Containing Three Atoms Of Copper To Between Six And Seven Atoms Of Oxygen [e.g., Ycu3o(7-@), Lacu3o(6+*), Etc.] Patents (Class 505/126)
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Patent number: 5849668Abstract: An oxide superconductor which exhibits an uniform and high critical current density. Further, a method of manufacturing this oxide superconductor, namely, a RE--Ba--Cu--O oxide superconductor (RE is one or more kinds of rare earth elements including Y) by performing a treatment, which includes at least a burning process to be performed in a range of temperatures that are higher than a melting point of a raw material mixture containing a RE-compound raw material, Ba-compound raw material and a Cu-compound raw material, on the raw material mixture. This method further comprises a step of crushing the raw material mixture into particles and establishing the mean particle diameter of one or all of the raw materials as ranging from 50 to 80 .mu.m.Type: GrantFiled: June 18, 1997Date of Patent: December 15, 1998Assignee: Dowa Mining Co., Ltd.Inventors: Kazuya Yamaguchi, Shuichi Kohayashi, Shuetsu Haseyama, Shuji Yoshizawa
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Patent number: 5814585Abstract: The invention relates to a spray pyrolytic process for the preparation of multi-element metal oxide powders useful as precursors of high temperature superconductor ceramics. Aerosols of aqueous solutions containing corresponding metal salts admixed in the required stoichiometric proportion are sprayed through an independently operated hydrogen/oxygen flame in such a way that a flame temperature of 800.degree.-1100.degree. C. is maintained to form said powders. Any contact of the aerosols and powders generated during the process with carbon or carbon-containing compounds or materials is strictly avoided.Type: GrantFiled: November 26, 1996Date of Patent: September 29, 1998Assignee: Merck Patent Gesellschaft mit Beschrankter HaftungInventors: Rodney Riddle, Matthias Kuntz, Bernd Muller, Dietmar Raulin, Gunther Feldmann-Schlobohm
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Patent number: 5776862Abstract: The hole density of an oxide superconductor having holes as carriers is higher than the hole density to bring the highest value of the superconductivity critical temperature Tc thereof, and it can be made higher than the optimal density to bring the highest Tc value by treating the oxide superconductor with heat in an oxidizing gas atmosphere, or by replacing positive ions constituting the oxide superconductor except for copper with ions of a low valence number. Accordingly, it is possible to substantially reduce the rate of decrease of the critical current density owing to an applied magnetic field when the magnetic field is applied parallel to the crystal c axis, and to allow a current conductor produced by using the oxide superconductor to have high critical current density.Type: GrantFiled: July 22, 1996Date of Patent: July 7, 1998Assignees: Mitsubishi Denki Kabushiki Kaisha, Tohoku Electric Power Company, Incorporated, Toshiba Corporation, International Superconductivity Technology CenterInventors: Ryo Usami, Kazuyuki Isawa, Hiroshi Kubota, Roman Puzniak, Hisao Yamauchi, Shoji Tanaka
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Patent number: 5705457Abstract: The present invention provides an oxide superconductor which is expressed in the composition formula(Pb.sub.1-x-y M.sub.x (A1).sub.y)(A2).sub.2 (A3).sub.n-1 (Cu).sub.n (O).sub.2n+3+z(wherein 0.ltoreq.0.6, 0.ltoreq.y.ltoreq.0.6, x+y.ltoreq.0.6, n denotes integers of 1 or more, -0.6.ltoreq.z.ltoreq.0.5, M denotes Cu or Cd, and A1, A2 and A3 denote at least one element of Ba, Sr, and Ca, respectively) and which has a crystal structure stacking rock salt structure based portions and infinite layer structure portions, wherein the rock salt structure based portion has a structure that an atoms layer having 0.5-1.5 oxygen atoms, in case the total atoms number of Pb, M and A1 is one, and an atoms layer having one or less oxygen atoms per one A2 atom, are stacked and the infinite layer structure portion has a structure that an atoms layer having 2 oxygen atoms per one Cu atom and an atoms layer of A3 atoms only, are stacked.Type: GrantFiled: September 8, 1995Date of Patent: January 6, 1998Assignees: The Furukawa Electric Co., Ltd., Matsushita Electric Industrial Co., Ltd., International Superconductivity Technology CenterInventors: Toshiyuki Tamura, Seiji Adachi, Xiao-Jing Wu, Hisao Yamauchi
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Patent number: 5674815Abstract: An oxide superconductor composed of Cu, O and M (M is Ba, Sr and/or Ca) and including alternately arranged at least one rock-salt structure section and at least one infinite layer structure section, wherein the rock-salt structure section consists of two atomic layers each consisting of O and M and each having an atomic ratio O/M of 1 or less, and the infinite layer structure section consists of alternately arranged, first and second atomic layers. Each of the first atomic layers consists of O and Cu and has an atomic ratio O/Cu of 2, while each of the second atomic layers consists of the element M. The infinite layer structure section may consist of only one first atomic layer.Type: GrantFiled: March 6, 1996Date of Patent: October 7, 1997Assignees: International Superconductivity Technology Center, Matsushita Electric Industrial Co., Ltd.Inventors: Seiji Adachi, Hisao Yamauchi, Shoji Tanaka, Nobuo Mouri
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Patent number: 5650376Abstract: A superconducting film is disclosed which has the following composition:(Nd, Ba).sub.3 Cu.sub.3 O.sub.7-dwhere d is a number greater than 0 but smaller than 0.5. The superconducting film has the same crystal structure as that of YBa.sub.2 Cu.sub.3 O.sub.7 except that part of the Nd sites and/or part of the Ba sites are occupied by Ba and Nd atoms, respectively.Type: GrantFiled: November 6, 1995Date of Patent: July 22, 1997Assignee: International Superconductivity Technology CenterInventors: Massoud Badaye, Tadataka Morishita, Youichi Enomoto, Shoji Tanaka
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Patent number: 5648319Abstract: Disclosed is an oxide superconductor comprising an oxide of RE, Ba and Cu, which consists of a superconductor having a texture wherein the crystal directions of the 123 phase in the matrix are uniform, large angle grain boundaries having an directional difference larger than 20.degree. are not present and the 211 phase is finely dispersed, or an aggregate thereof, wherein the superconductor is formed into a plate or wire and the c-axis of the crystal of the formed body is uniform within .+-.30.degree. to the normal of the plate face of the formed body or in the range of from 60.degree. to 120.degree. to said normal. Also disclosed is a process for the preparation of an oxide superconductor as set forth above, which comprises inserting a formed body as mentioned above to a heating furnace and moving a region of a temperature at which grains are formed in the 123 phase of the matrix of the formed body, i.e., through a region having a temperature of from 1050.degree. to 910.degree. C.Type: GrantFiled: June 29, 1995Date of Patent: July 15, 1997Assignee: Nippon Steel CorporationInventors: Mitsuru Morita, Katsuyoshi Miyamoto, Kiyoshi Sawano, Shouichi Matsuda
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Patent number: 5620945Abstract: 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: GrantFiled: June 5, 1995Date of Patent: April 15, 1997Assignee: The Boeing CompanyInventors: Anna L. Baker, Michael Strasik
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Patent number: 5614472Abstract: The invention relates to a spray pyrolyric process for the preparation of multi-element metal oxide powders useful as precursors of high temperature superconductor ceramics. Aerosols of aqueous solutions containing corresponding metal salts admixed in the required stoichiometric proportion are sprayed through an independently operated hydrogen/oxygen flame in such a way that a flame temperature of 800.degree.-1100.degree. C. is maintained to form said powders. Any contact of the aerosols and powders generated during the process with carbon or carbon-containing compounds or materials is strictly avoided.Type: GrantFiled: May 12, 1995Date of Patent: March 25, 1997Assignee: Merck Patent Gesellschaft Mit Beschrankter HaftungInventors: Rodney Riddle, Matthias Kuntz, Bernd M uller, Dietmar Raulin, G unther Feldmann-Schlobohm
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Patent number: 5614471Abstract: A superconductive material is in composition expressed as Y.sub.0.33 Ba.sub.0.67).sub.a Cu.sub.b (OF).sub.c. The usual a, b and c are so selected as to satisfy a relation expression ax (mix valence of A)+bx (mix valence of B)=cx (mix valence of C).Type: GrantFiled: May 25, 1995Date of Patent: March 25, 1997Assignee: Sumitomo Electric Industries, Ltd.Inventors: Kengo Ohkura, Hajime Hitotsuyanagi, Hiromi Takei
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Patent number: 5589441Abstract: 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: GrantFiled: August 19, 1994Date of Patent: December 31, 1996Assignee: The Boeing CompanyInventors: Anna L. Baker, Michael Strasik
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Patent number: 5583093Abstract: Provided is a metal oxide material represented by the composition formula of Ln.sub.a Sr.sub.b Cu.sub.3-x M.sub.x O.sub.c, where 2.7.ltoreq.a+b.ltoreq.3.3; 0.8 .ltoreq.a.ltoreq.1.2; 6.ltoreq.c.ltoreq.9; and 0.05 .ltoreq.x.ltoreq.0.7, Ln is at least one element selected from the group of elements of Y and lanthanoids or an atomic group consisting of said elements, and M is at least one element selected from the group of elements of Ti, V, Ga, Ge, Mo, W and Re or an atomic group consisting of said elements.Type: GrantFiled: June 7, 1995Date of Patent: December 10, 1996Assignee: Canon Kabushiki KaishaInventors: Tohru Den, Tamaki Kobayashi
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Patent number: 5578551Abstract: The present invention is a controlled vapor/solid reaction process for the synthesis of samples of bulk compositions with a structure defined by the homologous series HgBa.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+2+.delta. [Hg-12(n-1)n] with n=2, 3, . . . with up to 75 to 90% Hg-1212 and 65 to 75% Hg-1223 by volume, which display sharp superconducting transitions up to 135 K.Type: GrantFiled: July 28, 1993Date of Patent: November 26, 1996Assignee: University of HoustonInventors: Ching-Wu Chu, Ruling Meng, Y. Q. Wang
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Patent number: 5571776Abstract: Enlargement of a crystal of a bulk oxide superconductor of REBa.sub.2 Cu.sub.3 O.sub.7-x, wherein RE is at least one of Y and rare earth elements, is effected by three dimensionally arranging layers of REBa.sub.2 Cu.sub.3 O.sub.7-x with a different RE in the order of decreasing (123) phase formation temperatures from the center outward, or by forming a stack of layers of RE Ba.sub.2 Cu.sub.3 O.sub.7-x with a different RE in the order of decreasing (123) phase formation temperatures; the size of the layer being enlarged along with a decrease in the (123) phase formation temperature.Type: GrantFiled: December 18, 1992Date of Patent: November 5, 1996Assignee: Nippon Steel CorporationInventor: Mitsuru Morita
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Patent number: 5563117Abstract: In the production of a 124-type or 123-type superconductor by a sol-gel method using alkoxides of respective metals, the use of a compound wherein a secbutoxy group and a hydroxy group are coordinated with a copper atom gives a superconductor composed of flat particles having a broad C plane. The dimensional ratio defined by l/d is at least 6.7 in the case of the 124-type or is at least 8.4 in the case of the 123-type. It shows a superconducting property at a liquid nitrogen temperature. This superconductor shows a higher critical current density than one obtained by a sintering method.Type: GrantFiled: December 15, 1994Date of Patent: October 8, 1996Assignees: Kyocera Corporation, International Superconductivity Technology Center, Sanyo Electric Co., Ltd.Inventors: Shinichi Koriyama, Takaaki Ikemachi, Hisao Yamauchi
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Patent number: 5556831Abstract: A method of treating a part made of a superconductive ceramic of the (Ln).sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-.delta. type, where Ln is chosen from the rare earth elements other than cerium and terbium, the method being designed to reduce the value of .delta., in which method said part is heat treated in an oxidizing atmosphere, said method being wherein, during said treatment, an electric current with a density lying in the range 0.1 A/cm.sup.2 to 2 A/cm.sup.2 is caused to flow through said part, said treatment atmosphere having a partial pressure of oxygen lying in the range 0.1 atmospheres to 1 atmosphere, the treatment temperature lying in the range 200.degree. C. to 500.degree. C., and the duration of said treatment lying in the range 1 hour to 200 hours.Type: GrantFiled: June 21, 1994Date of Patent: September 17, 1996Assignee: Alactel Alsthom Compagnie Generale d'ElectriciteInventors: Alain Wicker, Jean-Pierre Bonnet, Mariano Sanz, Patrice Dordor, Christophe Magro
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Patent number: 5556830Abstract: Improved superconducting oxides are provided having the general formula (Hg.sub.1-x Tl.sub.x)Ba.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+2+.alpha. where x is from about 0.05-0.5 and n is 1, 2, 3 or 4, and .alpha. is an oxygen enrichment factor. The Tl-doped oxides exhibit very high T.sub.c and J.sub.c values.Type: GrantFiled: May 31, 1994Date of Patent: September 17, 1996Assignee: Midwest Superconductivity, Inc.Inventors: Guifu Sun, Kai W. Wong, Ying Xin
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Patent number: 5527765Abstract: A high temperature superconductor and composite structure. A superconductor is disposed on a silver substrate without interdiffusion. The superconductor is formed by heating to a temperature not exceeding the peritectic point of the superconductor material, providing an oxidizing atmosphere while not exceeding the melting point of silver and disposing the superconductor on the silver substrate.Type: GrantFiled: August 23, 1994Date of Patent: June 18, 1996Assignee: Illinois Superconductor CorporationInventors: James D. Hodge, Lori J. Klemptner
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Patent number: 5525585Abstract: The present invention provides a process for the preparation of YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor which comprises surrounding a sintered material in which the molar ratio of Y:Ba:Cu is 2:1:1 with liquid-forming powder and subjecting the powder compact to isothermal heat-treatment at a temperature below the peritectic temperature of YBa.sub.2 Cu.sub.3 O.sub.7-x. The YBa.sub.2 Cu.sub.3 O.sub.7-x superconductors prepared according to the present invention have aligned grain structure in one direction and thus exhibit a high critical current density.Type: GrantFiled: June 16, 1994Date of Patent: June 11, 1996Assignee: Korea Advanced Institute of Science and TechnologyInventors: Jeong-Hun Suh, Young A. Jee, Suk-Joong L. Kang, Duk Y. Yoon
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Patent number: 5523284Abstract: In accordance this invention, there is provided a process for making a bulk superconductive material. In the first step of this process, a diffusion couple is formed from superconductor oxide and impurity oxide. Thereafter, the diffusion couple is heated to a temperature in excess of 800 degrees Centigrade, cooled at a controlled rate, and annealed.Type: GrantFiled: September 30, 1994Date of Patent: June 4, 1996Assignee: Alfred UniversityInventors: James G. Fagan, Jr., Vasantha R. W. Amarakoon
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Patent number: 5512538Abstract: Provided is a metal oxide material represented by the composition formula of Ln.sub.a Sr.sub.b Cu.sub.3-x M.sub.x O.sub.c, where 2.7.ltoreq.a+b.ltoreq.3.3; 0.8.ltoreq.a.ltoreq.1.2; 6.ltoreq.c.ltoreq.9; and 0.05 .ltoreq.x.ltoreq.0.7, Ln is at least one element selected from the group of elements of Y and lanthanoids or an atomic group consisting of said elements, and M is at least one element selected from the group of elements of Ti, V, Ga, Ge, Mo, W and Re or an atomic group consisting of said elements.Type: GrantFiled: June 27, 1994Date of Patent: April 30, 1996Assignee: Canon Kabushiki KaishaInventors: Tohru Den, Tamaki Kobayashi
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Patent number: 5512542Abstract: A novel metallic oxide of a Ln-Ca-Sr-Ba-Cu-B-O type and a process for manufacturing such a metallic oxide. The above metallic oxide has a composition expressed by the following formula (I):(Ln.sub.1-a Ca.sub.a)(Sr.sub.2-b Ba.sub.b)(Cu.sub.3-c B.sub.c)O.sub.d(I)wherein Ln is one or more kinds of elements selected from the group consisting of Y and lanthanoid elements except for Ce and Tb and wherein the following conditions are met: 0.1.ltoreq.a.ltoreq.0.5, 0.7.ltoreq.b.ltoreq.1.7, 0.1.ltoreq.c.ltoreq.0.5, and 6.5.ltoreq.d.ltoreq.7.5. A process for manufacturing the metallic oxide has the following steps. A mixture of materials including H.sub.3 BO.sub.3 used as a starting material of B is prepared. The resultant mixture is heated at a rate of 5.degree. C. or lower per minute up to 900.degree. C. or lower. Then, it is heated in an oxygen atmosphere at a range from 900.degree.-1050.degree. C.Type: GrantFiled: August 30, 1994Date of Patent: April 30, 1996Assignee: Canon Kabushiki KaishaInventors: Tohru Den, Norio Kaneko, Tamaki Kobayashi
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Patent number: 5508253Abstract: The present invention is characterized in that oxides of Y, Ba and Cu having a superconductive substance-forming composition are melted, the melt is rapidly cooled and solidified, the obtained sheet is heated at a temperature of 1000.degree. to 1350.degree. C. to produce a partially melted state thereof, and the sheet is gradually cooled at a rate lower than 200.degree. C./hr, whereby a micro-structure in which precipitates of the RE.sub.2 BaCuO.sub.5 phase having a diameter smaller than 20 .mu.m are dispersed in the REBa.sub.2 Cu.sub.3 O.sub.7-y crystal is obtained.Type: GrantFiled: April 17, 1995Date of Patent: April 16, 1996Assignee: Nippon Steel CorporationInventors: Mitsuru Morita, Katsuyoshi Miyamoto, Masato Murakami, Shoichi Matsuda
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Patent number: 5504226Abstract: In the production of a 124-type or 123-type superconductor by a sol-gel method using alkoxides of respective metals, the use of a compound wherein a sec-butoxy group and a hydroxy group are coordinated with a copper atom gives a superconductor composed of flat particles having a broad C plane. The dimensional ratio defined by l/d is at least 6.7 in the case of the 124-type or is at least 8.4 in the case of the 123-type. It shows a superconducting property at a liquid nitrogen temperature. This superconductor shows a higher critical current density than one obtained by a sintering method.Type: GrantFiled: November 23, 1994Date of Patent: April 2, 1996Assignees: Kyocera Corporation, International Superconductivity Technology Center, Sanyo Electric Co., Ltd.Inventors: Shinichi Koriyama, Takaaki Ikemachi, Hisao Yamauchi
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Patent number: 5502029Abstract: Superconductors using oxide superconducting materials having pinning centers inside crystal grains are enhanced in transmissible critical current density and allowed to have a high critical current density even in the magnetic field. A superconductor is produced comprising superconducting materials having a high irreversible magnetic field where the c axes of their crystals are oriented in one direction. This can be practically realized by heat-treating a superconducting material having the composition (Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2)(Sr.sub.1-X3 Ba.sub.X3).sub.2 Ca.sub.2 Cu.sub.3 O.sub.9+X4 together with Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8 having a tendency of growing in the form of plate crystal. Various apparatuses capable of working under cooling with liquid nitrogen let alone with liquid helium and having a high superconducting critical current density even in a high magnetic field can be produced.Type: GrantFiled: January 26, 1994Date of Patent: March 26, 1996Assignee: Hitachi, Ltd.Inventors: Toshiya Doi, Atsuko Soeta, Seizi Takeuchi, Tomoichi Kamo, Shinpei Matsuda
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Patent number: 5498594Abstract: A high temperature superconducting system comprising M--R--Tl--Sr--Cu--O wherein: M is at least one compound selected from the group consisting of Hg, Pb, K, and Al; and R represents rare earth metals. In one embodiment, a composition forms a 93K superconducting phase having the composition: M--R--Tl--Sr--Cu--O wherein: M is selected from the group consisting of Hg and Al; and R is a rare earth metal. In another embodiment, the composition comprises M--R--Tl--Sr--Cu--O wherein: M is selected from the group of Pb and/or K; and R is a rare earth metal.Type: GrantFiled: February 17, 1994Date of Patent: March 12, 1996Assignee: University of ArkansasInventors: Zhengzhi Sheng, John Meason, Ying Xin
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Mercury-thallium-barium-calcium-strontium-copper-oxide 1223 superconductor and method of making same
Patent number: 5492885Abstract: Mercury-thallium based superconductors with the formula Hg.sub.1-x Tl.sub.x Ba.sub.2 (Ca.sub.1-y Sr.sub.y).sub.2 Cu.sub.3 O.sub.8+.delta. ; change "their preparing method, in particular characterized in that it" to and a method for preparing them. The new superconductors are prepared by reacting respective ternary oxides, such as Ba.sub.2 CuO.sub.3+x and Ca.sub.1-y Sr.sub.y CuO.sub.2, to reduce the formation of an impure phase and by substituting thallium (Ti) a portion of the mercury (Hg) conventionally used in mercury-based superconductors of similar structure, in order to thermally stabilize the superconductor and provide it with a high critical current density characteristic.Type: GrantFiled: August 17, 1994Date of Patent: February 20, 1996Assignee: Korea Research Institute of Standards and ScienceInventors: Yong H. Hur, Yong K. Park, Jong C. Park -
Patent number: 5492886Abstract: Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed.Type: GrantFiled: April 15, 1994Date of Patent: February 20, 1996Assignee: Regents of the University of CaliforniaInventor: Donald E. Morris
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Patent number: 5462917Abstract: A superconductor material having a current density, J, of from about 30,000 to about 85,000 amps/cm.sup.2 at zero magnetic field and 77.degree. K is disclosed. The 123 superconductor, of the formula L.sub.1 Ba.sub.2 Cu.sub.3 O.sub.6 +.delta. wherein L is preferably yttrium, is capable of entrapping sufficiently high magnetic fields and exhibits a low microwave surface resistance. The process of preparing the superconductor comprises compacting the bulk product, L.sub.1 Ba.sub.2 Cu.sub.3 O, and then sintering the reaction product at a temperature between about 40.degree. C. to about 90.degree. C. below its melting point, i.e., for Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.6 +.delta. at a temperature of approximately 940.degree. C. The composition is then heated in a preheated chamber maintained at approximately 1090.degree. C. to about 1,200.degree. C. (approximately 1,100.degree. C. for Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.6 +.delta.Type: GrantFiled: February 14, 1994Date of Patent: October 31, 1995Assignee: University of Houston-University ParkInventors: Kamel Salama, Venkatakrishnan Selvamanickam
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Patent number: 5434125Abstract: A rare earth oxide superconducting material represented by REBa.sub.2 2Cu.sub.3 O.sub.y (RE is Y, Gd, Dy, Ito, Er or Yb), comprises oxide grains and at least one element selected from Rh and Pt, uniformly dispersed in the grain in a proportion of 0.01-5% by weight (in terms of element) based on the rare earth oxide superconducting material. The rare earth oxide superconducting material can be produced by a melt processing and gives a high critical current density even in a highly magnetic field.Type: GrantFiled: June 8, 1994Date of Patent: July 18, 1995Assignees: International Superconductivity Technology Center, NGK Insulators, Ltd., Toyota Jidosha Kabushiki KaishaInventors: Naoyuki Ogawa, Takenobu Sakai, Izumi Hirabayashi
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Patent number: 5432143Abstract: A method of producing a microcrystalline RBa.sub.2 Cu.sub.3 O.sub.y structure where R denotes a lanthanide chosen from Y, La, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb and Lu and where y has a value between 6.9 and 7 starts with a powder of composition [x(123) ; (1-x) (7BaO--18CuO] where (123) denotes the 123 phase of RBaB.sub.2 Cu.sub.3 O.sub.y and where the value of x is between 0.01 and 1. The powder is compressed and sintered at a temperature below 920.degree. C. (the BaCuO.sub.2 and CuO binary eutectic temperature) to form a sample. The sample is placed on an oxide of the lanthanide R. The sample and its support undergo heat treatment enabling chemical reaction between the liquid part of the sample and its support whereby substantially all of the liquid part is consumed and highly regular 123 monocrystals are obtained. Cooling is applied. At least one annealing is carried out in pure oxygen at a temperature between 350.degree. C. and 500.degree. C. to obtain the orthorhombic form characteristic of RBa.sub.2 Cu.Type: GrantFiled: January 11, 1994Date of Patent: July 11, 1995Assignee: Alcatel Alsthom Compagnie Generale D'ElectriciteInventors: Nadia Pellerin, Philippe Odier
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Patent number: 5409887Abstract: A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.Type: GrantFiled: February 25, 1993Date of Patent: April 25, 1995Assignee: The University of ChicagoInventor: Uthamalingam Balachandran
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Patent number: 5395820Abstract: An oxide superconductor comprising a crystal of LnBa.sub.2 Cu.sub.3 O.sub.y (wherein Ln is at least one of rare earth elements including Y) and, finely dispersed therein, Ln.sub.2 BaCuO.sub.5 and a composite oxide of PtBaCuO having an average particle diameter of 0.1 to 10 .mu.m is disclosed. The oxide superconductor is produced by melting a raw material powder comprising a composite oxide of Ln, Ba and Cu, rapidly solidifying the melt, pulverizing the resultant solid, mixing a Pt powder with the pulverized mixture, forming a resultant mixture, heating a resultant formed body to bring the formed body to a partially-molten state and cooling the partially-molten material.Type: GrantFiled: December 1, 1992Date of Patent: March 7, 1995Assignees: International Superconductivity Technology Center, Hokuriku Electric Power Company, Sumitomo Electric Industries, Ltd., Kawasaki Jukogyo Kabushiki Kaisha, Nippon Steel CorporationInventors: Masato Murakami, Tsutomu Takata, Koji Yamaguchi, Akihiro Kondoh, Naoki Koshizuka
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Patent number: 5356868Abstract: A single phase superconducting oxide ceramic material in the form of highly oriented platelets, and a process for the production thereof. The process involves calcining in a non-reducing atmosphere a homogeneous mixture of stoichiometric proportions of suitable precursor materials. The calcination temperature is below the peritectic melt temperature of the superconducting material, and is at or above a temperature and for a time sufficient to effect partial melting of at least one of the precursor materials to a degree sufficient to effect diffusion of at least one of the precursor materials throughout the mixture. The calcination vessel is not wetted by melts of the precursor materials at the calcination temperature. The calcined material is then annealed in a non-reducing atmosphere. A typical material produced by the process is YBa.sub.2 Cu.sub.3 O.sub.x superconducting material, at a calcination temperature of about 976.degree.-982.degree. C.Type: GrantFiled: July 3, 1989Date of Patent: October 18, 1994Assignee: GTE Laboratories IncorporatedInventors: Naomi Naito, Lorraine A. Jachim
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Patent number: 5340794Abstract: The invention comprises a process of heat treatment to produce a high T.sub.c superconductor with increased flux pinning. A precursor compound is subjected to temperature and oxygen pressure conditions at which the precursor compound decomposes or converts partially or completely to the high T.sub.c superconductor and precipitated non-superconducting compounds which are dispersed through the structure of the high T.sub.c superconductor and which are effective to pin lines of magnetic flux. The precursor compound may or may not itself be a high T.sub.c superconductor. In the YBCO system, 2-4-7 may be converted to 1-2-3 or 1-2-3 to 2-4-7 and flux pinning copper oxides dispersed through the structure, for example, various other transformations are possible.Type: GrantFiled: March 18, 1992Date of Patent: August 23, 1994Assignee: Her Majesty the Queen in right of New ZealandInventors: Jeffery L. Tallon, Donald M. Pooke
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Patent number: 5308799Abstract: The present invention relates to an oxide superconductor comprising a composite oxide of RE , Ba and Cu, wherein the superconductor comprises a micro structure comprised of a monocrystalline REBa.sub.2 Cu.sub.3 O.sub.7-x phase (123 phase) and a RE.sub.2 BaCuO.sub.5 phase (211 phase) finely dispersed therein, the 123 phase being formed in a plurality of domains respectively for individual RE compositions and in the order of the 123 phase forming temperatures in respective layers.Type: GrantFiled: February 6, 1992Date of Patent: May 3, 1994Assignee: Nippon Steel CorporationInventors: Mitsuru Morita, Keiichi Kimura, Katsuyoshi Miyamoto, Kiyoshi Sawano, Seiki Takebayashi, Masamoto Tanaka
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Patent number: 5306697Abstract: A superconductor material having a current density, J, of from about 30,000 to about 85,000 amps/cm.sup.2 at zero magnetic field and 77.degree. K. is disclosed. The 123 superconductor, of the formula L.sub.1 Ba.sub.2 Cu.sub.3 O.sub.6 +.delta. wherein L is preferably yttrium, is capable of entrapping sufficiently high magnetic fields and exhibits a low microwave surface resistance. The process of preparing the superconductor comprises compacting the bulk product, L.sub.1 Ba.sub.2 Cu.sub.3 O, and then sintering the reaction product at a temperature between about 40.degree. C. to about 90.degree. C. below its melting point, i.e., for Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.6 +.delta. at a temperature of approximately 940.degree. C. The composition is then heated in a preheated chamber maintained at approximately 1090.degree. C. to about 1,200.degree. C. (approximately 1,100.degree. C. for Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.6 +.delta.Type: GrantFiled: August 23, 1991Date of Patent: April 26, 1994Assignee: University of Houston - University ParkInventors: Kamel Salama, Venkatakrishnan Selvamanickam
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Patent number: 5244871Abstract: An oxide superconductor comprises a composition represented by the composition formula: (Nd.sub.x --Ce.sub.y --L.sub.z).sub.2 CuO.sub.4-d (wherein L is an element selected from Ca and Mg, and x+y+z=1). The compositions of Nd, Ce and L of the oxide superconductor corresponds to a point falling inside an area of Nd--Ce--L ternary diagram surrounded by straight lines (A-B), (B-C), (C-D) and (D-A) connecting point (A) with point (B), point (B) with point (C), point (C) with point (D) and point (D) with point (A), respectively, the points (A), (B), (C) and (D) being points (x=1, y=0, z=0), (x=0.4, y=0.6, z=0), (x=0.4, y=0.3, z=0.3) and (x=0.1, y=0, z=0.9), respectively, in the Nd--Ce--L ternary diagram. Above-described Nd--Ce--L--Cu--O oxides can exhibit superconductivity within a wide range of composition when heat-treated in an atmosphere of nitrogen.Type: GrantFiled: October 9, 1991Date of Patent: September 14, 1993Assignees: Mitsubishi Metal Corporation, Hitachi, Ltd., International Superconductivity Technology CenterInventors: Takeshi Sakurai, Toru Yamashita, Hisao Yamauchi, Shoji Tanaka