacent oxygen ions are chosen such that the ratio of the bond length of the cations in the first lattice site to the bond length of the cations in the second lattice site is in the range from 0.7 to 1.5.

Abstract: The problems associated with the use of chromic acid (CrO.sub.3) binders are substantially overcome by a basic refractory monolith incorporating molybdenum trioxide (molybdic oxide, moO.sub.3) as the binding agent. In accordance with a preferred embodiment, the basic monolith contains about 0.5 wt. % pH modifier, such as sodium carbonate; about 2 wt. % molybdic oxide (MoO.sub.3); about 3 wt. % crude clay; and 75 to 99 wt. % basic refractory aggregate.

Abstract: A self-fluxing binder composition for use in the pelletization of an ore concentrate, especially iron ore concentrates. The composition comprises from 50 to 98% by weight of one or more carrier having a high surface area, and from 2 to 50% by weight of a water soluble organic enhancer. The carrier is selected from the group consisting of natural and synthetic magnesium and/or calcium bearing minerals and preferably consists of synthetic, fibrous-like forsterite. The enhancer is selected amongst the natural polysaccharides, of high viscosity, and more preferably amongst the natural gums of high viscosity such as the guar or xanthan gum and amongst starch and is derivatives. The use of such a self-fluxing binder composition improves the properties of the green and dry pellets and makes them more easy to handle, as compared to those produced with other conventional binders. Moreover, the pellets that are produced with such a binder composition have improved metallurgical properties.

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: Ceramic binder for forming and processing ceramic ware, comprising a sol-gel of a mixture of highly charged metal hydroxy cations and one or more low charged metal hydroxy cations, which are able to form an aqueous sol.

Abstract: High-frequency dielectric ceramics which contains the oxide of a complex perovskite structure as the main component, have a mean crystal gain size of sintered ceramic controlled to within the range of 5 .mu.m to 20 .mu.m and a porosity not exceeding 7% and provides high unloaded Q without requiring long-hour sintering or heat treatment.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron donor material and a carbon donor material. The reactive infiltration typically results in a composite comprising a boron-containing compound, a carbon-containing compound and residual metal, if desired. The mass to be infiltrated may contain one or more inert fillers admixed with the boron donor material and carbon donor material. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing a wide ranging varying volume percentage of ceramic, metal, and porosity.

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: A foamable lining composition to be used as an expendable lining over a permanent refractory lining in a molten metal handling vessel, e.g. a tundish, comprises a particulate refractory filler material, a binder, a foaming agent and water. Calcined magnesite is the preferred refractory filler material and the binder is preferably an acid phosphate or acid sulphate. The water is included in the composition in an amount of from 5 to 15 per cent by weight.

Abstract: Basic monolithic refractories of which the chemical composition consists essentially of, in oxide equivalence, 65%-96% by weight of MgO, 2.6%-20% by weight of ZrO.sub.2, 1.3-10% by weight of SiO.sub.2, 2% or less by weight of CaO, 0.5% or less by weight of Fe.sub.2 O.sub.3 and 1% or less by weight of Al.sub.2 O.sub.3, and with a mineral composition containing periclase as the main component and cubic zirconia and forsterite as sub-components, and with apparent porosity of 7% or less and bulk density of 3.2 g/cm.sup.3 or more.Basic monolithic refractories under this invention possess excellent slaking resistance, slag erosion resistance, slag penetration resistance and spalling resistance. They exhibit an excellent service life, especially as lining material for steel-making furnaces.

Abstract: A fireproof, waterproof, and acidproof binder is characterized by a hardened composition of 10-90% by weight of alkali silicate comprising sodium waterglass, potassium waterglass or a mixture of the same, 1-40% by weight of reactive metal oxide from the group comprising magnesium, titanium, and zinc, preferably magnesium oxide, 1-70% by weight of calcium/magnesium carbonate, preferably dolomite, and, if desired, magnesium silicate, feldspar, a chemically active silica, potassium-sodium-aluminum silicate, sodium carbonate, expanded clay, wood fibers, cement, limestone dust, sand, an organic binder, water or mixtures of the same.

Abstract: The invention relates to a process for lining a distributor for continuous casting of metals, in particular steel, according to which the layer of refractory wear lining is placed in position in aqueous form, characterized in that the said refractory wear lining is composed of raw natural dolomite or raw natural calcite or of a mixture of these two materials, in that its particle size is between 0 and 5 mm, in that a binder, in proportions of 0.5 to 5% by weight, and an inorganic or organic plasticiser, in proportions of 0.2 to 3% by weight, are incorporated in this lining and in that the decarbonization of this lining is carried out after it has been placed in position, during the drying and the calcining thereof.The invention also relates to a distributor lined in this way and to the refractory lining itself.

Abstract: A sinter-reactive lanthanum chromite powder is prepared from the lanthanum chromite precursor LaCr.sub.1-x M.sub.x O.sub.3 (Adsorbate). The powder is crystalline, has the formula LaCr.sub.1-x M.sub.x O.sub.3, where M is magnesium or calcium and x ranges from about 0.03 to 0.3, and sinters to densities higher than about 95% of theoretical density at temperature as low as 1600.degree. C. in inert or reducing atmospheres. Sintering to such high density at temperatures in the vicinity of 1600.degree. C. makes the powder particularly suited for use as interconnect material for solid oxide fuel cells.

Abstract: A lanthanum chromite ceramic powder mixture that consists essentially of 1 mol of LaCr.sub.1-x M.sub.x O.sub.3, where M is a divalent metal selected from the group consisting of magnesium, calcium and mixtures thereof and x ranges from 0.03 to 0.3; y mols of B.sub.2 O.sub.3, where y ranges from 0.005 to 0.04; and z mols of La.sub.2 O.sub.3, where the ratio z/y ranges from 1.1 to 3. The mixture is formed into powder compacts and sintered to near full density at temperatures as low as 1400.degree. C.

Abstract: A magnesia-based sintered body of a homogeneous composition having a porosity lower than 1% and a hydrateability lower than 0.3%, said sintered body having a chemical composition comprising 70 to 99.9% by weight of magnesia and 30 to 0.1% by weight of at least one oxide selected from the group consisting of titanium oxide, aluminum oxide, ferric oxide, phosphorus pentoxide, yttrium oxide, barium oxide, boron oxide, calcium oxide and lithium oxide. The sintered body is obtained by molding a powdery mixture of magnesia and the oxide other than magnesia.

Abstract: Substantially dense, void-free ceramic-metal composites are prepared from components characterized by chemical incompatibility and non-wetting behavior. The composites have a final chemistry similar to the starting chemistry and microstructures characterized by ceamic grains similar in size to the starting powder and the presence of metal phase. A method for producing the composites requires forming a homogeneous mixture of ceramic-metal, heating the mixture to a temperature that approximates but is below the temperature at which the metal begins to flow and pressing the mixture at such pressure that compaction and densification of the mixture occurs and an induced temperature spike occurs that exceeds the flowing temperature of the metal such that the mixture is further compacted and densified. The temperature spike and duration thereof remains below that at which significant reaction between metal and ceramic occurs. The method requires pressures of 60-250 kpsi employed at a rate of 5-250 kpsi/second.

Abstract: An aqueous plastic composition of an inorganic powder which per se has substantially no plasticity which comprises: the inorganic powder and a polysaccharide of natural origin.The molding and sintering of the plastic composition provide a sintered body of high mechanical strength and dimensional accuracy.

Abstract: A process for using nitride-containing aluminum dross residues to produce refractory products. The process involves mixing a dross residue which contains AlN, without prior conversion of the aluminum nitride in the dross to aluminum oxide or hydroxide, with a material comprising a metal oxide or a metal oxide precursor, and calcining the resulting mixture at a temperature suitable to produce a refractory product. During the calcination step, the AlN reacts with other components of the mixture. Since the reaction is exothermic, less heat is required for the calcination step than if a dross residue containing no AlN were used. The AlN can also reduce various contaminants (e.g. Fe.sub.2 O.sub.3, silicon and titanium) present in the metal oxide refractories, and so the invention can be used to produce conventional refractory products of improved purity and appearance. The process enables dross residues to be used for useful purposes rather than being discarded.

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: There is disclosed a silicon nitride based sintered material which contains 0.1% to 20% by volume of zirconium oxide, 0.1% to 14% by volume of zirconium nitride, 3% to 15% by volume of a binder phase of an Mg-Si-O-N or Mg-Si-Zr-O-N system, and balance .beta.-silicon nitride. The sintered material may include an oxide layer of an average thickness of 10 to 1,000 .mu.m in a surface thereof and having a zirconium oxide concentration increasing toward the surface thereof. A process specifically adapted to manufacture the above sintered material is also disclosed.

Abstract: A MgO/SiC composite material in which SiC particles with nano-meter order in size are dispersed within MgO matrix grains can be prepared by hot-pressing the mixture of fine MgO and SiC powders. Addition of SiC particles in the range of 5 volume percent to 50 volume percent to the MgO matrix increased remarkably the fracture strength and the hardness in a nanometer-order structure of the composite.

Abstract: A refractory material containing a synthetic dolomite aggregate having a calcium carbonate coating on the surface thereof and further containing magnesia, a binder, a plasticizer, an organic fiber homogenizer, a bond stabilizer, and a dispersant; and a method of forming a protective refractory surface on the lining of a tundish, steel ladle and the like by spraying, gunning or troweling the surface coated aggregate-containing refractory material thereon are disclosed. This material offers the multiple advantages of improving resistance to slaking, reducing alumina inclusions in the steel, and reducing clogging of the tundish nozzle.

Abstract: A filler material for spiral gaskets has: 36.5 weight percent or more fibrous material, composed of 5 to 20 weight percent ceramic fibers, 13.5 to 25 weight percent sepiolite and 1 to 10 weight percent organic fibers; 59 weight percent or less inorganic powder; and 1 to 10 weight percent organic polymeric binder. The filler material of the present invention may be used as a substitute for conventional asbestos filler material in spiral gaskets and is superior to asbestos filler material in heat resistance.

Abstract: A refractory for casting a basic substance comprises 100 parts by weight of a refractory aggregate having as main ingredients 3 to 40% by weight of zircon and 97 to 60% by weight of magnesia and a suitable amount of a binding agent. Another refractory for casting a basic substance comprises 100 parts by weight of a refractory aggregate having as main ingredients 3 to 40% by weight of zircon and 97 to 60% by weight of magnesia, not more than 7 parts by weight of metallic fibers, and a suitable amount of a binding agent. The refractories for casting a basic substance are used for ladles, tundishes, vacuum degasing furnaces, mixers, and the like.

Abstract: A process for producing a high density ceramic of perovskite represented by the formula:ABO.sub.

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: A mold forming material contains 1-20% by weight of spodumene. Spodumene is a lithium mineral whose theoretical composition formula is Li.sub.2 O Al.sub.2 O.sub.3 4SiO.sub.2. If casting is performed using a mold forming material containing spodumene, a casting which is satisfactory in appearance and accuracy is obtained.

Abstract: Transparent ceramic armor consisting of a light weight composite formed by tilizing a face plate of transparent aluminum oxide or transparent magnesium oxide with a back-up plate of transparent plastic and the two plates bonded together with a transparent adhesive. This composite on test affords complete ballistic protection against 0.30 AP M2 projectiles at 0.degree. obliquity with a muzzle velocity of 2770 ft. per sec.