By Sol-gel Process Patents (Class 505/735)
  • Patent number: 11854717
    Abstract: The present disclosure relates to a method for preparing high-temperature superconducting yttrium barium copper oxide (YBCO) wire by 3D-printing, this method is divided into the following four steps: firstly, preparing a nano-level superconducting powder precursor; and then, preparing a printing paste with suitable viscosity and supporting characteristics; after that, using a CAD 3D modeling, exporting STL format model data and slicing by a professional software; implementing one-step preparing strands with low AC loss by twisting the print nozzle. Finally, the printed twisted wire is formed into a practical superconducting twisted cable through the processes such as plastic removal process, crystallizing process, oxygen supplementing process and assembling process in order. The present disclosure firstly provides an application for applying high temperature superconducting material to direct ink writing 3D-printing technology.
    Type: Grant
    Filed: September 15, 2020
    Date of Patent: December 26, 2023
    Assignee: LANZHOU UNIVERSITY
    Inventors: Xingyi Zhang, Baoqiang Zhang, Qiangqiang Zhang, Cong Liu, Huadong Yong, Youhe Zhou
  • Patent number: 6616965
    Abstract: Tantalum and niobium aluminum-doped hydrated mixed metal oxide sols may be made by a process comprising combining a first metal compound aluminum alkoxide, with a second metal compound selected from the group consisting of niobium alkoxide and tantalum alkoxide, and mixtures thereof to provide a substantially water-free precursor and combining the precursor with a ketone to provide a hydrated mixed metal oxide sol, wherein the ketone is substantially free of water. The sol may then be processed to obtain thin films, fibers, crystals (both micro- and meso-porous), powders and macroscopic objects and to provide mixed metal oxide that may be used in a variety of components of integrated circuits.
    Type: Grant
    Filed: March 23, 2000
    Date of Patent: September 9, 2003
    Assignee: Agere Systems Inc.
    Inventors: Sudhanshu Misra, Pradip Kumar Roy
  • Patent number: 6559103
    Abstract: A process is provided for preparing solid superconducting mixed-metal oxides whereby the superconductor can be formed into any predetermined shape by way of viscous sol precursors. The superconductors are also formed by this process into homogeneous phases.
    Type: Grant
    Filed: March 17, 1989
    Date of Patent: May 6, 2003
    Assignee: The Boeing Company
    Inventors: Brad Lee Kirkwood, Thomas S. Luhman, Ronald Roy Stephenson, Michael Strasik
  • Publication number: 20020115307
    Abstract: A method for manufacturing a ferroelectric thin film using a sol-gel process comprising the steps of dissolving a Pb precursor using a solvent to prepare a Pb solution and stabilizing a Zr precursor and a Ti precursor to prepare a Zr solution and a Ti solution, respectively, mixing the Zr solution and Ti solution, stirring the Ti-Zr mixed solution with the Pb solution and hydrolyzing to prepare a ferroelectric solution, and forming a ferroelectric thin film on a substrate using the ferroelectric solution.
    Type: Application
    Filed: December 28, 2001
    Publication date: August 22, 2002
    Inventors: Yong-Kyun Lee, June-Key Lee
  • Patent number: 5620945
    Abstract: Processes are provided for forming a superconductive composite, comprising a superconductive metal oxide and a ceramic. The composite may be formed in any desired shape. Liquid nitrogen can be held around the superconductor longer and delivered in a more controlled fashion and the composite has improved resistance to shatter and thermal shock. The ceramic also provides protection from atmospheric deterioration of the superconductive oxide.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: April 15, 1997
    Assignee: The Boeing Company
    Inventors: Anna L. Baker, Michael Strasik
  • Patent number: 5589441
    Abstract: Processes are provided for forming a superconductive composite, comprising a superconductive metal oxide and a ceramic. The composite may be formed in any desired shape. Liquid nitrogen can be held around the superconductor longer and delivered in a more controlled fashion and the composite has improved resistance to shatter and thermal shock. The ceramic also provides protection from atmospheric deterioration of the superconductive oxide.
    Type: Grant
    Filed: August 19, 1994
    Date of Patent: December 31, 1996
    Assignee: The Boeing Company
    Inventors: Anna L. Baker, Michael Strasik
  • Patent number: 5480862
    Abstract: Method for the preparation of a precursor for a superconductor, comprising the addition of a condensation product to an aqueous solution of metal salts, the total or partial removal of water from the mixture thus obtained, the subsequent processing of the viscous mass obtained after having removed part of the water or the calcination of the solid gel obtained after having substantially removed all the water, wherein the condensation product is a product of esterification of citric acid with ethylene glycol prepared separately and the solution of metal salts substantially is a solution of acetates in water and acetic acid.
    Type: Grant
    Filed: July 30, 1993
    Date of Patent: January 2, 1996
    Assignee: Pirelli Cavi S.p.A.
    Inventor: Giorgio S. Miszenti
  • Patent number: 5368768
    Abstract: Solubilized metal (dialkylaminoalcoholate) compounds in organic solvent can serve as a source of metal values for metal oxide-containing superconductor compositions. Stable solutions, resistant to precipitation problems, can be formed by reaction of a dialkylaminoalkanol with a metal alkoxide followed by removal of by-product alkanol by vacuum distillation below the reflux temperature of the solution. Exemplary metals include copper, yttrium, barium, calcium, and bismuth, lanthanum and strontium.
    Type: Grant
    Filed: May 24, 1993
    Date of Patent: November 29, 1994
    Assignee: Akzo Nobel Inc.
    Inventors: Carl C. Greco, Johst H. Burk
  • Patent number: 5306696
    Abstract: A method of producing a superconductor of metal oxides having the following composition:(M.sub.1-x Ca.sub.x)(Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.4 O.sub.8wherein M stands for a rare earth element, x is 0 or a positive number of less than 1 and y is 0 or a positive number of less than 1, is disclosed, which includes hydrdolyzing an organic solvent solution or dispersion containing (a) alkoxide or fine particulate of a hydroxide of the rare earth element M, (b) alkoxides orfine particulate of hydroxides of Ca, Ba and Sr and (c) alkoxide, nitrate or fine particulate of hydroxide of copper in presence of water and nitrate ions. The alkoxides or hydroxides of Ca and Sr are present only when x and y are not zero, respectively. The hydrolyzed product is then dried, shaped and pyrolyzed to obtain the superconductor.
    Type: Grant
    Filed: December 10, 1990
    Date of Patent: April 26, 1994
    Assignees: Kabushiki-Gaisha Arubakku Kohporehiosentah, Nippon Mining Co., Ltd., Ishikawajima-Harima Jukogyo Kabushiki Kaisha, International Superconductivity Technology Center
    Inventors: Hirohiko Murakami, Junya Nishino, Seiji Yaegashi, Yu Shiohara, Shoji Tanaka
  • Patent number: 5304533
    Abstract: A process for producing a superconductor of an oxide system, which comprises uniformly mixing metal elements for constituting the oxide system at least partly in the form of alkoxides having CN.sup.--, X.sup.-- wherein A is a halogen atom and/or an amine, with the rest, if any, being in the form of acetylacetonates, carboxylates and/or water-soluble inorganic compounds to obtain a homogeneous mixture, and sintering the mixture.
    Type: Grant
    Filed: August 24, 1988
    Date of Patent: April 19, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshio Kobayashi, Fusaoki Uchikawa, Kenji Nomura, Fumio Fujiwara, Sigeru Matsuno, Masao Morita, Shouichi Yokoyama
  • Patent number: 5294599
    Abstract: Fine and homogeneous oxide particles for superconductors which can be sintered at a low temperature are prepared in a liquid phase by the sol-gel method using alkoxides as starting materials. By forming a buffer layer between a substrate and a superconducting film, good-quality and oriented superconducting film can be fabricated. Highly c-axis-oriented superconducting film and bulk products can be prepared from particular starting compositions in Ln-Ae-Cu-O and Bi-Ae-Cu-O systems. The oriented film can be produced by painting a paste of such starting compositions on a substrate followed by sintering, and the bulk form can be produced by pressing the pre-sintered powder of such starting compositions.
    Type: Grant
    Filed: February 15, 1989
    Date of Patent: March 15, 1994
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Shuichi Shibata, Takeshi Kitagawa, Hisaaki Okazaki, Takao Kimura, Masaharu Horiguchi
  • Patent number: 5236890
    Abstract: A method of producing a superconductor of metal oxides which includes subjecting an organic solvent solution containing (a) an alkoxide of a rare earth element, (b) an alkoxide of an alkaline earth metal and (c) copper alkoxide or cupric nitrate to hydrolysis in the presence of water and nitrate ions, thereby forming a mixture containing a gel-like substance. The gel-like substance is, after being dried and formed into a desired shape, pyrolyzed at a temperature of 600.degree.-950.degree.C. to form a superconductor of oxides of the rare earth, the alkaline earth metal and copper.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: August 17, 1993
    Assignees: Kabushiki-Gaisha Arubakku Kohporehtosentah, Nippon Mining Co., Ltd., Ishikawajima-Harima Jukogyo Kabushiki Kaisha, The International Superconductivity Technology Center
    Inventors: Hirohiko Murakami, Junya Nishino, Seiji Yaegashi, Yu Shiohara, Shoji Tanaka
  • Patent number: 5232909
    Abstract: A superconducting ceramics elongated body comprising a flexible ceramics elongated substrate and an oxide ceramics superconducting layer formed at least on a part of the surface of the ceramics elongated substrate to longitudinally extend along the ceramics elongated substrate. The superconducting ceramics elongated body further comprises a protective layer of ceramics containing a nitride, which is provided to at least cover the surface of the superconducting layer exposed on the ceramics elongated substrate. A method of manufacturing a superconducting ceramics elongated body by forming a longitudinally continuous superconducting layer on at least a part of the surface of a flexible ceramics elongated substrate. The superconducting layer is formed on the elongated substrate by a sol-gel method, a coating/sintering method, evaporation under oxygen ions, deposition from a fluoride solution or oxidation after application of corresponding fluorides.
    Type: Grant
    Filed: May 8, 1992
    Date of Patent: August 3, 1993
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Satoshi Takano, Kenichi Takahashi, Kenji Miyazaki, Noriyuki Yoshida, Shinji Inazawa, Noriki Hayashi
  • Patent number: 5229359
    Abstract: Solutions containing the cations of the metals Y, Ba, Cu in the atomic ratio 1:2:3 or the cations of the metals Bi, Sr, Ca and Cu having the atomic ratios of a high-temperature superconductor bound to polyacrylic acid in water as dispersant and having a viscosity of 150-10,000 cSt (at 20.degree. C.) serve to produce superconducting filaments or coatings.To produce a superconducting filament, a solution is forced through a nozzle and the extruded filamentous strand is left to solidify in an organic solvent which is miscible with water, the filament is isolated, dried and heated to at least 800.degree. C. in the presence of oxygen, annealed at at least 800.degree. C. for at least one hour in the presence of oxygen and then cooled.
    Type: Grant
    Filed: May 3, 1991
    Date of Patent: July 20, 1993
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Winfried Becker
  • Patent number: 5229335
    Abstract: The invention provides a process for producing high phase purity ceramic materials through the utilization of organic gelling agents. The process comprises the following steps: (a) dissolving stoichiometric amounts of metal salts in a solvent to form a solution; (b) heating the solution to a temperature sufficient to dissolve the gelling agent; (c) dissolving from about 0.1 to about 50 weight percent of an organic gelling agent into the heated solution; (d) cooling the solution to form a gel; (e) drying the gel to form a xerogel precursor; and (f) subjecting the xerogel precursor to a calcination process to produce a high phase purity ceramic material.
    Type: Grant
    Filed: November 1, 1991
    Date of Patent: July 20, 1993
    Assignee: Temple University - of the Commonwealth System of Higher Education
    Inventors: Robert E. Salomon, Jorge J. Macho
  • Patent number: 5210069
    Abstract: A preparation method for high-purity Tl-based superconductor phase of 115 K, and the precursor thereof. The process comprises a specific composition of precursors, represented by the formula:(Tl.sub.a Pb.sub.b Bi.sub.c)Sr.sub.2-x Ca.sub.2+x Cu.sub.y O.sub.z, wherein (a+b+c)=1, 0<x.ltoreq.1 and 2.ltoreq.y.ltoreq.4, for the manufacturing of Tl-based superconductor by adding oxalic acid as a chelating agent which equals to half the molar amount of total nitrate anions in the required metal nitrates aqueous solution and adjusting pH value of the solution to obtain the superconductor.
    Type: Grant
    Filed: October 16, 1991
    Date of Patent: May 11, 1993
    Assignee: Industrial Technology Research Institute
    Inventors: Chung-Kwang Chiang, Cheng-Yie Shei
  • Patent number: 5153172
    Type: Grant
    Filed: October 1, 1990
    Date of Patent: October 6, 1992
    Assignee: General Atomics
    Inventors: Kuo-Chun Chen, Khodabakhsh S. Mazdiyasni
  • Patent number: 5142074
    Abstract: The invention relates to the preparation of high purity, chloride- and alkali metal-free copper (II) alkoxides by means of the reaction of an alcoholic alkali metal alkoxide solution with copper (II) fluoride; ammoniating the resulting solution to render soluble the resulting copper (II) alkoxide; and filtering the resulting solution to obtain an alkali metal- and chloride-free alcoholic copper (II) alkoxide solution. The resulting solution is useful in the preparation of superconducting compound such as yttrium-barium-copper oxide superconductor.
    Type: Grant
    Filed: April 19, 1991
    Date of Patent: August 25, 1992
    Assignee: General Atomics
    Inventors: Debra J. Treacy, Khodabakhsh S. Mazdiyasni
  • Patent number: 5135907
    Abstract: A method for the manufacture of superconducting polycrystalline ceramic materials by the decomposition of a mixture of isopropoxides.
    Type: Grant
    Filed: December 1, 1988
    Date of Patent: August 4, 1992
    Assignee: General Atomics
    Inventors: Khodabakhsh S. Mazdiyasni, Debra J. Treacy, Barry W. McQuillan, Frederick H. Elsner
  • Patent number: 5122510
    Abstract: 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: Grant
    Filed: October 29, 1990
    Date of Patent: June 16, 1992
    Assignee: General Atomics
    Inventors: Kuo-Chun Chen, Khodabakhsh S. Mazdiyasni
  • Patent number: 5106828
    Abstract: Superconducting oxides in the A, B, Cu oxide ternary system, where A is yttrium or a rare earth and B is an alkaline earth, are formed as thin films on a substrate by a sol-gel technique.
    Type: Grant
    Filed: July 20, 1987
    Date of Patent: April 21, 1992
    Assignee: North American Philips Corporation
    Inventors: Rameshwar N. Bhargava, William N. Osborne, Walter K. Zwicker
  • Patent number: 5100871
    Abstract: 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: Grant
    Filed: November 28, 1989
    Date of Patent: March 31, 1992
    Assignee: General Atomics
    Inventors: Kuo-Chun Chen, Khodabakhsh S. Mazdiyasni
  • Patent number: 5087609
    Abstract: A process for forming an alkoxide-derived yttrium-barium-copper oxide high temperature superconductor thin film by sol-gel processing is disclosed. It comprises first forming a thin film comprising solubilized yttrium and barium alkoxides and copper aminoalkoxide, under an inert gas atmosphere, on a non-reactive substrate, the amount of copper amino alkoxide being in excess of the stoichiometric amount to compensate for losses due to volatility of the copper amino alkoxide. The coating composition is then heated first in a moisture laden inert gas atmosphere, to hydrolyze the alkoxides, to temperatures in excess of the formation temperature of the superconductor. It is thereafter calcined in an oxygen atmosphere at higher temperatures to form the high temperature superconductor thin film.
    Type: Grant
    Filed: September 24, 1990
    Date of Patent: February 11, 1992
    Assignee: Akzo NV
    Inventors: George E. Whitwell, Meiylin F. Antezzo
  • Patent number: 5071830
    Abstract: An epitaxial thallium-based copper oxide superconducting film is formed on a crystalline substrate by metalorganic deposition which comprises forming a film of carboxylate soap solution on said substrate, prepyrolyzing said film at a temperature of 350.degree. C. or less and pyrolyzing said film at a temperature of 800.degree.900.degree. C. in the presence of oxygen and an overpressure of thallium for a sufficient time to produce said epitaxial superconducting film.
    Type: Grant
    Filed: August 31, 1988
    Date of Patent: December 10, 1991
    Assignee: Superconductor Technologies, Inc.
    Inventors: William L. Olson, Michael M. Eddy, Robert B. Hammond, Timothy W. James, McDonald Robinson
  • Patent number: 5071829
    Abstract: This invention describes the way to prepare high purity Bi-based superconducting powders with the zero resistance temperature at 110K. The technique employs the dissolution of corresponding metal nitrates in deionized water, plus oxalic acid to chelate the metal cations. The amount of oxalic acid equals to about half of the total nitrate anion in molar ratio. After pH adjustment and gelation, optimal calcination results in 110K superconducting powders in high purity.
    Type: Grant
    Filed: June 27, 1990
    Date of Patent: December 10, 1991
    Assignee: Industrial Technology Research Institute
    Inventors: Chung K. Chiang, Cheng Y. Shei, Yao T. Huang
  • Patent number: 5066636
    Abstract: A citrate/ethylenediamine gel method for forming oxide superconductors of the Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O, Tl-Ca-Ba-Cu-O system by employing the nitrates of the individual metals and citric acid. Ethylenediamine is then added to form gels. These materials then undergo calcination and sintering processes. The respective superconductors obtained possess a superconducting zero resistance temperature at 93K, 78K and 118K respectively.
    Type: Grant
    Filed: August 15, 1990
    Date of Patent: November 19, 1991
    Assignee: Industrial Technology Research Institute
    Inventors: Ru-Shi Liu, Wang-Nang Wang, Chan-Ting Chang
  • Patent number: 5026684
    Abstract: A method is disclosed for preparation of superconductive substances, and in particular, those comprising a rar earth element, barium (Ba), copper (Cu) and oxygen, having a composition represented by the general formula: LnBa.sub.2 Cu.sub.3 O.sub.7-.delta. in which Ln represents a rare earth element and .delta. has a value of about 0 to 0.5. The method includes forming a solution containing an organic compound of a rear earth element, an organic barium compound and an organic copper compound in an organic solvent, homogenizing the resulting solution, stripping the organic solvent from the homogenized solution by evaporation to give a precipitate and pyrolyzing the precipitate to obtain the superconductive substance. The precipitate may also be formed as fibers or films prior to pyrolysis.
    Type: Grant
    Filed: April 12, 1989
    Date of Patent: June 25, 1991
    Assignees: Dow Corning Corporation, Shin-Ichi Hirano
    Inventors: Ronald H. Baney, Shin-ichi Hirano
  • Patent number: 5011796
    Abstract: A sol-gel method is disclosed for the production of polycrystalline strontium barium niobate (SBN) materials. Ceramic SBN materials produced in accordance with this method possess favorable ferroelectric properties, and are useful for electro-optic applications.
    Type: Grant
    Filed: October 23, 1989
    Date of Patent: April 30, 1991
    Assignee: Martin Marietta Corporation
    Inventors: Keith Bridger, Lorianne Jones, Stephen R. Winzer
  • Patent number: 5006508
    Abstract: The invention relates to the preparation of high purity, chloride- and alkali metal-free copper (II) alkoxides by means of the reaction of an alcoholic alkali metal alkoxide solution with copper (II) fluoride; ammoniating the resulting solution to render soluble the resulting copper (II) alkoxide; and filtering the resulting solution to obtain an alkali metal- and chloride-free alcoholic copper (II) alkoxide solution. The resulting solution is useful in the preparation of superconducting compound such as yttrium-barium-copper oxide superconductor.
    Type: Grant
    Filed: February 3, 1989
    Date of Patent: April 9, 1991
    Assignee: General Atomics
    Inventors: Debra J. Treacy, Khodabakhsh S. Mazdiyasni
  • Patent number: 5004720
    Abstract: A process for producing a superconductor of an oxide system, which comprises uniformly mixing metal elements for constituting the oxide system at least partly in the form of acetylacetonates in a solvent with the rest, if any, being in the form of alkoxides, carboxylates and/or inorganic salts, hydroxides and/or oxides to obtain a homogeneous mixture, and sintering the mixture.
    Type: Grant
    Filed: August 24, 1988
    Date of Patent: April 2, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshio Kobayashi, Fusaoki Uchikawa, Kenji Nomura, Masao Morita, Shouichi Yokoyama
  • Patent number: 5001110
    Abstract: A solution for forming a superconductive thin film prepared by dissolving a mol of a compound selected from group A consisting of alkoxides and alkoxyalkoxides of a rare earth metal element; b mol of a compound selected from group B consisting of alkoxides and alkoxyalkoxides of Ba, Sr and Ca; and c mol of a compound selected from group C consisting of alkoxides and alkoxyalkoxides of Cu in e liter of a compound selected from group E, a solvent selected from alcohols together with d mol of a compound selected from group D for inhibiting hydrolysis action such as an amine, a ketone and a glycol, such that the following relationships:0.1.times.(a+b+c).ltoreq.d.ltoreq.3.times.(a+b+c)and0.01.ltoreq.[(a+b+c)/e].ltoreq.3can be satisfied.
    Type: Grant
    Filed: July 14, 1989
    Date of Patent: March 19, 1991
    Assignee: Toray Industries, Inc.
    Inventors: Toshihisa Nonaka, Keisuke Kobayashi, Hiroyuki Igaki, Michiyasu Matsuki
  • Patent number: 4977109
    Abstract: This invention provides a process for the preparation of the precursor used in the fabrication of Y--Ba--Cu--O superconductors. This process mainly uses solgel technology via the nitrate route by using a dicarboxylic acid. Among the dicarboxylic acids, oxalic acid is the best for preparing the precursor which can be fabricated into a good superconductor.
    Type: Grant
    Filed: July 27, 1988
    Date of Patent: December 11, 1990
    Assignee: Industrial Technology Research Institute
    Inventor: Ru-Shi Liu
  • Patent number: 4962082
    Abstract: Techniques for the preparation of superconducting perovskites in the MBa.sub.2 Cu.sub.3 O.sub.7-y system wherein M represents yttrium of a rare earth element and y is an integer ranging from 0.1 to 0.8 are described. The techniques involve the use of either a sol-gel or controlled precipitation process in which a barium solution in acetic acid is reacted with copper acetate and either a rare earth hydroxide or rare earth nitrate to form a colloid which is subsequently heated and fired to yield the desired composition. In the embodiment in which the nitrate is employed, the resultant colloid is freeze dried. In both the sol-gel and controlled precipitation processes, heating and firing are required to yield the desired characteristics.
    Type: Grant
    Filed: November 19, 1987
    Date of Patent: October 9, 1990
    Assignee: Bell Communications Research, Inc.
    Inventors: Philippe Barboux, Jean-Marie Tarascon
  • Patent number: 4959347
    Abstract: A process for producing a superconductor of an oxide system, which comprises uniformly dissolving, dispersing or suspending in a solvent metal elements for constituting the oxide system at least partly in the form of carboxylates with the rest, if any, being in the form of alkoxides, acetylacetonates and/or inorganic compounds, followed by removal of the solvent to obtain a homogeneous mixture, and sintering the mixture.
    Type: Grant
    Filed: August 24, 1988
    Date of Patent: September 25, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshio Kobayashi, Fusaoki Uchikawa, Kenji Nomura
  • Patent number: 4956340
    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.
    Type: Grant
    Filed: November 3, 1989
    Date of Patent: September 11, 1990
    Assignee: Mitsubishi Kinzoku Kabsuhiki Kaisha
    Inventors: Etsuji Kimura, Nozomu Hasegawa, Yutaka Nishiyama