Abstract: An improved alumina reduction cell is disclosed. Vapor barriers, formed from a castable refractory and a silicon carbide mortar protect the bottom and sidewall insulation material of the cell from attack by the corrosive materials contained within the cell.

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: A carbonaceous article, e.g., a carbon or graphite crucible or mold, is provided with an oxidation prohibitive coating comprising a rigid, glassy, ceramic, refractory material containing mullite and silicon carbide or boron carbide or both. The carbonaceous article has a coefficient of thermal expansion which is greater than about 1.5.times.10.sup.-6 inch/inch/.degree.C.

Abstract: An aluminosilicate ceramic product or article and a method of forming the article from as-mined ore. The product is useful as a proppant in gas and oil well fracturing. The ratio, on a calcined basis, of alumina to silica is between approximately 2.2 to 4.0. The amount of iron in the product is controlled as a function of the alumina to silica ratio so as to produce products having less than ten percent (10%) crush loss when subjected to a force of 10,000 psi.

Abstract: A ceramic composed of 1 to 15 percent of glass and 99 to 85 percent of a mixture of particulates is disclosed. The glass, present as a vitreous phase bonding the particulates into a dense, gas impervious structure, contains 45 to 80 percent of SiO.sub.2, 8 to 65 percent of CaO and MgO and not more than 15 percent of Al.sub.2 O.sub.3. The particulates, which are finer than 15 microns in ultimate particle size, include Al.sub.2 O.sub.3 and at least one of ZrO.sub.2, HfO.sub.2 and solid solutions of the two. The ceramics are subject to microcracking, which can be cured by refiring, or prevented by including particulate Y.sub.2 O.sub.3 as a stabilizer.

Abstract: Method and composition for protecting an electrical grounding device having a generally vertically disposed metal tubular electrode buried in the ground. Near the lower end of the tube, slots are provided in the sidewalls through which a special viscous fluid composition is injected into the surrounding soil to fix the tube in place and provide electrical contact with the earth. The composition surrounds and prevents excessive corrosion of buried metallic bodies and particularly those metallic bodies which are intended to provide electrical contact with the earth. The composition surrounding the metallic body contains primarily metallic oxides such as silicon dioxide. The oxidation activity of the metallic component should have a single electrode potential (standard or formal) at 25.degree. C. of from -0.4 to -2.90. The composition may also contain other metallic oxides in admixture with the primary oxide.

Abstract: This invention relates to a method for producing nitride bonded refractory shapes in which the bonding matrix is formed in situ. The method comprises forming a batch including a coarser portion selected from the group calcined and fused aggregates of alumina, aluminosilicate, and magnesium aluminate spinel and a finer portion consisting essentially of finely divided silicon metal and alumina as well as fines of the above mentioned refractory aggregate needed to achieve the desired screen analysis. The silicon metal and alumina react in the nitriding atmosphere to form a low porosity matrix generally comprising silicon oxynitride with corundum distributed therethrough.

Abstract: A mullite containing cementing mix particularly suited for silicon carbide containing shapes is shown that is adapted to be initially activated when mixed with water and set by air drying so that it can subsequently permanently set by firing the mortar in situ. The mullite component is first mixed in a raw batch with ball clay, a chemically active alumina, bentonite, sodium silicate and a borosilicate glass frit and then after this composition is mixed with water and air dried, the cement is fired in place to react certain of the constituents in the mix and sinter the mullite phase in a bonded relation with the surface of the shapes being cemented in place. A refractory furnace liner or the like may thus be fabricated for example wherein the silicon carbide containing shapes forming the liner are held in place with an inert strongly adhering cement having substantially the same thermal expansion properties as the shapes being bonded.

Abstract: Novel transformation toughened ceramic compositions comprising finely divided ZrO.sub.2 -HfO.sub.2 solid solution particles dispersed in a Al.sub.2 O.sub.3 -Cr.sub.2 O.sub.3 (alumina) or 3Al.sub.2 O.sub.3.2SiO.sub.2 -3Cr.sub.2 O.sub.3.2SiO.sub.2 (mullite) solid solution matrix phase. It is found that increased hardness and modulus associated with higher relative Cr.sub.2 O.sub.3 content (e.g. 20 mole %) in the matrix phase and increased fracture toughness associated with higher relative HfO.sub.2 content (e.g. 10 to 20 mole %) in the disperse phase represent viable and improved ceramic compositions. Such transformation toughened ceramic compositions are considered useful in superhot light diesel engine applications, high temperature gas turbines and ultrahigh temperature ceramic heat exchangers.

Abstract: Method for producing a polycrystalline body comprised of from about 50% by weight to about 95% by weight of mullite and from about 5% by weight to about 50% by weight of cordierite, said body having a porosity of less than about 10% by volume.

Abstract: Electroconductive ceramic materials with high density, high mechanical strength, high endurance to repeated current supply and excellent thermal shock resistance can be obtained by mixing 5 to 70 parts by weight of Al.sub.2 O.sub.3 or alumina ceramic materials containing 95% by weight or more of Al.sub.2 O.sub.3 and 30 to 95 parts by weight of at least one electroconductive material selected from of ZrB.sub.2, ZrC, ZrN, ZrSi.sub.2, TaB.sub.2, TaC, TaN, TaSi.sub.2, TiB.sub.2, TiC, TiN, Mo.sub.2 B.sub.5 and MoSi.sub.2 adding a molding binder, molding the mixture and sintering the molded mixture. The electroconductive ceramic is usable for heaters, glow plug heaters, electrical gas ignitors, kerosine gasifying burners, and electrodes or conductors for water processing or dialysis.

Abstract: Method for producing a polycrystalline body comprised of from about 50% by weight to about 95% by weight of crystalline mullite and from about 5% by weight to about 50% by weight of crystalline beta spodumene, said body having a density greater than 85% of its theoretical density.

Abstract: A refractory composition for use in contact with molten aluminum alloys containing a refractory aggregate, a binder and 9Al.sub.2 O.sub.3.2B.sub.2 O.sub.3. The aluminum borate may be of the type produced as a by-product in the production of ferro-boron alloys and known as aluminum boron slag.

Abstract: A refractory composition having a high resistance to corrosion by molten metal chlorides and chlorine gas at elevated temperatures. The composition comprises about 100 parts by weight of a nitride refractory filler, a suitable quantity of a colloidal sol binder and less than about 4 parts by weight of the oxides or hydroxides of magnesium, calcium, chromium and manganese.

Abstract: A ceramic fiber composition for use in contact with molten aluminum alloys is disclosed which is lightweight and porous. The composition contains ceramic fibers, binders and an additive containing 9Al.sub.2 O.sub.3.2B.sub.2 O.sub.3. The additive is preferably aluminum boron slag which is a by-product of the production of ferro-boron.

Abstract: Vibratable, monolithic refractory mixes useful to form linings for receptacles and related apparatus components used to handle or treat molten metal, such as ladles, tundishes, troughs and runners, including novel binders therefor.

Abstract: A low thermal expansion cordierite ceramic is produced by combining cordierite with a zirconium compound and a phosphorus compound and sintering the resultant mixture thereby giving rise to zircon therein.

Abstract: Highly gas-tight rotary cordierite heat regenerator is formed of a honeycomb structural body having a porosity of 20-45% and mainly consisting of cordierite, and open pores of the partition walls defining channels of the honeycomb structural body are sealed with a filler thereto, the difference of thermal expansion between the honeycomb structural body and the filler being less than 0.1% at 800.degree. C. The honeycomb structural body is made by preparing fired segments thereof, sealing the open pores of the partition walls with the filler thereof, bonding the segments with a ceramic bonding material, and firing the bonded segments.

Abstract: This invention is directed to the production of sintered ceramic articles wherein aluminum titanate and mullite constitute the predominant crystal phases and wherein the microstructure thereof evidences grain boundary and intracrystalline microcracking. The articles have base compositions encompassed within the area I, J, K, L, M, I of the drawing to which 0.5-5% Fe.sub.2 O.sub.3 and/or 0.5-5% rare earth metal oxide may be added.

Abstract: What is disclosed is a method of preparing carbon-containing monolithic glassy ceramics from organosilsesquioxanes, metal oxides and metal alkoxides through pyrolysis of their gels. Also disclosed are certain gel compositions used in the method and the glassy ceramics.

Abstract: Flaky .beta.-SiC mainly composed of .beta.-SiC which is obtained from an organic silicon polymer containing the carbon and silicon atoms as the major skeletal component and the method for producing such flaky .beta.-SiC are disclosed. Such .beta.-SiC is especially utilized as the starting material for ceramics having a laminar structure as well as for the refractories. The ceramics and refractories provided with such .beta.-SiC have excellent resistance to thermal shock, to thermal fatigue as well as to oxidation.

Abstract: Refractory compositions based upon alumina or aluminum silicate chemically bound by aluminum phosphate have a shelf life of three months to more than one year where the composition includes both liquid aluminum phosphate and phosphoric acid to form a portion of the aluminum phosphate binder in situ. In accordance with another embodiment of the present invention, increased strength is achieved by including alumina, and an aluminum silicate bearing material, such as clay, in the refractory composition to form the in situ aluminum phosphate bond from the reaction of phosphoric acid and aluminum silicate. The aluminum phosphate should be provided in the composition in an amount of about 5% to about 70% by weight of the bone dry composition and the phosphoric acid should be included in an amount in the range of about 1% to about 10% based on the weight of the bone dry composition to provide the surprisingly new and unexpected shelf life to the refractory composition.

Abstract: Optically translucent theoretically dense body of mullite is produced by pressing an amorphous mixed oxide powder composition of from about 72.5 weight % to about 76.5 weight % Al.sub.2 O.sub.3 /balance SiO.sub.2 into a compact of density of at least 1.0 g/cc, sintering the compact in oxygen or a vacuum of 0.05 torr to 1 torr producing a gas-impermeable compact, hot isostatically pressing the gas-impermeable compact to theoretical density, and with respect to compositions ranging from higher than about 74 wt % Al.sub.2 O.sub.3 /balance SiO.sub.2, annealing the theoretically dense body.

Abstract: A refractory powder for use in a light guide assembly for transmitting a thermal radiation from a melt to a pyrometer through the lining of a metallurgical vessel.The proposed powder has the following composition (by wt. %); aluminum oxide from 40 to 70, silicon dioxide from 29 to 59, and a sintering agent from 0.3 to 2.0. As the sintering agent use is made, in particular, of a boric acid.According to the proposed method the aluminum oxide powder and the silicon dioxide powder are heated to a temperature of from 1200.degree. to 1400.degree. C. and from 900.degree. to 1200.degree. C. respectively, then cooled to a room temperature and mixed with simultaneously adding thereto a sintering agent until a uniform mixture is produced.

Abstract: A dry ramming refractory cement composed principally of coarse dense alumina grains, silicon metal powder, calcined alumina and sodium hexametaphosphate, and optionally one or more materials from the group including silicon carbide, fused white alumina, chromia, periclase, kyanite, graphite and cryolite.

Abstract: Amorphous mixed oxide powder composed of from about 74 weight % to about 76.5 weight % Al.sub.2 O.sub.3 balance SiO.sub.2 is pressed into a compact with a density of at least 1 g/cc, fired in oxygen or vacuum of 0.05 to 1 torr producing a gas-impermeable compact, and sintered in air, argon, helium, nitrogen or mixtures thereof producing an optically translucent theoretically dense body of mullite.

Abstract: Amorphous mixed oxide powder composed of from about 74 weight % to about 76.5 weight % Al.sub.2 O.sub.3 balance SiO.sub.2 is pressed into a compact with a density of at least 1 g/cc and sintered in oxygen producing an optically translucent theoretically dense body of mullite.

Abstract: An amorphous refractory settable at low temperatures comprises a usual refractory material, a metal powder in an amount of 0.5 to 5% by weight based on the whole amount of the refractory and serving as a sintering agent and a phosphate glass powder in an amount of 0.5 to 3% by weight based on the whole amount and serving as a sintering and setting agent. A pitch powder can be further incorporated in the refractory in an amount of 0.1 to 6% by weight based on the whole amount to render the refractory settable more effectively at low temperatures. The refractory is usable in the form of a dry powder without using any water or other liquid for lining troughs and containers for molten metals.

Abstract: Carbonaceous bonded refractory shapes in which the predominant refractory aggregate is andalusite, being characterized by the absence of substantial shrinkage after coking at 2000.degree. F.

Abstract: Flaky .beta.-SiC mainly composed of .beta.-SiC which is obtained from an organic silicon polymer containing the carbon and silicon atoms as the major skeletal component and the method for producing such flaky .beta.-SiC are disclosed. Such .beta.-SiC is especially utilized as the starting material for ceramics having a laminar structure as well as for the refractories. The ceramics and refractories provided with such .beta.-SiC have excellent resistance to thermal shock, to thermal fatigue as well as to oxidation.

Abstract: Mullite ceramic fiber produced by mixing an aluminosilicate fiber having less than 72 weight percent of Al.sub.2 O.sub.3 with high-alumina substances, such as polycrystalline high-alumina fibers having more than 72 weight percent of Al.sub.2 O.sub.3, and heating of the mixture to about 1,300.degree. to 1,450.degree. C., results in a refractory material characterized by lower bulk density, a low degree of contraction, substantial maintenance of original fiber shape, and total or nearly total consumption of free silica, with corresponding reduction in silicic acid.

Abstract: A highly reinforced refractory is disclosed. In accordance with the invention higher reinforcement of refractory shapes such as plunging bells or injection lances is achieved by infiltrating a bed of metal fibers in a mold with an aqueous slurry of a refractory material containing a superplasticizer. Refractory Concrete comprises e.g. calcium aluminate cement, alumina aggregate of 35 mesh or less maximum particle size, sulfonated naphthalene formaldhyde as superplasticizer and greater than 4 volume % metal (steel) fibers.

Abstract: The invention relates to a method of preparing a product containing, as a single crystalline phase, a solid solution or .beta.'-sialon type having the general formula Si.sub.6-Z Al.sub.Z O.sub.Z N.sub.8-Z where Z=1 to 4, which comprises heating in a nitrogen atmosphere, at 1400.degree.-1600.degree. C., agglomerated elements obtained by drying a paste comprising a silico-aluminous material, such as kaolinitic clay, carbon, and a pore-generating agent comprised of fine particles of a ligneous material, such as sawdust or a powder of olive stones.

Abstract: A lightweight, porous, ceramic material is made by mixing a slurry containing a foaming agent until a constant volume of foam is achieved. The foam is then pumped or poured into a mold or form where it sets up into a cellular structure. The formed foam is then cured, dried and heated at elevated temperatures. The slurry used in making the foam is made from ceramic particles, water, foaming agent and bonding materials. The bonding materials function to provide an initial bond as the foam is generated to prevent foam collapse, a low temperature bond after the foam structure is set, cured and dried, and a final bond after heating to elevated temperatures. In a preferred embodiment, the ceramic particles used are alumina.

Abstract: A refractory composition comprising .rho.-alumina as a binder. The refractory composition further includes as a binding assistant at least one selected from the group consisting of a dispersant, fumed silica and glass powder.

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: The invention provides a particulate sealing material for use in preparing hermetic seals between ceramic and cermet members, which material comprises at least 70 wt. % refractory oxide and minor quantities of non-vitreous additive comprising SiO.sub.2, MgO and B.sub.2 O.sub.3. This particulate sealing material is conveniently pressed into the form of a coherent element shaped to suit the particular sealing operation concerned, e.g. the sealing of an open end of a ceramic arc tube to a cermet closure therefor. The invention also provides a method of sealing a ceramic component to a cermet member by interposing said sealing material between the opposed faces of the component and member and applying heat and pressure to sinter the sealing material and achieve a seal between the component and member.

Abstract: SIALON sintered product having the formulaSi.sub.6-z Al.sub.z O.sub.z N.sub.8-z(z is 0 to 4.2) is produced by sintering a molded product of the starting materials for SIALON in the condition of covering the surface of said molded product with a mixed powder of Si.sub.3 N.sub.4 and SiO.sub.2 as main components in nitrogen gas atmosphere.

Abstract: A glass forming compound having in its melted glass phase the formula Si.sub.2 AlO (PO.sub.4).sub.3 or 4 SiO.sub.2.Al.sub.2 O.sub.3.3P.sub.2 O.sub.5 is provided together with grain mixtures for producing refractory thermally insulating bricks adapted for use in the preheating zone of a rotary cement kiln operating in an atmosphere containing alkali chlorides, particularly KCl. The bricks develop a glass layer on the kiln exposed face thereof which resists penetration by alkalis, particularly KCl.