General Electric Company

The United States of America As Represented by the United States

Ronald H Arendt

Matthew J Curran

Wayne D Pasco

Joseph H Rosolowski

Marcus P Borom

Irvin C Huseby

Stephen L Dole

Mary F Garbauskas

Frederic Joseph Klug

Robert L Fleischer

Li-Chyong Chen

Patrick F Aubourg

Doped tungsten powder, or sintered tungsten bodies formed therefrom, having a fine dispersion of oxide particles of at least one metal from the group zirconium, hafnium, lanthanum, yttrium, and rare earth's are formed by the method of this invention. A mixture of a salt solution comprised of a soluble salt of the metal, and a tungsten blue oxide powder is formed. A hydroxide precipitating solution is admixed with the mixture to form a hydroxide precipitate of the metal on the tungsten blue oxide powder. The tungsten blue oxide powder and hydroxide precipitate are heated in a reducing atmosphere to form the tungsten powder having the dispersion of oxide particles. The doped tungsten powder can be consolidated and sintered to form tungsten bodies having a fine dispersion of the metal oxide.

Method of forming fine dispersion of ceria in tungsten

A silver tube with one open end is packed with a particulate mixture of reactants comprised of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x, Ca.sub.2 CuO.sub.3, cupric oxide and lead oxide, the open end of the packed tube is plugged with silver, the resulting closed tube is swaged to increase the density of the packed mixture, the swaged tube is wire-drawn, uniaxial pressure is applied to the wire orienting the Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x crystals with their c-axis parallel to each other forming an initial tape, the initial tape is fired to convert part of the Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x crystals to Bi.sub.2-y Pb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z crystals producing an intermediate tape containing dilated product, uniaxial pressure is applied to the resulting intermediate tape to remove the dilation in the product, and the pressed intermediate tape is fired to produce a tape comprised of silver enveloping a sintered body of Bi.sub.2-y Pb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z.

Preparation of tape of silver covered Bi-Pb-Ca;Sr-Cu-O oriented

A mixture comprised of an alkali chloride solvent and reactants comprised of bismuth sesquioxide, calcium oxide, strontium oxide and copper oxide, or precursors therefor, wherein the reactants are formulated to produce a superconducting reaction product, is heated to melt the chloride solvent in which the reactants then dissolve and react precipitating a Bi-Ca-Sr-Cu-O superconductive material which is comminuted to produce a sinterable powder.

Synthesis of Bi-Ca-Sr-Cu-O superconductive material

A process for producing a sinterable doped superconductive powder which contains a sufficient amount of superconductive compound which is at least coated with sufficient uranium-235 and/or plutonium-239 dopant atoms to enable the sinterable powder to be formed into a sintered superconductive body which can be irradiated with thermal neutrons to produce from about 0.25.times.10.sup.14 to about 5.times.10.sup.14 fission events per cubic centimeter of the resulting irradiated superconductive body, said superconductive compound being selected from the group consisting of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 .+-.x where x ranges from zero to 0.5, Bi.sub.2-y Pb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z where y ranges from 0.1 to 0.5 and z ranges from zero to less than 1, and mixtures thereof.

Bismuth-containing superconductors containing radioactive dopants

A particulate mixture comprised of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x where x ranges from 0 to 0.5, Ca.sub.2 CuO.sub.3, cupric oxide and lead oxide, wherein the Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x crystals are oriented with their c-axis at least sufficiently parallel to each other so as not to differ significantly from a common direction, is initially reacted producing an intermediate swollen partially reacted product which is pressed to remove the swelling and then sintered to produce a superconductive Bi.sub.2 yPb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z body where y ranges from 0.1 to 0.5 and z ranges from zero to less than 1.

Synthesis of Bi-Pb-Ca-Sr-Cu-O oriented polycrystal superconductor

A reactant particulate mixture comprised of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x where x ranges from 0 to 0.5, Ca.sub.2 CuO.sub.3, cupric oxide and lead oxide is formulated and reacted to produce superconductive Bi.sub.2-y Pb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z where y ranges from 0.1 to 0.5 and z ranges from zero to less than 1.

Synthesis of Bi-Pb-Ca-Sr-Cu-O superconductive material

A mixture comprised of an alkali chloride solvent and reactants comprised of oxides of lanthanum, an alkaline earth and copper, wherein the reactants are formulated to produce a superconducting reaction product, is heated to melt the chloride solvent in which the reactants then dissolve and react precipitating a lanthanum-alkaline earth-copper-oxygen superconductive material.

Synthesis of lanthanum-alkaline earth-copper-oxygen superconductive

An aluminum nitride ceramic body with a thermal conductivity of at least 0.5 W/cm.K at 25.degree. C. is produced by shaping a particulate mixture of aluminum nitride powder and an additive selected from the group consisting of CaF.sub.2, SrF.sub.2, BaF.sub.2 and mixtures thereof into a compact and liquid phase sintering the compact.

Alkaline earth fluoride additive for sintering aluminum nitride

An aluminum nitride ceramic body with a thermal conductivity of at least 0.5 W/cm.multidot.K at 25.degree. C. is produced by shaping a particulate mixture of aluminum nitride powder and an additive selected from the group consisting of YF.sub.3, ScF.sub.3, LF.sub.3 where L is La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er and a mixture thereof into a compact and liquid phase sintering the compact.

Rare earth fluoride additive for sintering aluminum nitride

A cofired structure comprised of a refractory metal metallization supported by a substrate free of large voids is produced by forming a liquid phase sinterable ceramic composition containing SiO.sub.2 in some form and a sulfate of an alkali metal and/or an alkaline earth metal, admixing the composition with an organic binding medium, shaping the mixture into a thin sheet, contacting the sheet with refractory metal metallization material, and cofiring the resulting structure whereby the free carbon produced by pyrolysis of the organic medium is removed by reaction with the sulfate before closed porosity is initiated.

Process for cofiring structure comprised of ceramic substrate and

A process of making a porous carbonate-containing structure for use in a molten carbonate fuel cell, wherein a suitable porous structure is prepared having disposed therein a metal salt selected from the alkali metals and the alkaline earth metals or mixtures thereof with at least a portion of the salt being a monobasic organic acid salt. The monobasic acid salt is converted to the carbonate in situ by heating in the presence of oxygen. Both electrode and electrolyte structures can be prepared. Formic acid is preferred.

Process for making structure for a MCFC

A particulate mixture of an alkali metal carbonate solvent, titanium oxide, and an alkaline earth reactant selected from the group consisting of barium oxide, strontium oxide, and mixtures thereof, is heated to melt the alkali metal carbonate solvent in which the reactants dissolve and react precipitating a titanate selected from the group consisting of barium titanate, strontium titanate and mixtures thereof.

Molten salt synthesis of barium and/or strontium titanate powder

A mixture of an alkali carbonate solvent salt, titanium oxide, an alkaline earth reactant selected from the group consisting of barium oxide, strontium oxide and mixtures thereof, and alkaline earth titanate seed is heated to melt the carbonate salt solvent in which the titanium oxide and alkaline earth reactant dissolve and react precipitating a titanate selected from the group consisting of barium titanate, strontium titanate and mixtures or solutions thereof onto said titanate seed producing large crystal sized powder, said titanate seed not differing significantly in chemical composition from the titanate being precipitated thereon.

Preparation of large crystal sized barium and/or strontium titanate

A particulate mixture of an alkali metal hydroxide solvent, barium oxide in excess of stoichiometric amount, and zirconium oxide in about stoichiometric amount, is heated to melt the hydroxide solvent in which the barium oxide and zirconium oxide dissolve and react precipitating ultrafine barium meta-zirconate (BaZrO.sub.3).

Preparation of ultrafine BaZrO.sub.3

Zircon, ZrSiO.sub.4, is retrieved from zircon sand comprised of ZrSiO.sub.4 crystals and contaminants including SiO.sub.2 and iron by comminuting an aqueous slurry of the sand with iron means exposing the contaminants, admixing the resulting comminuted sand slurry with concentrated nitric and hydrochloric acids producing ferric chloride in solution thereby removing its iron component, admixing the resulting suspension with a flocculating agent agglomerating the suspended particles, admixing the resulting agglomerated mass with concentrated hydrofluoric acid to dissolve its SiO.sub.2 component, recovering the resulting ZrSiO.sub.4, washing it with water and drying.

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Schenectady, NY, United States of America

Ronald H Arendt