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: A method for producing materials having a high purity, which comprises forming an oxidation reaction product of a parent metal and an oxygen-containing vapor-phase oxidant, comminuting the resulting ceramic body and leaching any non-oxidation reaction product and/or corresponding filler materials therefrom, and recovering said substantially pure materials.

Abstract: A method of producing self-supporting ceramic bodies having a modified metal-containing component includes first providing a self-supporting ceramic body comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a molten parent metal precursor with an oxidant, and (ii) an interconnected metal-containing component at least partially accessible from one or more surfaces of said ceramic body. The surface or surfaces of the ceramic body is contacted with a quantity of foreign metal different from said interconnected metal-containing component at a temperature and for a time sufficient to allow for interdiffusion, whereby at least a portion of said metal-containing component is displaced by said foreign metal. The resulting ceramic body, having an altered metal-containing component, exhibits modified or improved properties.

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 silica shaped body comprising a multiplicity of interconnected secondary particles of amorphous silica, voids interspersed between the secondary particles, and at least one inorganic inactive substance selected from among carbonaceous substance, carbide, nitride and metallic oxide and physically united with the secondary particles, is prepared by containing a siliceous material, calcareous material and water to a hydrothermal synthesis reaction with heating and stirring under an elevated pressure to obtain an aqueous slurry of secondary particles of calcium silicate crystals, followed by carbonation, shaping and drying.

Abstract: A method is provided for producing a self-supporting ceramic body comprising a polycrystalline material comprised of the oxidation reaction product of a parent metal and having therein one or more channels which inversely replicate the geometry of a configured fugitive metal. The method includes providing an assembly of the configured fugitive metal and the parent metal, optionally including a bed of permeable filler, and heating the assembly to form a body of molten parent metal. The molten parent metal is oxidized under selected conditions to grow the polycrystalline material to engulf the configured fugitive metal (and to infiltrate the filler, if the filler is present) and to cause the fugitive metal to disperse into the engulfing polycrystalline material thereby leaving behind as the one or more channels the space formerly occupied by the configured fugitive metal.

Abstract: A process is comprised of continuously producing a fine ceramic powder by drying at supercritical conditions. The feed is a sol of ceramic oxides or hydrous oxides which is continuously pressurized and heated to in excess of the critical temperature and pressure of the sol solvent. The solvent transforms to a gas and separates from the fine particulate ceramic oxide powder, which remains in a highly divided state.

Abstract: A manganite type composition of the formulaMn.sub.3-x-y-z Ni.sub.x Co.sub.y M.sub.z O.sub.4 (I)wherein M is at least one metal selected from Cu, Zn and Cd, y and z range from 0 to 1, and (x+y+z) is lower than 2. This composition can also contain a doping agent. The composition is either a particulate composition wherein at least 90% of the particles have a regular form and a size lower than 5 .mu.M or a ceramic material having a density greater than 94% of the theoretical density. The composition is useful in the production of thermistors.

Abstract: An assembly for the preparation of ceramic composite structures includes a segmented container within which a permeable filler is retained and a parent metal body is contacted with the bed of permeable filler. The segmented container is comprised of one or more segments made of a material, such as an INCONEL alloy, which has a coefficient of thermal expansion which is significantly greater than that of the filler. The segments are arranged to define between or among them one or more expansion joints which are effective to accommodate circumferential thermal expansion of the segments to thereby inhibit or prevent volumetric expansion of the container. A method of forming ceramic composite structures includes heating the resulting assembly in the presence of an oxidant to melt and oxidize the parent metal, e.g., aluminum, to form a polycrystalline material comprising an oxidation reaction product which grows through the mass of filler to embed it and thus form the composite structure.

Abstract: A method for producing an alumina of high purity, which comprises forming an oxidation reaction product of an aluminum parent metal and an oxygen-containing vapor-phase oxidant, comminuting the resulting ceramic body, and leaching any non-alumina materials therefrom, and recovering said substantially pure alumina material.

Abstract: A process is described for the preparation of a ceramic green body by hydrolyzing at least one alkoxide selected from each of two specified groups to form a dispersion of their reaction product, concentrating the dispersion to a sediment without drying it, and admixing a binder and a plasticizer with the sediment to make a ceramic slip formulation. A release agent can optionally be admixed. The slip formulation is then cast as a ceramic green body. The proportions of alkoxides can be adjusted, as desired, to produce a ceramic green body which is dielectric and useful for microcapacitors or as a conductor.

Abstract: Suspensions of ceramic or metallic colloidal particles having a high volume fraction (greater than about 55 vol. %) solid particles are provided in a pourable form. The pourable suspension includes at least about 55 vol. % ceramic or metallic colloidal particles, an aqueous vehicle, and an acrylic acid-based polymeric polyelectrolytic dispersant. Such suspensions can be prepared by mixing the colloidal particles in a staged order of addition and under a high shear rate with the other components. The suspensions are suitable for making ceramic or metallic articles, and can exhibit a low viscosity.

Abstract: Ceramic foams in which the open cells are connected by a three-dimensional, substantially continuous ceramic matrix formed of interconnected hollow ligaments, are made from an open-cell, reticulated precursor metal, i.e. a metal foam. The precursor metal first is treated so as to allow a support coating to form thereon, and thereafter the coated precursor is heated above the melting point of the metal in the presence of an oxidant to form an oxidation reaction product.

Abstract: A method of producing self-supporting ceramic structures comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a body of molten parent metal with an oxidant, and (ii) interconnected porosity at least partially accessible from one or more surfaces of said ceramic body. A second polycrystalline ceramic material is incorporated into the porosity of said ceramic body to modify or contribute to its properties.

Abstract: A ceramics-based manufacturing material and a coating material are disclosed, both of which are used in high-temperature structures and applications. The ceramics-based manufacturing material may be used for building structural blocks or members, such as refractory bricks, that require the mechanical strength and thermal resistance when they are exposed to the high temperatures of 1,500.degree. C. or above. Those bricks made of the material disclosed provides the mechanical strength and heat resistance better than the conventional ones. The coating material may be used for forming a thermal resistant layer on metal or other material bases. Both materials have substantially the similar compositions, either of which may have the alternative use, such as the manufacturing material or the coating material. Simply adding an appropriate amount of water to either makes it a coating material. In either case, the requirements for the high temperature resistance and mechanical strength can be satisfied.

Abstract: Crystalline solid solutions and diphasic mixtures having a composition of Ca.sub.1-x M.sub.x Zr.sub.4 P.sub.6 O.sub.24, where M is Ba and/or Sr and X is between about 0.25 and 0.75, have been produced which display both low anisotropy and near zero bulk thermal expansion behavior.

Abstract: A metal alcoholate is treated with a quantity of water such that the molar ratio of the quantity of water to the quantity of metal alcoholate is lower than the valency of the metal in the alcoholate.

Abstract: A process of forming a refractory mass on a surface, which process includes spraying against that surface a mixture of refractory particles and oxidisable particles which react exothermically with oxygen to generate sufficient heat to soften or melt at least the surfaces of the refractory particles and so bring about formation of said refractory mass, and causing the sprayed mixture to be heated sufficiently to cause the oxidisable particles to undergo such exothermic reaction, the granulometry of the particles which are sprayed in the mixture being such that the mean of the 80% and 20% grain sizes of the refractory particles is greater than the mean of the 80% and 20% grain sizes of the oxidisable particles and that the size range spread factor of the refractory particles is at least 1.2.

Abstract: The present invention resides in the provision of a basic unburned brick or castable refractory which contains none or an extremely small amount of components which exert a harmful influence on molten steel such as phosphorus, sulfur, and boron and which has a high hot strength.

Abstract: An improved refractory composition especially adapted for use as a gunning mix is made of aggregate (for example, periclase) and a bonding material (for example, aluminum sulfate, boric acid, and citric acid) to which is added attapulgite. The composition may also contain other materials, as is known in the art.

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

Abstract: A voltage-dependent ceramic resistance (varistor) based on ZnO and other addition elements, mostly in the form of oxides, is prepared, in that the addition elements are added to a suspension of ZnO powder in H.sub.2 O as chemical substances in the form of aqueous, mutually compatible, non-separating solutions of organic salts, acids, complex compounds and/or colloids, the suspension/aqueous solution formed in this manner is dried in the presence of air in a spray dryer, the free-flowing powder/granules prepared in this manner are pressed to a body and the pressed body is subjected to heat treatment, in order to decompose the organic substances, convert them into oxides, remove the decomposition products, and is finally sintered by successive heating to 650.degree. C., 900.degree. C. and 1100.degree. to 1300.degree. C. The water-soluble chemical substances to be used are preferably organic salts such as formates, acetates, lactates, tartrates, citrates, ammonium citrates and ammonium tartrates.

Abstract: A finely divided metal oxide powdery composition, preferably with a narrow particle size distribution, is produced from a particulate, sol-gel derived composition containing agglomerates by heating the particulate composition in the presence of an effective amount of a composition which decomposes upon heating and forms a gas to break at least a portion of the agglomerates so as to yield the desired finely divided ceramic particle composition. Examples of suitable gas-forming agents for use in the present invention include the ammonium salts or amides of organic and inorganic acids, volatile acids, and gases dissolved in a suitable solvent, such as water, alcohol or ammonia.

Abstract: Described herein is a high toughness ceramic composite of the fiber reinforced type, comprising: metal fiber integrally anchored in a ceramic matrix and having a shape of triangular waves forming bent portions alternately on the opposite sides thereof with an angle .theta. of the bent portions in a range between 60.degree. and 165.degree., a ratio of d/H (a ratio of the amplitude H of the waves to the diameter d of the fiber) in a range between 0.025 and 0.6, and a ratio of .rho./d (a ratio of the radius of curvature .rho. at the apex of the bent portion to the fiber diameter d) greater than 1, inclusive.

Abstract: The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.

Abstract: A process for preparing ceramic nitrides and carbonitrides in the form of very pure, fine particulate powder. Appropriate precursor is prepared by reacting a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

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 relates to a two-part gunning refractory composition wherein fine powders of a refractory aggregate and superfine refractory powders are previously made into the form of a slurry containing therein a deflocculant, thereby reducing the amount of aluminous cement and also reducing the amount of water to achieve a deposit applied by gunning having a quality comparable to one produced by casting.

Abstract: A piezoelectric ceramic powder is, together with a binder, processed to a granulate. This granulate is mixed with a pearl polymer to a mixture. The mixture is pressed to a suitable shape, and then in a first firing step the binder and the pearl polymer are fired out. Preferably the first firing process is followed by a second firing step for sintering. Thereafter mechanical fabrication may take place, to give the end product its shape. The firing out of the pearl polymer results in a porous piezoelectric ceramic, with which, when used in an ultrasonic transducer, a high transducer effectiveness, sharp ultrasonic pulses with little edge radiation as well as a good electric and acoustic adaptation can be achieved.

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: Novel self-supporting ceramic structures are produced by the oxidation reaction of a molten metal precursor with a vapor-phase oxidant to form an oxidation reaction product. Molten metal is drawn through the oxidation reaction product towards the oxidant to cause continued growth of the product at the interface between oxidant and previously formed product. This reaction or growth is continued to form a thick, self-supporting ceramic body. The resulting ceramic material of the polycrystalline growth product consists essentially of an oxidation reaction product and, optionally, one or more non-oxidized constituents of the metal precursor.

Abstract: Preparation of a ceramic green body by hydrolyzing two groups of alkoxides to form a dispersion of their reaction product, concentrating the dispersion to a sediment without drying it, and admixing a binder solution, plasticizer and release agent with the sediment to make a ceramic slip formulation. The slip formulation is then cast as a ceramic green body. The proportions of alkoxides can be adjusted to produce a ceramic green body which is dielectric and useful for microcapacitors.

Abstract: A sliding-contact type ceramics article having a high density portion for increasing the mechanical strength of its slide-contact portion with an associated article. A method for manufacturing such a sliding-contact type ceramics article which is characterized in that, at first a compact body having a configuration which is approximate to a final article is molded in such a manner that a slide-contact portion with an associated article is intensively compressed, and then the compact body is grinded to obtain a compact body of a final configuration.

Abstract: A low expansion ceramic composition is represented by the formula Ca.sub.0.5 Ti.sub.2 P.sub.3 O.sub.12 in which up to 100 percent of the Ca is replaced by one or more of the other alkaline earth metals and alkali metals, the alkali metals being selected from the group consisting of Na, Li, K and combinations thereof and substituted in the ratio of two units of alkali metal for each unit of Ca replaced. Up to 100 percent of the Ti is replaced by one or more members selected from the group consisting of Zr, Sn, Nb, Ta and Cr. For each unit of Cr replacement an approximately equal unit of alkali metal is added. For each unit of Nb and/or Ta replacement an approximately equal unit of Na and/or K replaces a unit of Ca. Up to 100 percent of the P may be replaced by Si and/or S. The total of the amounts of Ca, other alkaline earth metals, Li, K, Ti, Sn, Nb, Ta and Cr is greater then zero. Preferably up to 100 percent of the Ca is replaced by Na, and up to 100 percent of the Ti is replaced by Zr or NaCr.

Abstract: Process for the preparation of a powder suitable for fritting.The process comprises the stages of forming an emulsion, fractionating the emulsion into microdroplet form, which are solidified, dried and heat treated. According to the invention, the emulsion is formed from at least one powder suspended in a solution of at least one precursor salt, i.e. whereof the cation or cations are constituent elements of the powder to be formed.Application to the replacement of metal parts by ceramic parts in heat motors.

Abstract: A high temperature resistant refractory mortarless joint wall and method made from pre-formed, unburned plastic refractory blocks having siliceous clay, and from ten percent to seventy-five percent pyrophyllite, by weight, and workability from twenty percent to forty percent when erected before drying and firing.

Abstract: A process for preparing fine fibers (or whiskers) consisting of carbon and silicon is disclosed, in which a mixed gas of transition metal compound(s), organo-silicon compound(s) and optionally carbon compound(s) is reacted at a high temperature, such as in the range of 700.degree. to 1,450.degree. C.

Abstract: An improved process and apparatus for producing sintered material such as dead burned clay, dolomite, magnesite or periclase with the highest particle specific gravity capable from each material. A grinding mill produces raw material which is 100% minus 20 mesh. The ground raw material is supplied to a suspension type preheater and then to a stationary flash calcining system where the material is soft burned at temperatures in the range of 1000.degree. to 1200.degree. C. From the calcining system, the calcined material is immediately supplied to hot briquetting machine where briquettes or nodules are formed. The hot nodules at a temperature of approximately 800.degree. C. are then immediately supplied to a rotary kiln which serves as a sintering furnace where the soft burned material is dead burnt at a temperature in the range of 1650.degree. to 1850.degree. C. Hot spent combustion gas from the sintering furnace is supplied to the calcining furnace to serve as preheated secondary air for combustion.

Abstract: A tough Si.sub.3 N.sub.4 ceramic composite is provided by incorporating a ternary oxide additive containing hafnia, titania and zirconia. The ternary oxide additive consists essentially of 60 to 85 mole percent hafnia, 10 to 30 mole percent titania and 10 to 30 mole percent zirconia, and is added to the Si.sub.3 N.sub.4 in a proportion ranging from about 10 to about 50%, by volume of ternary oxide additive, based on the overall composition. The ceramic composites are prepared by providing a mixture of the Si.sub.3 N.sub.4 and the ternary oxide additive, forming the mixture into a predetermined shape, e.g. by cold pressing, and sintering the shape at an appropriate temperature, to solidify and densify the shape.

Abstract: Ceramic shaped articles are disclosed which are formed of dense, non-metallic, mechanically resistant materials and contain eutectic constituents consisting of zirconium oxide, hafnium oxide and at least one other high-melting oxide and mixtures thereof. The composition exhibits excellent hardness, wear properties and bending strength. A method for preparing the articles is also disclosed wherein the appropriate mixture in a hypoeutectic, eutectic, or hypereutectic ratio is heated to its melting point, poured into a preheated mold and cooled.

Abstract: A refractory containing refractory aggregate, clay binder, finely divided metallic powder and short length organic fibers.

Abstract: The present invention provides a method for controlling the carbon content of dewaxed carbide preforms in a carbon containing furnace. The method includes the steps of placing the preforms in a carbon containing furnace and then heating the furnace to a predetermined temperature range between 800 and 1100 degrees Centigrade. At that temperature, a mixture of methane and hydrogen is introduced into the furnace chamber such that the amount of methane is between 10 and 90 percent of the amount of methane present at equilibrium for the reaction C.sub.solid +2H.sub.2 .revreaction.CH.sub.4. The furnace chamber is maintained at its temperature for a first time period sufficient for the chemical reaction XC+2H2.revreaction.X+CH.sub.4 (where X is selected from the group of W, Ti, Ta, Hf and No) substantially reaches equilibrium but shorter than the a second time period in which the reaction C.sub.solid +2H2.revreaction.CH.sub.

Abstract: Metal vaporization from precious metals is reduced by applying to the surface of the metal a flame sprayed coating comprising a refractory material and a glass.

Abstract: Novel aqueous inorganic particle slurries, wherein some of the particles have had their charge potential altered to a sufficient extent to prevent segregation or settling of the particles, are described, along with a method for their preparation. The method of forming slurries of negatively charged particles comprises treating some of the particles with a cationic agent to reduce their charge and mixing these treated particles with the remainder of the particles to form a thick, cream-like flowable composition of a thixotropic nature. When slurries of positively charged particles are to be formed, an anionic agent is used instead of a cationic agent.

Abstract: A method of reoxidizing a partially-reduced ceramic. The partially reduced eramic is heated in a chamber having a non-oxidizing atmosphere. An oxidizing gas is then introduced into the chamber at a rate which is sufficiently slow that cracking will not occur.

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 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: Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

Abstract: A toast guard made of a heat absorbent ceramic piece molded in the shape of a slice of bread, but slightly smaller in size and thickness than a slice of bread. The ceramic piece is used in the toasting process of an ordinary multi-slotted household toaster when some of the slots of the toaster are filled with slices of bread and some of the slots are vacant. The ceramic piece enables the toast to be darkened to the same degree on both sides and prevents the excessive darkening or burning of the side of the toast adjacent to a vacant slot in the toaster.

Abstract: Precursors, particularly of non-oxide ceramics, are prepared by special seeding, under carefully controlled conditions. Such procedures can lead to the preparation of unique powders, which may be useful, for example as abrasives, or further processed in special manner to prepare a variety of metal substances. Such procedures can permit final firing to sintered product.