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 ceramic composition which includes Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 or the oxide precursors thereof, in admixture with barium copper oxide of the formula BaCuO.sub.2 as a sinter aid therefor. The compositions do not contain any free lead oxide and have high dielectric constants, e.g. above 8000, and low loss factors, e.g. below 3%.

Abstract: The invention encompasses a method for manufacturing a high density indium oxide/tin oxide (ITO) sintered body, as well as the ITO sintered body itself. The method produces an ITO sintered body of high homogeneity for use as a sputtering target in manufacturing processes where thin, transparent and electrically conductive ITO layers are deposited over transparent substrates. The method comprises the steps of preparing a slurry whose solid constituents consist of a finely divided mixture of between 99 and 50 weight percent of In.sub.2 O.sub.3 and 1 to 50 weight percent of SnO.sub.2, and between about 0.05 through 0.25 percent of a sintering agent formed from an oxide of, only one of the group consisting of aluminum, magnesium, yttrium, and silicon; forming the resulting slurry into a green body having a density of between about 4.0 and 4.8 gm/c.sup.3 and heating the green body to a sintering temperature of between about 1500 and 1600 C.

Abstract: A novel ceramic ferroelectric material having a low dielectric constant, extremely low loss and high tunability. The material is a composite comprising Barium Strontium Titanate (BSTO) and a ceramic material having a low dielectric constant. The preferred composite is represented by Ba.sub.1-x Sr.sub.x TiO.sub.3 --MgO, wherein x is greater than 0.00, but less than or equal to 0.75, and wherein the percent weight ratio between Ba.sub.1-x Sr.sub.x TiO.sub.3 and MgO ranges from approximately 99%-40% and 1%-60%, respectively. The novel materials possess superior electronic properties; and they may be employed in various antenna systems at both microwave and millimeter wave range frequencies.

Abstract: A refractory mix and resultant shapes formed by burning the mix, the mix comprising a magnesia-alumina spinel grain containing at least 27% MgO by weight, a fused magnesite grain, and up to 10% by weight alumina, it being possible to substitute a sintered magnesite grain for up to 50% by weight of the fused magnesite grain.

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 nonmagnetic oxide substrate material has a composition of 15 to 60 mol % of NiO, 10 to 70 mol % of CoO, 10 to 40 mol % of TiO.sub.2, and 0.5 to 25 mol % of CaO and is formed of very minute crystal grains. Preferably MgO or ZrO.sub.2 is used as an additive to the material to present a total composition containing the additive of 0.5 to 3 wt % per 100 parts by weight of the nonmagnetic oxide substrate material. Preferably, the substrate material is formulated to have a thermal expansion coefficient falling in the range of from 100 to 140 X 10.sup.-7 /.degree.C. A magnetic head using this substrate material reduces the loss in surface smoothness due to the relative slide with the magnetic tape.

Abstract: The present invention relates to a refractory for casting process composed mainly of 0.3 to 10 wt % light burned magnesia, 3 to 30 wt % micro fine calcined alumina, and the remainder of either sintered alumina, fused alumina and MgO-Al.sub.2 O.sub.3 spinel or sintered alumina and MgO-Al.sub.2 O.sub.3 spinel or fused alumina and MgO-Al.sub.2 O.sub.3 spinel.

Abstract: A refractory adhesive and filler paste composition is described which can be extruded, trowelled or parged onto a refractory surface. The composition can be used to adhesively secure shaped refractory articles together or used as a filler. The composition contains refractory grain particles having critical size limitations and a non-aqueous binder system which includes an unsaturated drying oil such as tung or linseed oil and an organic solvent such as naphtha. The composition may be premixed and packaged in a caulking gun cartridge and applied by extrusion.

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: A method for the synthesis of mixed metal oxide crystalline powders comprises the steps of preparing a raw material mixture containing at least two different metal cations; adding a template material to the mixture and blending it therewith; initiating formation of a mixed metal oxide by calcination of the mixture and the template material, whereby particles of the mixed metal oxides are formed; and thereafter recovering the mixed metal oxide particles. Mixed metal oxide crystalline powders comprise a template material; and metal oxides which form pigment classes of material containing the template material, the pigment classes being selected from the group consisting of borate, garnet, olivine, phenacite, phosphate, priderite, pyrochlore, sphene, spinel and zircon, as well as perovskite crystal classes of material containing the template, all of which have a uniform particle morphology and particle size ranging between about 0.2 to 100.mu. with minimal comminution.

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: High purity fused grain and refractory compositions that contain a high purity fused grain made up of 35 to 85 wt. % chromia, 5 to 55 wt. % alumina, and 5 to 45 wt. % magnesia. Burned refractory brick having such a chemistry was found to unexpectedly possess superior resistance to AOD and electric furnace slags.

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 high alumina ceramic composition has controlled small amounts of MgO and CaO. When refractories made from the composition are fired, the alumina and MgO react to form spinel. The CaO promotes such reaction while minimizing undesirable expansion, and results in a refractory having significantly improved hot strength and other desirable physical properties.

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 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 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: This invention relates to processes for preparing ceramic articles which are especially suited for electronic applications. The process involves taking a shaped article which has been formed from a magnesium exchanged zeolite powder, the zeolite selected from the group consisting of philipsite, harmotome, gismondine, zeolite B, zeolite ZK-19 and zeolite W, and sintering it at a temperature of about 1,000.degree. C. to 1,350.degree. C. for about 1 to about 6 hours. The magnesium exchanged zeolite has a SiO.sub.2 /Al.sub.2 O.sub.3 ratio of about 2.3 to about 2.8 and a sodium content less than 0.5 weight percent. The ceramic article that is formed has a substantially crystalline cordierite phase and has a density of at least 90% of its theoretical density. A preferred process involves calcining the magnesium exchanged zeolite powder at a temperature of about 600.degree.-800.degree. C. to collapse the zeolite framework and give upon sintering a cordierite ceramic article which is substantially crack free.

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: Sprayable aqueous insulating liner compositions for metal casting vessels such as permanent refractory lined tundishes are disclosed that contain a water insoluble and hydration resistant particulate refractory grain containing MgO, organic binder and fibers, with the composition being substantially free of water soluble alkali and alkaline earth metal oxides that would migrate during drying with the water to degrade the permanent refractory lining.

Abstract: A cladding for a molybdenum body such as a molybdenum tube for protecting the molybdenum from corrosive high temperature environments. The cladding contains oxides of molybdenum, aluminum, silicon and alkali metals in about the following percentages by weight of the total metal content: molybdenum 18-40 percent; aluminum 10-25 percent; silicon 25-50 percent; and, alkali metals 8-12 percent. The cladding may be formed by bringing the molybdenum body into contact in the presence of oxygen, with a refractory containing oxides of aluminum, silicon and alkali metals at a temperature greater than 400.degree. C.

Abstract: A process is described for making shaped aggregates by mixing the material to be shaped with an aluminum solution and magnesium oxide. The magnesium oxide provides a delayed but strong gelating action to give time for ramming or casting the aggregate into a viable shape.

Abstract: A moldable composiion comprising a mixture of magnesia, alumina, and silicon carbide powders or agglomerates thereof, the powders having an overall average size of at most 5.0 micrometers, preferably an average size in the range of 0.2 to 2.0 micrometers, optionally a polymeric binder, optionally a fluxing agent, and optionally a plasticizer or lubricant which exhibits litle or no controlled dimensional stability upon being fired to a cordierite ceramic material in a novel process. The process involves incorporation of silicon carbide powder into the moldable composition and the reaction of this silicon carbide upon firing to produce silicon dioxide. The cordierite ceramic material is useful where the dimensions of a shaped or molded part must be preserved after firing, as, for example, in the preparation of dental articles or as a mold for casting metals.

Abstract: A lightweight magnesia clinker containing magnesium oxide in an amount of more than 85 wt. % and having an apparent porosity of more than 40 vol. % and a bulk specific gravity of less than 2.0 g/cm.sup.3 is disclosed. In the lightweight magnesia clinker, the amount of magnesia clinker particles having a particle diameter of smaller than 3 mm is more than 90 wt. % of the amount of all magnesia clinker particles, and the amount of pores formed in the magnesia clicker particles having a pore size of smaller than 50 .mu.m is more than 90 vol. % of the amount of all pores. A process for the preparation of said lightweight magnesia clinker is also disclosed.

Abstract: Disclosed are a magnesia-calcium oxide refractory product comprising (i) about 100 parts by weight of a refractory aggregate consisting essentially of about 20 to about 95% by weight of MgO and about 80 to about 5% by weight of CaO and (ii) about 0.5 to about 5 parts by weight of aragonite-type calcium carbonate, and a process for preparing the same.

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: A high-temperature resistant blast pipe is primarily intended for delivering gas, such as oxygen, and, when appropriate, solid material to metallurgical processes, and incorporates a layer of refractory material comprising a refractory mixture of solid particles and an alkali-silicate based binder.The blast pipe is characterized in particular in that the major constituent of the binder is of the type polymerized alkali silicate.

Abstract: A ceramic core for use in the investment casting of metals includes, prior to sintering, about 80 w/o to about 86 w/o of a ceramic filler material and about 14 w/o to about 20 w/o of a binder material. The ceramic filler material includes about 66 w/o to about 95 w/o Al.sub.2 O.sub.3 particles, about 1 w/o to about 20 w/o Y.sub.2 O.sub.3 particles, about 1 w/o to about 5 w/o of a grain growth inhibiting agent, and the balance a carbon-bearing fugitive filler material. Subsequent to sintering, the ceramic core has a microstructure characterized by the presence of substantially unreacted Al.sub.2 O.sub.3 particles having a polycrystalline composition consisting essentially of 3Y.sub.2 O.sub.3.5Al.sub.2 O.sub.3 on the surfaces of the Al.sub.2 O.sub.3 particles.

Abstract: A low temperature sintering ceramic material, having low temperature sinterability and excellent thermal conductivity, is particularly suitable for use in making an IC substrate of a ceramic printed plate board. This low temperature sintering ceramic material has two composition types. One is a binary composition type ceramic material consisting essentially of MgO and B.sub.2 O.sub.3, and the other is a ternary composition type ceramic material composed of principal components consisting of MgO and B.sub.2 O.sub.3 and assisting components consisting of one or more selected from Li.sub.2 O, Na.sub.2 O, K.sub.2 O, a fluoride of an alkali metal and a fluoride of an alkaline earth metal. After sintering, MgO and B.sub.2 O.sub.3 are respectively contained at 50 to 90 mol% and 10 to 50 mol% on 100 mol% of the total amount of MgO and B.sub.2 O.sub.3.

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: A cement for vessels for containing molten alloys of aluminum with metals selected from the group consisting of lithium, magnesium, zinc and copper is shown that forms a hard sintered crust for containing the molten alloy in the vessel with a backing of granular cement for controlling thermal stress while also providing a vitrifying flux means in the cement mix for effecting a sealing of any cracks that may form in the crust by reacting with any hot alloy flowing through such a crack to contain the leak as a metal spur.

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: The invention relates to a refractory brick on the basis of sintered magnesium oxide and MgO.Al.sub.2 O.sub.3 spinel and possibly up to three percent by weight of customary impurities. Such customary impurities are primarily CaO, Fe.sub.2 O.sub.3 and SiO.sub.2, which are included as impurities in the MgO used in the production of the spinel. The refractory brick according to the invention is characterized by the fact that it has a refractoriness under load of more than 1740.degree. C. and a compression settling of -3 to -5% at 1400.degree. C. after 24 hours under a load of 0.2N/mm.sup.2. The refractory brick according to the invention exhibits the advantage that as a result of the combination of its characteristics of gas permeability, pore volume, refractoriness under load and compression settling, it is particularly well suited for use in rotary hearth furnaces for the cement industry.

Abstract: Novel preheatable molded refractory insulating liners and methods of use thereof for lining vessels, such as hot tops, ladles, tundishes, troughs, and pipes, etc., which serve to transfer molten metals, such as ferrous alloys, are disclosed. The new and vastly improved preheatable liners are suitable for developing effectively the required hot strength needed for casting molten metals at both vessel preheat temperatures and casting temperatures. The unique preheatable liners additionally possess the needed hot strength during the range of casting temperatures as are experienced in the metal making industry.

Abstract: A medium weight abrasion-resistant castable for use as a refractory lining having a bulk density of no greater than 130 lbs/cu ft, and abrasion loss of no greater than about 25 cc and a thermal conductivity of no greater than 5.5 BTU/hr/ft.sup.2 /in/.degree.F. includes a coarse aggregate of cordierite. The composition also includes an intermediate sized aggregate of calcined kaolin or calcined flint and a finer sized aggregate of calcined kaolin or calcined flint, fly ash cenospheres, clay, fume silica, and cement.

Abstract: Magnesium oxide ceramic bodies may be strengthened by inclusion of zirconium oxide particles, and may be further sintered to a density approaching theoretical density by conventional sintering techniques by inclusion of sintering aids, such as manganese oxide and iron oxide.

Abstract: A silicon nitride cutting tool primarily for cutting cast iron comprises a granular phase consisting essentially of silicon nitride and an intergranular amorphous phase consisting essentially of magnesium oxide, yttrium oxide and silicon oxide wherein the components are present in specified amounts and ratios.

Abstract: Ceramic materials comprising steatite or forsterite which are highly dense in nature may be prepared by admixing a hydrolyzed alcoholic solution of a silicon alkoxide with a solution prepared by adding an organomagnesium compound to an alcohol at gelation conditions. Following the formation of the gel, it is then dried at an elevated temperature of from about 300.degree. to about 500.degree. C. to remove volatile compounds as well as to decompose any remaining organic compounds and thereafter the powder is pressed into a desired shape. The formed shape is then sintered at a temperature in the range of from about 850.degree. to about 950.degree. C. to form a densified ceramic.

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: 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: There is disclosed a material for hot or plasma spraying, especially a material based on oxide ceramics, and a process for the production thereof. The composition of the invention is a mixture of powdered oxides containing at least two fundamental oxides with high melting point, and at least one glass-forming oxide the melting point of which is lower. The invention also includes a process for the production of such composition by the melting and agglomeration of individual components in the oxidizing medium of a plasma stream, including the special treatment of the starting components.

Abstract: Zirconia ZrO.sub.2, ceria CeO.sub.2 or thoria ThO.sub.2 may be rendered ionically conductive; a typical composition is ZrO.sub.2 +12 mol % CaO.This is sintered in the solid state as a 40 nm powder using as a sintering additive 0.1 mol % MgO at 1450 C. for 4 hours; a density 98% of the theoretical is achieved.For other fluorite oxide compositions, MgO is also useful as a sintering additive but in different proportions.

Abstract: Gunning mixes and other magnesia-based refractory compositions are disclosed which include up about to 10% by weight sulfamic acid as a binder. Sulfamic acid reacts readily with periclase grain and, when employed with boric acid and ceramic sintering aids forms an excellent binder system.

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

Abstract: The invention relates to low-expansion ceramics, the chemical composition of which consists of 1.2 to 20% by weight of magnesia (MgO), 6.5 to 68% by weight of alumina (Al.sub.2 O.sub.3), 19 to 80% by weight of titanium in terms of titanium oxide (TiO.sub.2), 1 to 20% by weight of silica (SiO.sub.2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe.sub.2 O.sub.3); the major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-silicon oxide-iron oxide; the ceramics have a coefficient of thermal expansion of not more than 20.times.10.sup.-7 (1/.degree.C.) in a temperature range of 25.degree. C. to 800.degree. C., a four-point flexural strength of not smaller than 50 kg/cm.sup.2 at room temperature, and a melting point of not lower than 1,500.degree. C.

Abstract: Sprayable aqueous insulating liner compositions for metal casting vessels such as permanent refractory lined tundishes are disclosed that contain a water insoluble and hydration resistant particulate refractory grain containing MgO, organic binder and fibers, with the composition being substantially free of water soluble alkali and alkaline earth metal oxides that would migrate during drying with the water to degrade the permanent refractory lining.