Abstract: A composite comprised of a sintered matrix of spinel ferrite and a non-exposed continuous phase of elemental silver or Ag-Pd alloy ranging to 25 atomic % Pd is produced by co-firing a laminated structure of ferrite powder-containing tapes containing non-exposed metallization-forming material. The composite can be formed into a composite product which contains a continuous silver or Ag-Pd alloy phase with two end portions wherein only the end portions are exposed.

Abstract: Ceramic molding or casting powders, particularly nitride, oxide and carbide powders, that have substantial internal surface and volume produce improved dispersions after being coated with a cover material, such as polyethylene glycol, that reduces the specific surface area of the powder by at least about 10% and reduces the amount of penentration of the binder used for dispersion into the internal volume of the powder. The viscosity of dispersions of such coated powders, or of conventional uncoated ceramic powders, can be further reduced by treatment of the powders with organotitanate, organozirconate, or organosilane coupling agents that are chosen to interact favorably with the specific powders and binders used.

Abstract: A method for fabricating a high-temperature ceramic superconductor having a Y-Ba-Cu-O or other copper-oxide composition of comparable properties so as to render the ceramic porous to define interlaced diffusion channels throughout the entire body of the ceramic. As a consequence, oxygen, an essential component thereof, will in the course of firing the ceramic, diffuse throughout the interior of the body and thereby interact and become integrated with the crystal structure of the ceramic to form a superconductor having superior properties. The resultant porous ceramic body may be used as a superconductive device, or it may be ground into particles and dispersed as a filler in a binder acting as a plastic agent that can be extruded, molded, or otherwise shaped to create a Meisner-effect shield, a cylindrical superconductive bearing or other superconductive structure.

Abstract: A method and process for producing a yttrium oxide metal casting refractory composition is disclosed. Powdered Y.sub.2 O.sub.3 is combined with a sintering agent (preferably V.sub.2 O.sub.5) and an organic binder. The mixture is sintered and ground to produce a stable Y.sub.2 O.sub.3 flour. The flour is added to another binder having specific SiO.sub.2, hydrolysis and viscosity levels in order to produce a slurry. Slurries prepared in accordance with the invention avoid problems traditionally associated with Y.sub.2 O.sub.3 hydration and/or carbonation, and have long storage lives. In addition, the material costs associated with the slurries are low in comparison with products using fused Y.sub.2 O.sub.3. The Y.sub.2 O.sub.3 slurries may also find application as solid preformed cores formed by any conventional injection molding, transfer molding, or slurry casting process.

Abstract: A polycrystalline Y-Ba-Cu-O superconductor doped with sufficient .sup.235 U and/or .sup.239 Pu atoms is irradiated with thermal neutrons to produce from about 2.5.times.10.sup.14 to about 50.times.10.sup.14 fission events per cubic centimeter of superconductor.

Abstract: The specification discloses forming ceramic films, and especially high temperature superconductor films, by dissolving ceramic precursor metal iodides in organic solvents, applying them to a substrate, evaporating the solvent and pyrolyzing and annealing the resulting ceramic precursor metal iodide films.

Abstract: A ferrite-ceramic composite powder consisting of fine particles of a ceramic material having a ferrite coating firmly bonded to the surface thereof is molten at high temperature and then cooled to produce a material in the form of a solid solution in which the ferrite component and the ceramic component are substantially homogeneously mixed together. Also, the ferrite-ceramic composite powder is mixed with fine particles of a second ceramic material and/or particles of a metal, and the mixture is baked to produce a sintered material.

Abstract: Complex metal oxides are formed by calcining in molecular oxygen such as air at least one bimetallic complex of the formula A[BY] wherein A and B are metals and Y is a ligand associated with B. The bimetallic complexes are precipitated from aqueous solution by a transposition reaction of AX and M[BY] wherein X is a disassociable anion and M is a cationic species. The bimetallic complexes are useful in forming pure complex metal oxide fibers by a process of either dispersing the complex metal oxide or bimetallic precursors in a spinning composition of fluid organic polymer or by imbibing a polymeric fiber with species AX and precipitating out the bimetallic complex by treating the imbibed fiber with a compound containing the BY complex. The process is also useful in forming superconductive complex metal oxides.

Abstract: A ceramic article made from a mixture comprising (on a dry weight basis) magnesium oxide (MgO) in an amount up to 2% by weight, a defined rare earth oxide in amount up to 10% by weight, balance beryllium oxide, and trace elements, the defined rare earth oxide being zirconium oxide (ZrO.sub.2), hafnium oxide (HfO.sub.2), cerium oxide (Ce.sub.2 O.sub.3), yttrium oxide (Y.sub.2 O.sub.3), ytterbium oxide (Yb.sub.2 O.sub.3) or thorium oxide (ThO.sub.2). Such ceramic articles have much improved properties in particular higher densities than attainable hitherto and better crossbreak strength and surface smoothness as fired. The ceramic compositions can also be admixed with supplementary ceramic materials such as silicon carbide to produce microwave absorbing materials.

Abstract: Complex metal oxides are formed by calcining in molecular oxygen such as air at least one bimetallic complex of the formula A[BY] wherein A and B are metals and Y is a ligand associated with B. The bimetallic complexes are precipitated from aqueous solution by a transposition reaction of AX and M[BY] wherein X is a disassociable anion and M is a cationic species. The bimetallic complexes are useful in forming pure complex metal oxide fibers by a process of either dispersing the complex metal oxide or bimetallic precursors in a spinning composition of fluid organic polymer or by imbibing a polymeric fiber with species AX and precipitating out the bimetallic complex by treating the imbibed fiber with a compound containing the BY complex. The process is also useful in forming superconductive complex metal oxides.

Abstract: Refractory ceramics are provided which comprise at least about 70 mole percent yttrium oxide and from about 5 to 30 mole percent aluminum oxide. The ceramics are particularly resistant to attack by molten rare earth alloys and are superior refractories for use with molten neodymium-iron alloys in the manufacture of permanent magnets.

Abstract: A sintered body of indium tin oxide is fabricated by forming a finely divided mixture of indium oxide, tin oxide, aluminum oxide and silicon dioxide, compacting the mixture, and heating the mixture to a sintering temperature.

Abstract: A process for preparing compound metal oxides, superconductive compound oxides, is disclosed. The process comprises preparing an aqueous solution containing a predetermined content ratio of chloride, nitrate or acetate of a rare earth metal, an alkaline earth metal and copper, said content ration corresponding to the composition of the object compound metal oxide, adjusting the pH of the solution to 1.5-2.0, adding oxalic acid in an amount such that the concentration of the residual oxalic acid becomes 0.05 M/l-0.1 M/l, collecting the thus formed precipitate and firing it.

Abstract: Slurries or suspensions for forming sintered ceramic or metallic articles are described as having a high volume fraction of sinterable particles, at least 55% by volume. while the slurries maintain a pourable viscosity, such as not more that 2000 cPs at 100 s.sup.-1 ; the slurries can be dilatant and/or pseudoplastic. The slurries are prepared by using specific families of dispersants; namely acrylic acid-based polymeric polyelectrolytes, polyethylene imine-based polyelectrolytes, and coupling agents from the subfamilies of oxy-silane esters and phosphate esters. Fabrication of the compositions includes milling under high energy and the addition of at least a portion of the particles in a step-wise manner.

Abstract: Superconducting compositions of the general formula A.sub.n Q.sub.m Cu.sub.3 O.sub.y are prepared by wet mixing a combination organic acid salts, inorganic acid salts and oxides of A, Q and Cu, wherein at least one salt is an organic acid salt, drying the mixed salts, and then heating the resultant mixed salts to a temperature between 500.degree. and 950.degree. C. The temperature is maintained for a time sufficient to form a substantially orthorhombic superconducting composition. The method achieves good results with only one heating step. The presence of at least one organic salt causes carbonate and nitrate salts of A, Q and Cu to convert to oxides at temperatures between 300.degree. and 400.degree. C. With lower processing temperatures, semiconductor materials and superconducting materials can be processed together.

Abstract: Compositions having the nominal formulaTl.sub.e Pb.sub.a Ca.sub.b Sr.sub.c Cu.sub.d O.sub.xwhereina is from about 1/10 to 3/2,b is from about 1 to 4,c is from about 1 to 3d is from about 1 to 5e is from about 3/10 to 1x=(a+b+c+d+e+y)wherey is from about 1/2 to 3,are superconducting. Processes for manufacturing such compositions and for using them are disclosed.

Abstract: A process for preparing compound metal oxides, a superconductive compound oxides for instance, is disclosed. The process comprises preparing an aqueous solution containing a predetermined content ratio of chloride, nitrate or acetate of a rare earth metal, an alkaline earth metal and copper, slightly basifying the solution to form hydroxides of the rare earth metal and copper and then introducing carbon dioxide to form carbonate of the alkaline earth metal, collecting the thus formed mixed precipitate of hydroxides and carbonate and firing it.

Abstract: Methods of producing ABO.sub.3 compounds in which A represents a first metal ion and B represents a second metal ion from mixed metal coordination complexes are disclosed. The methods involve reacting compounds serving as a source of the B metal ion with a substituted aromatic compound, in solution, and thereafter reacting the metal coordination complex formed with a compound serving as a source of the A metal, in solution. An example is the reaction of titanium tetraisopropoxide with catechol to form a titanium catecholate coordination complex which is thereafter reacted with barium hydroxide octahydrate to form a pentamethanol barium triscatecholatotitanate mixed metal coordination complex which can be calcined at elevated temperatures to produce the ABO.sub.3 compound, barium titanate (BaTiO.sub.3), which is known to have outstanding dielectric, ferroelectric and piezoelectric properties. Portions of the A and/or B ions can be substituted with other metals.

Abstract: Novel superconductive Pb-substituted oxides are disclosed. The oxides all have layered perovskite-like crystal structure, and manifest superconductivity (R=o) above about 77K. The materials are described by the nominal formula X.sub.2+x M.sub.3-x Cu.sub.2 O.sub.8.+-..delta., where X is Bi and Pb, M is Sr and Ca, 0.ltoreq..times..ltoreq.0.3, 0.ltoreq..delta..ltoreq.0.5, the Pb/Bi ratio is between about 0.2 and about 0.5, and the Sr/Ca ratio is between 0.5 and 2.

Abstract: A process for the preparation of copper oxide superconductors which comprises (1) mixing and grinding yttrium nitrate hydrate, copper nitride, and an oxidizing agent such as barium peroxide in a suitable solvent; (2) forming a paste thereof; (3) applying the paste to a substrate; (4) heating the substrate with the paste thereon; and (5) therafter cooling. The process yields copper oxide superconducting compounds in a purity of at least 80 percent.

Abstract: A process for the preparation of copper oxide superconductors which comprises (1) mixing copper nitride, an oxidizing agent such as barium peroxide, and yttrium oxide; (2) forming pellets of the aforementioned mixture; (3) heating the pellets; and (4) thereafter cooling the pellets. The process yields copper oxide superconducting compounds in a purity of from about 60 to over 95 percent.

Abstract: The present invention is directed to a method of producing metal oxides which are useful as high temperature superconductors. The method comprises the steps of:(a) mixing generally stoichiometric amounts of metal compounds with an alkali metal metal hydroxide, thereby forming a mixture;(b) heating the mixture to drive off water; and(c) filtering the mixture to remove the alkali metal ions.

Abstract: Rare earth oxysulfide ceramic material prepared by covering the material with a foil of a metal selected from the group consisting of molybdenum, tungsten, platinum, and rhenium, sealing it into an airtight vessel of tantalum or niobium, and then subjecting it to a hot isostatic press process.

Abstract: A process for the production of a refractory boride or silicide which comprises producing an oxygen-containing polymeric product by reacting a compound of the metallic or non-metallic element having two or more groups reactive with hydroxyl groups and a compound of boron or silicon having two or more groups reactive with hydroxyl groups with an organic compound having two or more hydroxyl groups and heating the polymeric product in an inert atmosphere to pyrolyse the polymeric product and produce a refractory boride or silicide of the metallic or non-metallic element.

Abstract: There is disclosed an improved process for preparing a superconducting composition having the formula MBa.sub.2 Cu.sub.3 O.sub.x wherein M is selected from the group consisiting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0; said composition having a superconducting transition temperature of about 90 K.; said process consisiting essentially of mixing ba(NO.sub.3).sub.2, M.sub.2 O.sub.3 and CuO in an atomic ratio of M:Ba:Cu of about 1:2:3 to form a precursor powder and heating the precursor powder in an oxygen-containing atmoshpere at a temperature from about 875.degree. C. to about 950.degree. C. for a time sufficient to form MBa.sub.2 Cu.sub.3 O.sub.y, where y is from about 6.0 to about 6.4; and maintaining the Mba.sub.2 Cu.sub.3 O.sub.y in an oxygen-containing atmosphere while cooling for a time sufficient to obtain the desired product.

Abstract: Superior homogeneity in ceramic materials is achieved by forming an aqueous solution of trichloroacetates of certain metals, heating the solution to decompose the trichloroacetates to form carbonate precipitates, and recovering the carbonate precipitates. The latter can be calcined to form superconductors. For example, oxides, or carbonates of Y, Ba, and Cu are dissolved in aqueous trichloroacetic acid and the solution is heated to decompose trichloroacetate ions and to form mixed carbonates, which precipitate. The precipitate is recovered and calcined to form a superconducting material.

Abstract: A high density, shock resistant ceramic comprising from 1 to about 4 mols of a dense spinel ceramic matrix having dispersed therein, 1.5 to 1, respectively, of a metal oxide derived from a decomposable salt of said metal and having a thermal expansion characteristic different from said dense spinel ceramic matrix and at the decomposition temperature a volume less than that exhibited by its salt form and a process for preparing same.

Abstract: Ultra-fine spherical particles of a metal oxide having an average particle diameter of 40 nm or smaller can be prepared by a method in which a vaporizable metal compound is vaporized and decomposed under heating to give ultra-fine particles of a metal oxide followed by immediate cooling down to a temperature at which coalescence of the fine particles are prevented from coalescence. The fine particles have characteristics such as an excellent power of ultraviolet scattering.

Abstract: A superconducting mixed valence copper oxide, having a formula of the type:(La.sub.2-x (Y.sub.x" Bi.sub.1-x").sub.x' Sr.sub.x-x').sub.1-e CuO.sub.4-y,where:0.ltoreq.x<0.30.ltoreq.x'.ltoreq.0.2 with x'<x0.ltoreq.x".ltoreq.10<y.ltoreq.0.10.ltoreq.e.ltoreq.0.005.

Abstract: There is disclosed a method for producing a self-supporting ceramic body by oxidation of a molten precursor metal with a vapor-phase oxidant to form an oxidation reaction product and inducing a molten flux comprising said molten precursor metal through said oxidation reaction product. A second metal is incorporated into said molten flux during the oxidation reaction. The resulting ceramic body includes sufficient second metal such that one or more properties of said ceramic body are at least partially affected by the presence and properties of said second metal in the metallic constituent.

Abstract: A ceramic composition represented by the following general formula:Pb.sub.1-x La.sub.x (Zr.sub.y Ti.sub.1-y).sub.1-x/4 O.sub.3wherein O<x<1, O<y<1) is produced by a method which comprises adding a mixed solution of a titanium alkoxide and a zirconium alkoxide to an aqueous solution containing lead nitrate and/or lead acetate and lanthanum nitrate and/or lanthanum acetate thereby simultaneously effecting hydrolysis of said alkoxides and coprecipitation of lanthanum components, further adding an alkaline substance to the resultant system thereby effecting substantially thorough precipitation of lead and lanthanum components, and heating the produced precipitate.

Abstract: A composition for dielectric porcelain comprises Bi.sub.2 O.sub.3, TiO.sub.2 and RuO.sub.2.

Abstract: A polycrystalline body having a composition comprised of Y.sub.2-x Sr.sub.x O.sub.3-x/2 wherein x ranges from about 0.0015 to about 0.012.

Abstract: A transparent yttrium oxide ceramic is made by densifying a yttrium oxide powder without addition of dopants. The yttrium oxide powder is consolidated into a body of a predetermined shape and sintered to a density such that any remaining porosity is sealed from the surrounding atmosphere. The closed porosity body is then subjected to an elevated pressure and temperature to provide the body with substantially 100% of theoretical density. The resulting body has substantial transparency over the wavelength range of 0.6 .mu.m to 7 .mu.m.

Abstract: A zirconia sintered body comprising zirconia (ZrO.sub.2), yttria (Y.sub.2 O.sub.3) and titania (TiO.sub.2) [Y.sub.2 O.sub.3 /ZrO.sub.2 =at least 2/98 by mole and TiO.sub.2 /(ZrO.sub.2 +Y.sub.2 O.sub.3)=3/97 to 20/80 by mole] has a high translucence giving improved light transmittance. A zirconia sintered body comprising, in addition to ZrO.sub.2, Y.sub.2 O.sub.3 and TiO.sub.2, 0.1 to 3 mole % of an oxide of a rare earth element of the lanthanum group has a fluorescence-radiating property as well as a high translucence.

Abstract: A sinterable yttrium oxide powder is produced useful for pressureless sintering a compact thereof into an optically translucent or transparent body. The yttrium oxide powder has a specified particle size range and specific surface area. It is formed by preparing yttrium oxalate hydrate powder by means of the wet chemical oxalate method, comminuting the yttrium oxalate hydrate powder to a required degree and calcining the yttrium oxalate hydrate.

Abstract: There is provided a method of manufacturing a ceramic, wherein a ceramic material is covered with a foil of a metal selected from the group consisting of molybdenum, tungsten, platinum, and rhenium, sealed into an airtight vessel of tantalum or niobium, and then subjected to a hot isostatic press process. The method of the present invention can suppress coloration produced in the hot isostatic press.

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: The present invention discloses a novel black ceramic and a method of producing the same. This method employs a variety of industrial wastes and natural ore as starting materials to greatly decrease the cost of producing black ceramic materials. The black ceramic material of the present invention has many uses, such as, infrared radiating elements, fillers in plastics and rubbers, pigments in decorative architectural coatings and surfaces.

Abstract: A process for making a structural ceramic article, such as, an electromagnetic window, is disclosed, wherein the ceramic article is comprised of a densified mixture of not less than 50% by volume aluminum nitride and up to about 50% by volume boron nitride. The ceramic article of the present invention may be used as a shield or protective barrier such as an electromagnetic window for communication or detection devices on high speed transportation or delivery vehicles passing through extremely hostile environments, where it exhibits radar transparency, congruent vaporization kinetics, tailorable dielectric properties, improved thermal shock resistance, improved mechanical toughness and strength, improved spall resistance, improved recession rate, i.e. erosion rate and ablation rate, and high refractoriness.

Abstract: A piezoelectric ceramic powder comprises a solid solution of PbTiO.sub.3 and BiFeO.sub.3 wherein a portion of the iron content is replaced with manganese. A piezoelectric ceramic-polymer composite of 0-3 connectivity is disclosed using as the piezoelectric filler the manganese-doped solid solution.

Abstract: Several methods are set forth for preparing polymetallic spinels by coprecipitating two or more metal compounds in a proportion to provide a total of eight positive valences when combined in the oxide form in the spinel crystal lattice. The methods disclosed require coprecipitation of the metals in the hydroxide form or convertible to the hydroxide-oxide form, calcining the coprecipitate, and finally sintering the calcined material at about one-half its melting point or greater, thereby forming a spinel which has a density of greater than 50 percent of the theoretical density of spinel crystal. Also disclosed are techniques for preparing spinels having more than two metals incorporated into the spinel lattice, as well as a separate oxide phase associated with the spinel crystallites, and slipcasting compositions.

Abstract: A thickened binder composition which comprises from about 3 to about 20 weight percent colloidal alumina, from about 1 to about 8 weight percent aluminum chlorhydrate and from about 0.1 to about 0.4 weight percent of an inorganic acid selected from hydrochloric and nitric acids and from about 75 to about 95 weight percent water;the method for manufacturing the binder composition and a fiber article by blending the ingredients of the binder composition with each other and by impregnating or blending fibers with the binder composition to form a fiber containing composition followed by drying and calcining the fiber composition; andan article comprising alumina-containing fibers bound together with alumina.

Abstract: The present invention relates to low-expansion ceramics essentially consisting of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al.sub.2 O.sub.3), 24 to 80% by weight of titanium in terms of titanium oxide (TiO.sub.2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe.sub.2 O.sub.3), that major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide, and that the ceramics has 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. and a melting point of not lower than 1,500.degree. C., said coefficient of thermal expansion being maintained even after exposure 1,100.degree. C. for 1,000 hours, and a method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al.sub.2 O.sub.

Abstract: A sintered ceramic body of high toughness, consisting of an isotropic ceramic matrix (e.g. Al.sub.2 O.sub.3) and at least one therein-dispersed phase (ZrO.sub.2, HzO.sub.2) of ceramic embedment material formed from a powder consisting of particles having an average diameter from 0.3 to 1.25 .mu.m, wherein the ceramic embedment material is present in different enantiotropic solid modifications at the firing temperature of the ceramic body and below the firing temperature, whose densities are substantially different, and the ceramic body is shot through with extremely fine microfractures in high density.

Abstract: An agglomerated mixture includes 30-95% by weight of highly dispersed metal oxides produced by flame hydrolysis and 5-70% by weight of inorganic opacifiers that have at least one absorption maximum in the range between 1.5 and 10 .mu.m, selected from the group consisting of inorganic oxides and mixed oxides, carbides and nitrides. The invention also relates to a process of manufacturing the mixtures and to their use as heat-insulating material and the like.

Abstract: There is prepared pyrogenically produced silicon dioxide-mixed oxide having a BET surface area of 50 to 400 m.sup.2 /g which contains as a constituent of the mixed oxide:0.01 to 10 weight % zirconium dioxide or0.01 to 10 weight % iron oxide (ferric oxide) or0.01 to 9.9 weight % titanium dioxide.Because of the doping with the foreign oxide the silicon dioxide-mixed oxide is more temperature stable than the undoped silicon dioxide. The product can be used as thermal insulation either as unpressed material in free bulk form or as a compacted mixture.

Abstract: The invention provides a novel class of sintered refractory and abrasive ies composed mainly of one or a combination of metal diborides such as titanium diboride TiB.sub.2, chromium diboride CrB.sub.2, tantalum diboride TaB.sub.2 and the like admixed with a minor amount of one or more kinds of metal borides exemplified by MnB, Mn.sub.3 B.sub.4, Mn.sub.2 B, Mn.sub.4 B, TiB, Ti.sub.2 B.sub.5, Ti.sub.2 B, W.sub.2 B.sub.5 and Mo.sub.2 B.sub.5. The sintered body can be prepared by conventional powder metallurgical processes such as hot pressing or sintering of a green body shaped in advance by molding in cold with the powder blend of the above described components. Further advantages are obtained by admixing the powder blend with small amounts of one or more of binder ingredients of relatively low melting points such as cobalt borides, iron borides, nickel borides and an alloy of nickel and phosphorus. So-called infusion process is also applicable for the preparation of the inventive sintered body.