Abstract: A burned chrome-containing refractory and method which provides a refractory having less than 5 ppm total soluble chromium. Such product is obtained by adding to the starting mix less than 10 wt. % (often less than 3 wt. %) zirconia, silica, zircon, or molybdic oxide either individually or in combination.

Abstract: A method for the production of refractory bricks, major components of which are a high proportion of chromium oxide and a small proportion of titanium oxide, makes provision for the chromium oxide and titanium oxide to be mixed, moulded and fired in a reducing atmosphere in order to achieve a solid solution of the titanium oxide in the chromium oxide. The fired intermediate units are then crushed. Other units are then formed from the sieve fractions of the crushed intermediate units and these are fired in a second firing operation to produce the refractory bricks. Non-fired chromium oxide is added to the sieve fractions of the crushed intermediate units and mixed in with this. The other units which are to be reductive-fired in the second firing operation are formed from this mixture.

Abstract: Abrasive material with particularly high abrasive performance is obtained in that the ceramic material contains an additive of 0.01 to 15 percent by weight, preferably 0.1 to 3 percent by weight of a chromium compound.

Abstract: A lanthanum chromite ceramic powder consisting essentially of 1 mol of LaCr.sub.1-x M.sub.x O.sub.3, where M is a divalent metal selected from the group of zinc, copper and mixtures thereof and x ranges from about 0.02 to 0.2, y mols of B.sub.2 O.sub.3, where y ranges from 0.0005 to 0.04, and z mols of La.sub.2 O.sub.3, where the ratio z/y ranges from 1 to 3, the powder is sintered to high density by firing a compact thereof at a temperature of about 1400.degree. C. in air or other atmosphere, and is particularly suited for use as interconnect material for solid oxide fuel cells.

Abstract: A sinter-reactive lanthanum chromite powder is prepared from the lanthanum chromite precursor LaCr.sub.1-x M.sub.x O.sub.3 (Adsorbate). The powder is crystalline, has the formula LaCr.sub.1-x M.sub.x O.sub.3, where M is selected from the group consisting of zinc, copper and mixtures thereof and x ranges from about 0.02 to 0.2, and sinters to densities higher than about 95% of theoretical density at temperature as low as 1400.degree. C. in oxidizing atmospheres. Sintering to such high density at temperatures in the vicinity of 1400.degree. C. makes the powder particularly suited for use as interconnect material for solid oxide fuel cells.

Abstract: A granular abrasive material is produced from a dispersion consisting of raw materials containing alumina, compounds containing silica and other additives. The dispersion is ground to a sinterable slip with a grain size of less than 1 micrometer. The slip is dried and may be pressed before being subjected to a multi-stage heating process to produce sintered corundum crystals.

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

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

Abstract: An electrical resistive material used for making e.g. a heating element for a thermal printing element. It is a Cr--Al--B--Zr--O alloy and is composed of a quaternary alloy and 15 to 25 at % of oxygen, wherein the quaternary alloy is composed of 2 to 25 at % of zirconium and a ternary alloy containing 35 to 55 at % of chromium, 2 to 23 at % of aluminium and 37 to 58 at % of boron.

Abstract: A vacuum switch contact material consists essentially of a mixture of Cu and Cr.sub.x O.sub.y (x=1 to 2, y=0 to 3) wherein Cr.sub.x O.sub.y is in a particulate state, the center part of the particles consists of Cr.sub.2 O.sub.3 (x=2, y=3), and the peripheral part of the particles consists of Cr (x=1, y=0). The Cr.sub.x O.sub.y particles having Cr.sub.2 O.sub.3 central part and Cr periphery can be formed by reducing the surface of Cr.sub.2 O.sub.3 particles. Cu may be infiltrated into the open pores of Cr.sub.x O.sub.y particles after a green compact of Cr.sub.2 O.sub.3 is formed. Alternatively, a mixture of Cr.sub.2 O.sub.y particles and Cu particles may be formed into a green compact, which may then be sintered. Still alternatively, a mixture of Cr.sub.2 O.sub.y particles and Cu particles may be hot-pressed.

Abstract: This invention provides an improved alpha alumina-based ceramic and a method to make the same. The improvement consists of the addition of a chromium-based nucleating agent. Particularly useful embodiments of the improved alpha alumina-based ceramic include abrasive particles and fibers.

Abstract: A burned, high-purity refractory, specifically a chrome-alumina, alumina-chrome and picrochromite composition, which contains less than 5 ppm total soluble chromium. Such products are obtained by adding to the starting mix less than 5 wt. % (often less than 3 wt. %) zircon, titania, molybdic oxide, boric acid, carbon black, or silica.

Abstract: A problem on removing dental restorative material can be to know its exact extent, otherwise sound tooth material may be unnecessarily removed. The inventive restorative material is made identifiable by adding crushed ruby powder, which fluoresces under standard dental blue light.

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: A method of producing self-supporting ceramic a ceramic composite 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 the ceramic body. A second polycrystalline ceramic or ceramic composite material is incorporated into the porosity of the ceramic or ceramic composite body to modify or contribute to its properties.

Abstract: The present invention relates to preparing refractory chromium-containing material and resides in local initiation of an exothermal reaction in a mixture of the following composition: a chromium-containing component, 8-20 mass % of a reducer selected from the group consisting of aluminium, magnesium, silicon, titanium, zirconium, or the alloys thereof, and 0.1-50 mass % of a filler, wherein as the filler use is made of periclase, sand, clay, refractory oxide, refractory scrap, wastes of blast-furnace processes, wastes of graphite or silicon carbide production, or an inorganic salt taken separately or in a mixture.

Abstract: A process for calcining a filter cake in a directly heated rotary kiln wherein part of the filter cake is separated from the entire mass of filter cake, the separated portion is predried and recombined with the remainder portion and the combined predried and remainder portion is calcined. The filter cake can be inorganic solids such as oxides of titanium, chromium (III), zinc and iron.

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

Abstract: This invention relates to a process for the preparation of a crystalline compound having an empirical formula LaCr.sub.x A.sub.1-x O.sub.4 .multidot.yH.sub.2 O where A is a metal selected from the group consisting of Mg, Sr, Ca and Ba, x ranges from 0.99 to about 0.7 and y ranges from 0 to 0.15. The process comprises adding a solution of the appropriate metal salts to a solution of ammonium hydroxide thereby precipitating a hydroxide gel intermediate, which is dried and calcined in air to yield the resultant crystalline compound which has a huttonite structure. Additionally, this invention relates to a process for the preparation of a ceramic powder having the empirical formula LaCr.sub.x A.sub.1-x O.sub.3, where A is a metal selected from the group consisting of Mg, Sr, Ca and Ba and x ranges from 0.99 to about 0.7. Finally, a ceramic composition having the empirical formula LaCr.sub.x S.sub.1-x O.sub.4 .multidot.yH.sub.2 O having a huttonite structure is also disclosed.

Abstract: A dome forming sliding gate filling composition for teeming ladles comprises chrome ore sand, quartz sand, and fine grained carbon black as an additive which improves dome formation or increases pourability.

Abstract: A ceramic chromium oxide coating produced by applying a conventional chromium oxide coating to a substrate and wholly or partly fusing the conventional chromium oxide coating by subjecting the chromium oxide coating to laser irradiation. The chromium oxide coating can optionally contain silica and/or alumina and less than 1 percent of metal.The chromium oxide coating can be employed for the internal and/or external protection of components in equipment for production and transport of oil and gas under water.

Abstract: Refractory compositions comprising at least eighty percent or more by weight Cr.sub.2 O.sub.3 densified by the addition of at least one-half percent and preferably about four percent TiO.sub.2 have about one-quarter percent to about fifteen percent by weight relatively finely divided monoclinic zirconia particles substantially uniformly dispersed therethrough to induce microcracks in the densified chromic oxide and improve thermal shock damage resistance of the refractory. Zirconia additions of up to at least five percent by weight exhibit the high glass corrosion resistance of similar densified chromic oxide compositions without zirconia.

Abstract: An oxide type solid lubricant is made up of a sintered composite ceramic mass of Cr.sub.2 O.sub.3 and Na.sub.2 ZrO.sub.3 and has a Cr.sub.2 O.sub.3 content in the range of from 20 to 50% by weight.

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

Abstract: Ceramic precursor mixtures containing a metal cation, a carbohydrate, and an anion capable of participating in an anionic oxidation-reduction reaction with the carbohydrate for continuous or batchwise drying and pyrolyzing to provide ceramic powders.

Abstract: The invention relates to a refractory composition comprising, by weight:(A) at least 70% of an aggregate based on refractory oxides,(B) from 7 to 25% of a matrix consisting of particles distributed between a fine fraction made up of a proportion of at least 95% of its weight of particles from 1 to 20 .mu.m in size, the median diameter of these particles being between 3 and 8 .mu.m, this fine fraction constituting 1 to 24% of the composition, and an ultrafine fraction consisting of a proportion of at least 70% of its weight of particles smaller than 1 .mu.m in size, the median diameter of these particles being between 0.3 and 0.8 .mu.m, this ultrafine fraction constituting 1 to 24% of the composition, the said matrix comprising(i) at least one oxide chosen from the group consisting of Al.sub.2 O.sub.3 and Cr.sub.2 O.sub.

Abstract: Fused cast refractory moldings having a random microstructure, which are near in size and configuration to the desired final shape, and process and apparatus used in their manufacture are described. The process includes rapid melting of the refractory material followed by controlled rapid cooling. Laminated composite fused cast refractories may be produced.

Abstract: Chrome oxide refractory materials which are a mixture of coarse fused chrome oxide particles and fine chrome oxide particles are disclosed as resistant to silica attack. The refractory materials have a Cr.sub.2 O.sub.3 content of at least about 98.5% and substantially no MgO.

Abstract: A process for the production of a precursor which is a polymeric material comprising at least one metallic or non-metallic element, oxygen and carbon and from which a ceramic material, e.g. a carbide, nitride, boride, or silicide, may be produced by pyrolysis, which process comprises reacting(1) a first reactant which comprises a compound or compounds of at least one metallic or non-metallic element having two or more groups reactive with hydroxyl groups, and(2) a second reactant which comprises at least one organic compound having two or more hydroxyl groups,said reaction being effected in a liquid medium in which the reactants are soluble and/or dispersible and in which the polymeric material which is produced by the reaction is insoluble or in which the polymeric material may be caused to be insoluble, precipitating the polymeric material in the liquid medium in particulate form, and recovering the polymeric material from the liquid medium in particulate form.

Abstract: A process for producing an improved quality alumina-silica-chromia fiber from a mixture of an alumina powder, a silica powder and a powder of a solid solution of chromia in alumina, providing a flowing melt, and forming fibers.

Abstract: Mixed lanthanide-magnesium aluminates and lasers using monocrystals of these aluminates.These lasers in particular incorporate two flash lamps for longitudinally pumping a monocrystalline rod of a magnetoplumbite-aluminate emitting visible or infrared light, amplified between a mirror, a polarizing prism being used for passing to the outside of the laser the amplified light beam. The aluminate is of formula:(La.sub.1-x Tr.sub.x).sub.1-y-v Mg.sub.1-z-t Al.sub.11-u+y+2z/3 Cr.sub.u O.sub.19-t-3v/3.in which Tr represents a) at least one single trivalent substance chosen from among lanthanides, Y.sup.3+, Sc.sup.3+, or b) at least one pair of lanthanides formed from a divalent element and a trivalent element, while retaining the electrical neutrality by adding aluminium or oxygen deficiencies, or any combination of (a) and (b); x is a number such that 0.ltoreq.x<1; y and v are numbers such that 0.ltoreq.y+v.ltoreq.0.4; z and t are numbers such that 0.ltoreq.z+t<1, provided that when z=t=0, y+v is .noteq.

Abstract: Porous ceramic greenware comprising finely divided ceramic filler, finely divided metal, and polyolefin controls shrinkage in fired shape. In a preferred embodiment the metal and ceramic filler are bound together with the clean burning polyolefin and a plasticizer. After molding the mixture into the final shape, the plasticizer is removed to introduce porosity into the shaped article. Next the article is heated to decompose the polyolefin which can exit as a gas through the pore openings. Finally, the article is fired to a high temperature to oxidize the metal to metal oxide which becomes sintered with the ceramic filler particles to form a sintered porous article where the oxidized metal bonds the filler particles together in the desired shape.

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: These lasers in particular have two flashlamps (30, 32) for longitudinally pumping a monocrystalline aluminate bar (28) emitting in the visible and near infrared, two mirrors (38, 40) for amplifying the light emitted by the bath, a polarizer prism (42) used for feeding the amplified light beam to the outside of the laser cavity. The magnetoplumbite-type aluminate has in particular the formula:La.sub.1-x Mg.sub.1-y-z Mt.sub.v Al.sub.11+x+2y/ 3-v O.sub.19-z(II)in which Mt represents a transition metal chosen from titanium and zirconium; x is a number such that 0<x<0.3; y and z are numbers such that 0.ltoreq.y+z.ltoreq.1 with 0.ltoreq.y.ltoreq.1 and 0.ltoreq.z.ltoreq.1; v is a number such that 0<v<1.

Abstract: A refractory product is shown in the form of a dense sintered alumina-chromia, zirconia-alumina-silica, zirconia-alumina body, or zirconia-chromia-alumina having less than about 8% of homogeneously distributed closed porosity formed by sintering an intimate interdispersion of fine particles of alumina-chromia, zirconia-alumina-silica, zirconia-alumina, or zirconia-chromia-alumina.

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: The present invention is characterized by ceramic materials comprising ceramic sintered bodies consisting of (1) 1-90 wt % chromium carbide and the remainder carbonic titanium nitride; (2) 1-90 wt % chromium carbide, 0.1-5 wt % B.sub.4 C and the remainder titanium carbo-nitride; or (3) either of the above compositions plus less than 95 wt % of a metal boride such as Ti or Zr. Such ceramic sintered bodies are used for cutting tools or wear-resistant machine parts because of their high density, high hardness and high strength.

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: The invention relates to a sintered body of a ceramic composite material based on alumina, refractory hard phases and ZrO.sub.2, HfO.sub.2 and/or partially stabilized ZrO.sub.2 with a relative density of more than 98%. The sintered body according to the invention has chromium integrated in amounts corresponding to in all 1-20 weight % and ZrO.sub.2, HfO.sub.2 and/or partially stabilized ZrO.sub.2 present as 2-16 weight % with these latter phases present to more than 70% in the tetragonal crystal modification. Furthermore, the refractory hard constituents are present as particles with a grain size of less than 10 .mu.m and/or as whiskers or fibers with a diameter of less than 5 .mu.m and a length/diameter ratio of >10.

Abstract: An chrome-alumina refractory brick prepared by pressing and firing a mixture consisting essentially of about 15 to 90 percent by weight of a fused chrome-alumina grain, 5 to 25 percent by weight of chromic oxide, up to 30 percent by weight of a zirconia-containing grain, and the balance alumina.

Abstract: Heavy ceramic shaped material with a content of at least one of the components magnesia, fired dolomite, chromite and spinel, characterized by a microcrack system substantially homogeneously distributed in the shaped material structure, as well as process for producing such a heavy ceramic shaped material and the use thereof.

Abstract: A spinel type ceramic sintered body is provided starting from a chromiferous slag which is a waste discharged from sodium chromate production, said sintered body being reproducable by selecting the mole ratios of R.sub.2 O/MgO to 0.9-2.0 and SiO.sub.2 /MgO to 1-6 wherein R represents collectively Al, Fe and Cr, the sintered body having high thermal conductivity falling within the range of 1.3-2.5 kcal/mh.degree. C., specific electric resistance falling within the range of 10.sup.2 -10.sup.7 cm high mechanical strengths and unique coloration and which can be used as a functional tile.

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 porous refractory hard metal composition is disclosed which is formed by removing the metal compound from a substantially interwoven matrix composition comprising one or more refractory hard metals and a metal compound. The interwoven matrix composition, in a preferred embodiment, may comprise Al.sub.2 O.sub.3 and TiB.sub.2, ZrB.sub.2, or a mixture of the two refractory hard metals.

Abstract: Large, dense chromic oxide refractory blocks containing from about 80% to about 98% chromic oxide are made by firing a green block comprising, in addition to the chromic oxide, titania and a colloidal silica having a surface area of at least about 90 m.sup.2 /g. Blocks having porosities as low as 0% are made in either an oxidizing or a reducing atmosphere. The blocks are crack-free and have a good resistance to corrosion by molten glass.

Abstract: A silicon carbide powder consisting of an aluminum component such as aluminum nitride and aluminum oxide and a chromium component such as chromium carbide as essential ingredients and if desired, a rare earth element such as yttria is sintered into an integrated molded article. This sintered article has excellent strength and toughness and a markedly reduced tendency to undergo corrosion when brought into contact with iron at high temperatures.

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: Porous metal structures are especially useful as abradable seals in axial flow compressors. Carefully defined oxide content and density provide a superior combination of abradability and particulate erosion resistance. The seals are comprised of 1-30 weight percent oxide and have 27-38 percent of the solid metal density. A preferred seal is made by plasma arc spraying a mixture of 80Ni-20Cr and polymethylmethacrylate powders and then heating the resultant deposit in air to about 315.degree. C. to cause the polymer to flee. The nichrome seal will have less than 15 percent oxide and a density of about 2.7 g/cm.sup.3, about 32 percent of the solid metal density.

Abstract: A dielectric ceramic composition comprises a main component comprising, in percent by weight, 32 to 47% SrTiO.sub.3, 26.5 to 46% PbTiO.sub.3, 8 to 16% CaTiO.sub.3, 5 to 16% Bi.sub.2 O.sub.3, and 3 to 10% TiO.sub.2 ; ZnO in an amount of 1 to 3.8% of the total composition; and SiO.sub.2 in an amount of 1 to 3.8% of the total composition. The dielectric ceramic composition having a high dielectric constant, a small voltage dependence of dielectric properties, and a low firing temperature.