By Precipitating Patents (Class 505/738)
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Patent number: 5457088Abstract: To prepare a phase-pure, ceramic oxide superconductor which contains, in addition to copper, at least one alkaline earth metal from the group comprising Ba, Sr and Ca, and at least one metal from the group comprising Y, La, Tl, Pb and the rare earths, for example of YBa.sub.2 Cu.sub.3 O.sub.7-x, a solution is prepared which contains the metal components in the atomic ratios of the superconductor. The metals are precipitated as oxalates by combining this solution with an oxalic acid solution, the mixture of the oxalates is separated off, dried and decomposed to form the oxides, and the latter are subsequently sintered at temperatures of from 700.degree. to 900.degree. C. in the presence of oxygen to form the superconductor. In this process, the heating of the metal oxalates and the oxides formed therefrom up to 700.degree. C. is carried out at a maximum oxygen partial pressure of 50 mbar, preferably in an inert gas.Type: GrantFiled: September 7, 1990Date of Patent: October 10, 1995Assignee: Hoechst AktiengesellschaftInventor: Winfried Becker
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Patent number: 5449660Abstract: A method of producing a compound oxide of elements including at least one of thallium, bismuth, lead, antimony, yttrium, each of rare earth elements, each of transition metal elements, each of alkali metal elements and each of alkaline earth metal elements. The method is comprised of the steps of (i) reacting at least one of carbonate, basic carbonate, hydroxide and co-precipitates of each of the above-mentioned elements with an amount of citric acid that is less than the weight equivalent of citric acid needed to form a completely citrated compound, and (ii) calcining the partly citrated compound. The co-precipitate can be one of a carbonate, a basic carbonate and a hydroxide of each of the above-mentioned elements.Type: GrantFiled: March 16, 1993Date of Patent: September 12, 1995Assignees: Nissan Motor Co., Ltd., Seimi Chemical Company, LimitedInventors: Fumio Munakata, Mitsugu Yamanaka, Susumu Hiyama
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Patent number: 5395821Abstract: Metal oxide superconductor powder precursors are prepared in an aerosol pyrolysis process. A solution of the metal cations is introduced into a furnace at 600.degree.-1000.degree. C. for 0.1 to 60 seconds. The process produces micron to submicron size powders without the usual loss of the lead stabilizer. The resulting powders have a narrow particle size distribution, a small grain size, and are readily converted to a superconducting composition upon subsequent heat treatment. The precursors are placed in a metal body deformed to form a wire or tape and heated to form a superconducting article. The fine powders permit a substantial reduction in heat treatment time, thus enabling a continuous processing of the powders into superconducting wire, tape or multifilamentary articles by the powder-in-tube process.Type: GrantFiled: October 30, 1992Date of Patent: March 7, 1995Assignee: Martin Marietta Energy Systems, Inc.Inventors: Donald M. Kroeger, Huey S. Hsu, Jorulf Brynestad
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Patent number: 5334557Abstract: A method of preparing a powder of YBaCuO [phase 123] suitable for forming by drawing-lamination, which includes:preparing a powdered reactive mixture of precursors of purity greater than 99% and with a stoichiometry accurate to within less than 1%,binding this powdered reactive mixture to form intermediate pieces less than two millimeters in thickness which are placed in an oven so that their contact with a support is as small as possible,a heat treating the intermediate pieces,dry grinding the intermediate pieces to obtain grains of said powder with an average diameter of the order of a few .mu.m.Type: GrantFiled: March 3, 1993Date of Patent: August 2, 1994Assignee: Alcatel Alsthom Compagnie Generale d'ElectriciteInventors: Grard Duperray, Claudette Audry, Francoise Ducatel
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Patent number: 5290759Abstract: Superconducting precursors, which can be made into metal oxide superconductors such as YBa.sub.2 Cu.sub.3 O.sub.6+x, and a process for their manufacture by the coprecipitation of 1-2-3 nitrates using inexpensive precipitating agents such as alkali hydroxides, carbonates and bicarbonates. The process involves preparing a stoichiometric mixture of Y, Ba and Cu nitrates, which is then combined with a solution containing an excess of NaOH/K.sub.2 CO.sub.3, KOH/K.sub.2 CO.sub.3, NaOH/Na.sub.2 CO.sub.3, or KOH/Na.sub.2 CO.sub.3, which causes the precipitation of the precursor. The suspension containing the precipitate is filtered and then washed wiThe invention of this application was made and conceived at least in part with United States Government support and the United States Government has certain rights in the invention.Type: GrantFiled: April 3, 1992Date of Patent: March 1, 1994Assignee: University of Houston-University ParkInventors: J. T. Richardson, Dan Luss, D. Morgan, M. Maric
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Patent number: 5252314Abstract: Guanidine oxalate is used as a precipitating agent in the coprecipitation of multicomponent oxide powder precursors. A solution of a soluble inorganic salt is combined with a solution of guanidine oxalate. A resultant metal oxalate is precipitated from the solution and can thereafter be subjected to heat to convert the metal oxalate into a multicomponent ceramic powder.Type: GrantFiled: November 30, 1990Date of Patent: October 12, 1993Assignee: Case Western Reserve UniversityInventors: Mark R. DeGuire, Warren H. Philipp
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Patent number: 5244872Abstract: An oxide superconductor having the following formula:Pb.sub.2 Sr.sub.2 Ca.sub.1-p Ln.sub.p Cu.sub.3 O.sub.q orPb.sub.1-x Cu.sub.x Sr.sub.2 Ca.sub.1-y Ln.sub.y Cu.sub.2 O.sub.zwherein Ln represents a rare earth element, p is 0.3-0.7, q is 7.8-8.2, x is 0.2-0.5, y is 0.3-0.7 and z is 6.8-7.2 is prepared using a coprecipitation method. An acetic acid solution of carbonates, acetates or nitrates of Pb, Sr, Ca, Cu and Ln is mixed with an aqueous solution of oxalic or tartaric acid, or a lower alkyl ester thereof. The mixture is reacted to precipitate the Pb, Sr, Ca, Cu and Ln as oxalates or tartarates and the precipitates are dried and sintered to obtain the oxide superconductor.Type: GrantFiled: November 1, 1991Date of Patent: September 14, 1993Assignees: International Superconductivity Technology Center, Sanyo Electric Co., Ltd., Kyocera Corporation, Tokyo Gas Co., Ltd.Inventors: Takaaki Ikemachi, Takashi Kawano, Shin-ichi Koriyama, Hisao Yamauchi
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Patent number: 5223480Abstract: A novel method for forming homogeneous silver high temperature superconductor (HTS) composites. The novel method comprises a chemical coprecipitation of silver, barium, yttrium, and copper salts solutions, followed by calcination and milling processes. The novel method has an advantage of retaining all the virtues immanent in a composite HTS, for example, increased critical current density (Jc), and improved mechanical properties, while bypassing extant and deficient methodologies for forming a composite, the deficient composites characterized by heterogeneity.Type: GrantFiled: April 22, 1991Date of Patent: June 29, 1993Assignee: Eastman Kodak CompanyInventors: Ashok K. Agarwala, Paul A. Christian, Kenneth B. Quinn
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Patent number: 5206215Abstract: A process for obtaining precursors for high critical temperature superconductor ceramics by precipitating salts which are insoluble in water comprises the following stages: A starting solution of soluble salts is prepared in which the cations are in the stoichiometric proportions of the required superconductor phase. A first full precipitation is carried out of a first series of cations at a first value of pH. The first precipitates obtained is filtered out and washed and the filtrate is retained. The pH of the filtrate is changed to a second value and the residual cations are precipitated. The second precipitate is filtered. The first and second precipitates are homogenized. The product obtained is dried, calcined, and ground.Type: GrantFiled: March 13, 1992Date of Patent: April 27, 1993Assignee: Alcatel Alsthom Compagnie Generale d'ElectriciteInventors: Gerard Duperray, Francoise Ducatel
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Patent number: 5200390Abstract: A fine stoichiometric superconductor powder may be co-precipitated from the addition of appropriate metal compound powders in ammonium carbonate. The co-precipitated powder is very homogeneous because the reaction progresses in liquid solution. For example, YBa.sub.2 Cu.sub.3 O.sub.7-x superconducting powder may be prepared by the co-precipitation of yttrium oxide, copper (I) acetate, copper (II) acetate and barium acetate. The acetates precipitate by nucleating on the yttrium oxide particles. The process permits a relatively wide window of starting reactant proportions yet still produce ceramics having superconductive properties.Type: GrantFiled: May 21, 1990Date of Patent: April 6, 1993Assignee: Motorola Inc.Inventor: Wei-Yean Howng
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Patent number: 5162299Abstract: A superconducting oxide precursor material is prepared by dissolving soluble compounds containing the non-oxygen elements of the oxide in concentrated nitric acid, in which a decomposing agent for the nitrate of the nitric acid selected from urea and sucrose and an oxidizing/reducing agent selected from hydrogen peroxide and ammonium nitrate have also been dissolved. The acid solution is concentrated by heating until the liquid component is pyrolyzed, leaving a superconducting oxide precursor material residue. The precursor material is produced with a relatively high oxidation state, but is normally further oxidized to reach a superconducting state.Type: GrantFiled: December 14, 1990Date of Patent: November 10, 1992Assignee: Hughes Aircraft CompanyInventors: Antonio C. Pastor, deceased, Luisa E. Gorre, deceased
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Patent number: 5152973Abstract: The invention process provides a metal oxide, or oxides of more than one more metal, wherein the oxides have a mean particle size less than 1 micron. The oxides are made by steps including (1) reacting an aqueous solution of a metal salt (or salts) that form insoluble carbonate(s), thereby to form a carbonate precipitate, followed by (b) recovering the precipitate, e.g., by filtration; (c) redispersing the precipitate in water to form a second very dilute slurry; (d) spray-drying said second slurry; (e) calcining the spray-dried product at a low temperature (e.g., 540.degree. C.), followed by a final calcination in atmosphere consisting of flowing oxygen initially under reduced pressure (e.g., 2 Torr). The spray-dried spheroids comprise particles having a mean particle size less than one micron, a property carried over into the products of both calcinations.Type: GrantFiled: May 8, 1990Date of Patent: October 6, 1992Assignee: W. R. Grace & Co.-Conn.Inventor: Nicholas D. Spencer
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Patent number: 5149682Abstract: Superior homogeneity in ceramic materials is achieved by reacting certain soluble metal salts with quaternary ammonium carbonates to form co-precipitated metal carbonates. The precipitate can be recovered and processed to make superconductors. For example, a solution of nitrates of yttrium, barium, and copper are treated with a solution of tetraethyl ammonium carbonate to form co-precipitated carbonates of Y, Ba, Cu. The precipitate is recovered and calcined to form a superconducting material.Type: GrantFiled: February 12, 1988Date of Patent: September 22, 1992Assignee: W. R. Grace & Co. -Conn.Inventors: Nicholas D. Spencer, Wie H. Pan, John Rudesill
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Patent number: 5147848Abstract: A process for preparing powder of high temperature oxide superconductors of Bi-Pb-Sr-Ca-Cu-O type. In an aqueous solution of nitrate salts of Bi, Pb, Sr, Ca, and Cu metals, an appropriate ratio of triethylamine/oxalic acid was added to form a coprecipitate. Through the process of calcination at a temperature in the range of 750.degree. C. to 800.degree. C. and sintering at a temperature of 860.degree. C., a uniform and fine powder superconductive metal oxide having a critical temperature of 110K is obtained as the final product.Type: GrantFiled: July 11, 1990Date of Patent: September 15, 1992Assignee: Industrial Technology Research InstituteInventors: Chau-Ting Chang, Cheng-Yei Shei, Ru-Shi Liu
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Patent number: 5135907Abstract: A method for the manufacture of superconducting polycrystalline ceramic materials by the decomposition of a mixture of isopropoxides.Type: GrantFiled: December 1, 1988Date of Patent: August 4, 1992Assignee: General AtomicsInventors: Khodabakhsh S. Mazdiyasni, Debra J. Treacy, Barry W. McQuillan, Frederick H. Elsner
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Patent number: 5122508Abstract: A process for preparing a bulk powder for an oxide superconductor which comprises mixing an alcohol solution (I) of a copper nitrate and a lanthanoid metal nitrate with an alcohol solution (II) comprising at least one compound selected from the group consisting of a barium hydroxide and a barium alkoxide to give a coprecipitate, and thermally decomposing the coprecipitate. According to the present invention, compared to the solid-state reaction, fine particles having the particle size of not more than 1 .mu.m can be easily produced because barium carbonate comparatively stable to heat is not formed on calcination, and the desired bulk powder for oxide superconductor can be produced at even lower temperature. Consequently, the obtained bulk powder for the oxide superconductor has fine particles, e.g. the particle size being not more than 1 .mu.m, therefore, the powder is excellent in stoichinometry, large in surface energy and excellent in sintering property.Type: GrantFiled: December 9, 1988Date of Patent: June 16, 1992Assignee: Kanegafuchi Kagaku Kogyo Kabushiki KaishaInventors: Tsutomu Nanao, Kenji Yamamoto, Masao Yokoyama
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Patent number: 5122510Abstract: A method of making high T.sub.c 1-2-3 superconductors having perovskite structure using solution techniques is disclosed. The process uses two solvent systems to form a resinous preceramic material having a controlled viscosity for facilitating its formation into superconducting articles such as fibers, wires, ribbons, films and the like. The process yields a pre-ceramic which is flexible and which has sufficient structural integrity to withstand normal handling.Type: GrantFiled: October 29, 1990Date of Patent: June 16, 1992Assignee: General AtomicsInventors: Kuo-Chun Chen, Khodabakhsh S. Mazdiyasni
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Patent number: 5114911Abstract: An oxalate route coprecipitation process for preparing a superconducting YBaCuO system precursor powder comprises preparing an aqueous solution of nitrates of yttrium, barium and copper, which is then mixed with an organic solution containing a dibasic oxalate ester, an organic base and acetone. An ultrasound vibration is applied to the mixture to coprecipitate oxalates of yttrium, barium and copper. The decomposition of the oxalate ester is enhanced to an optimum rate as the result of the homogeneous phase contributed by acetone which is miscible with both water and the oxalate ester. The ultrasound vibration segregates the precipitate particles thereby preventing the coagulation of the particles and assuring fine and uniform particle size.Type: GrantFiled: February 20, 1991Date of Patent: May 19, 1992Assignee: Industrail Technology Research InstituteInventors: Cheng-Yie Shei, Weir-Mirn Hurng, Chau-Ting Chang
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Patent number: 5100871Abstract: A method of making high T.sub.c 1-2-3 superconductors having perovskite structure using solution techniques is disclosed. The process uses two solvent system to form a resinous pre-ceramic material having a controlled viscosity for facilitating its formation into superconducting articles such as fibers, wires, ribbons, films and the like. The process yields a pre-ceramic which is flexible and which has sufficient structural integrity to withstand normal handling.Type: GrantFiled: November 28, 1989Date of Patent: March 31, 1992Assignee: General AtomicsInventors: Kuo-Chun Chen, Khodabakhsh S. Mazdiyasni
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Patent number: 5061683Abstract: There is disclosed an improved process for preparing a superconducting composition having the formula M.sub.w A.sub.z Cu.sub.v O.sub.x wherein M is selected from the group consisting if Bi, Tl, Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm Yb and Lu; A is at least one alkaline earth metal selected from the group consisting of Ba, Ca and Sr; x is at least 6; w is at least 1; z is at least 2 and v is at least 1; said composition having a superconducting transition temperature of above 77 K, preferably above about 90 K; said process consisting essentially of (a) forming a suspension having an M:A:Cu atomic ratio of w:z:v by mixing A(OH).sub.2, AO or AO.sub.2 and M.sub.2 O.sub.3 with an aqueous solution of cupric carboxylate or cupric nitrate at a temperature from about 50.degree. C. to about 100.degree. C., or mixing A(OH).sub.2 with an aqueous solution of Cu carboxylate, nitrate or a mixture thereof and M carboxylate, nitrate or a mixture thereof at a temperature from about 50.degree. C. to about 100.degree. C.Type: GrantFiled: May 31, 1988Date of Patent: October 29, 1991Assignee: E. I. Du Pont de Nemours and CompanyInventor: Harold S. Horowitz
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Patent number: 5028585Abstract: Two or more superconductors are reacted together to form a non-superconducting phase encapsulating a residual superconducting phase. For example YBa.sub.2 Cu.sub.3 oxide is reacted with Bi.sub.2 Sr.sub.2 CaCu.sub.2 oxide to form a superconducting product containing a novel non-superconducting oxide of Y, Bi, and Ba. A superconducting YBa.sub.2 Cu.sub.3 oxide remains as an interconnected phase throughout the product. The new non-superconducting phase largely encapsulates and insulates the superconducting phase.Type: GrantFiled: May 13, 1988Date of Patent: July 2, 1991Assignee: W. R. Grace & Co.-Conn.Inventor: Nicholas D. Spencer
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Patent number: 5023067Abstract: An extremely pure oxide containing two or more metals, homogeneous at the atomic level, is prepared by (1) reacting in water, soluble salts of two or more metals with quaternary ammonium carbonate; the metals being those that form water-insoluble carbonates, thereby to precipitate mixed carbonates of the metals; (2) recovering and drying the precipitate; (3) calcining the precipitate to provide an oxide of mixed metals homogeneous at the atomic level and substantially free from extraneous contaminants. The calcined oxide can be shaped and compressed as greenware and sintered to form useful ceramic products.Type: GrantFiled: August 26, 1988Date of Patent: June 11, 1991Assignee: W. R. Grace & Co.-Conn.Inventors: Nicholas D. Spencer, Wie-Hin Pan, John A. Rudesill
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Patent number: 5019555Abstract: The present invention is related to a composition and methods for producing highly pure, high temperature superconducting materials having the general formula MBa.sub.2 Cu.sub.3 O.sub.7-x, where M is yttrium or a rare earth element and x is from 0 to 0.5. The superconducting material is produced by first obtaining a solution of yttrium or rare earth element and copper. Next a solution of barium is obtained. The two solutions are heated and mixed together forming a precursor precipitate of the superconducting material. Subsequently, in one embodiment of the invention, the precipitate is recovered, calcined, sintered and slow cooled in oxygen or air. This produces a material having a desirable orthorhomic structure which is superconductive at high temperatures.Because no organic solvents are used and no pH control other than the amount of barium in the solution is employed, it is possible to provide a highly pure superconducting material.Type: GrantFiled: August 10, 1988Date of Patent: May 28, 1991Assignee: General AtomicsInventors: Jack Chin, Samuel S. Liang
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Patent number: 5011822Abstract: A method for producing uniform mixed metal oxides, such as superconducting mixtures including Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x, in which such metals are precipitated as their oxalates from alcoholic solutions of the metals as the salts of a carboxylic acid.Type: GrantFiled: January 10, 1989Date of Patent: April 30, 1991Assignee: Allied-Signal Inc.Inventor: Timothy J. Barder
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Patent number: 5002926Abstract: Improved process for making Tl-Ca-Ba-Cu oxide superconductors. A solution of the nitrated of Ca, Ba, and Cu is reacted with a quaternary ammonium carbonate in a slurry (heel) of Tl.sub.2 O.sub.3. Carbonates of Ca, Ba, and Cu precipitate homogeneously on the Tl.sub.2 O.sub.3 particles. Solids are recovered, dried, and heated to make a superconductor. The method minimizes introdution of contaminants. Novel compositions result.Type: GrantFiled: June 3, 1988Date of Patent: March 26, 1991Assignee: W. R. Grace & Co.- Conn.Inventors: Nicholas D. Spencer, Leonard E. Dolhert
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Patent number: 5001109Abstract: Improved process for making Bi-Pb-Sb-Sr-Ca-Cu oxide superconductors. A solution of the nitrates of Bi, Pb, Sr, Ca, and Cu is reacted with a quaternary ammonium carbonate in a dispersion (heel) of Sb.sub.2 O.sub.5. Carbonates of Bi, Pb, Sr, Ca, and Cu precipitate homogeneously on the Sb.sub.2 O.sub.5 particles. Solids are recovered, dried, and heated to make a superconductor. The method minimizes handling toxic antimony compounds and reduces introduction of contaminants. Novel compositions result.Type: GrantFiled: March 16, 1989Date of Patent: March 19, 1991Assignee: W. R. Grace & Co.-Conn.Inventor: Nicholas D. Spencer
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Patent number: 5001107Abstract: This invention provides improved methods for the preparation of precursor powders that are used in the preparation of superconducting ceramic materials that contain thallium. A first solution that contains the hydrogen peroxide and metal cations, other than thallium, that will be part of the ceramic is quickly mixed with a second solution that contains precipitating anions and thallium (I) to form a precipitate which is dried to yield precursor powders. The precursor powders are calcined an sintered to produce superconducting materials that contain thallium.Type: GrantFiled: August 2, 1989Date of Patent: March 19, 1991Assignee: The United States Department of EnergyInventors: Bruce C. Bunker, Diana L. Lamppa, James A. Voigt
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Patent number: 4975415Abstract: The present invention pertains to a method of preparing particles of superconducting ceramic powders, which method comprises:(a) dissolving the soluble salts of the cations in aqueous medium;(b) obtaining a solution having pH of between about 4 and 7 by optionally treating the aqueous medium with ammonia, or ammonium hydroxide;(c) atomizing the solution of step (b) onto liquid nitrogen at about -196.degree. C.;(d) removing the liquid nitrogen by evaporation;(e) removing the water by sublimation at reduced pressure;(f) heating the solid residue of step (e) at 40-60.degree. C. at reduced pressure;(g) calcining the solid residue in flowing oxygen or air at temperature of between about 200.degree. to 895.degree. C.; and(h) cooling the solid at a temperature of between about 900.degree. C. and ambient temperature in sufficient air or oxygen and recovering the superconducting powder having an average diameter of between about 0.1 and 10 microns.Type: GrantFiled: July 10, 1987Date of Patent: December 4, 1990Assignee: SRI - InternationalInventors: Michael I. Gusman, Sylvia M. Johnson
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Patent number: 4956340Abstract: 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.Type: GrantFiled: November 3, 1989Date of Patent: September 11, 1990Assignee: Mitsubishi Kinzoku Kabsuhiki KaishaInventors: Etsuji Kimura, Nozomu Hasegawa, Yutaka Nishiyama
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Patent number: 4904638Abstract: A process is disclosed for producing a homogeneous mixture of co-precipitated carbonate salts capable of reacting together in an oxygen atmosphere at an elevated temperature to form a superconducting ceramic which comprises forming a first solution by dissolving in a first solvent maintained at a temperature of from about 15.degree. to 35.degree. C. a rare earth compound, an alkaline earth metal compound, and a copper compound capable of reacting with a carbonate ion to form an insoluble precipitate of carbonate salts in the solvent used to form the solution; forming a second solution containing a carbonate-forming compound dissolved in a second solvent miscible with the first solvent; blending the first and second solutions together at a temperature of from about 0.degree. to 15.degree. C.Type: GrantFiled: March 3, 1988Date of Patent: February 27, 1990Assignee: Hewlett-Packard CompanyInventor: Stephen A. DiCarolis
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Patent number: 4895832Abstract: A homogenous coprecipitation method by which superconducting oxides having perovskite-like structure, such as YBa2Cu307-x, can be produced in mass, in which urea is used as solvent to adjust and control the PH value of an aqueous nitrate solution. The coprecipitation method of this invention comprises following steps: (a) preparing an aqueous mixture containing Y, Ba and Cu salts with molar ratio of 1:2:3 wherein Y being 0.068M; (b) adding 5-10 moles of oxalic acid per one mole of Y and 20-250 moles of urea per moles of Y into the aqueous mixture; (c) heating the aqueous mixture to a temperature range of 80.degree. to 100.degree. C. to proceed a hydrolysis of the urea such that PH value of the aqueous mixture will be gradually elevated by NH.sub.3 gas evoluted from the urea hydrolysis; and (d) cooling the temperature of the aqueous mixture to room temperature at which time a desired uniform PH value is reached. After cooling, pale blue homogeneous coprecipitates of the superconducting oxides can be obtained.Type: GrantFiled: November 3, 1988Date of Patent: January 23, 1990Assignee: Industrial Technology Research InstituteInventors: Chau-Ting Chang, Ru-Shi Liu