WO1988008618A2 - Dispositifs supraconducteurs en ceramique et procedes de fabrication - Google Patents

Dispositifs supraconducteurs en ceramique et procedes de fabrication Download PDF

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Publication number
WO1988008618A2
WO1988008618A2 PCT/GB1988/000330 GB8800330W WO8808618A2 WO 1988008618 A2 WO1988008618 A2 WO 1988008618A2 GB 8800330 W GB8800330 W GB 8800330W WO 8808618 A2 WO8808618 A2 WO 8808618A2
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WO
WIPO (PCT)
Prior art keywords
composite
superconducting
tube
fabrication
oxygen
Prior art date
Application number
PCT/GB1988/000330
Other languages
English (en)
Other versions
WO1988008618A3 (fr
Inventor
Jan Edgar Evetts
Bartlomiej Andrzej Glowacki
Original Assignee
Evetts Jan E
Bartlomiej Andrzej Glowacki
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Evetts Jan E, Bartlomiej Andrzej Glowacki filed Critical Evetts Jan E
Publication of WO1988008618A2 publication Critical patent/WO1988008618A2/fr
Publication of WO1988008618A3 publication Critical patent/WO1988008618A3/fr
Priority to KR1019880701791A priority Critical patent/KR890700929A/ko
Priority to DK533289A priority patent/DK533289D0/da
Priority to FI895119A priority patent/FI895119A0/fi

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H10N60/0268—Manufacture or treatment of devices comprising copper oxide
    • H10N60/0801—Manufacture or treatment of filaments or composite wires

Definitions

  • This invention concerns superconducting materials and their manufacture and is directed to improvements in the design and fabrication of high critical temperature superconducting composite conductors.
  • high critical temperature superconducting composite conductors typically such conductors depend for their superconducting properties on high field, high critical temperature superconducting oxide or nitride phases, and possess superconducting properties above 77°K.
  • these materials are chemically extremely active, in particular exhibiting extreme sensitivity to the presence of oxygen and moisture, and in view of their extreme chemical activity, the components are also susceptible to corrosion and environmental degradation.
  • the design of a composite conductor for operation at 77°K and above presents fewer problems than at lower temperatures.
  • the specific heat of materials is an order of magnitude, or more, greater, at elevated temperatures and this makes the design of a thermally stable conductor simpler.
  • the invention seeks to provide a method of construction and manufacture which enables brittle reactive superconducting oxide or nitride phases to be incorporated into a robust, prestressed, environmentally protected high critical current composite conductor, and to provide a form of construction in which the conductor may be reactivated into an optimum state should its performance deteriorate with time.
  • a method of forming a superconducting composite from an outer supporting casing of a non-superconducting inert material having active high temperature superconducting material in the form of a thick walled tube located therewithin which involves the step of passing oxygen through the hollow interior of the tube to produce oxidation of the active material, to create a superconducting oxide phase after fabrication.
  • Fabrication may involve for example laying up, or winding into a coil, incorporation into a machine or device.
  • the composite may be cooled or heated to obtain the devised oxidation.
  • the internal oxidation process may be carried out in more than one step, with oxygen being reintroduced into the hollow interior at intervals after previously introduced oxygen has been partially consumed in the reaction process.
  • the oxygen may be introduced under high pressure.
  • oxidation is controlled so as to produce a superconducting phase having the properties for the particular application in mind.
  • the hollow interior is defined by a tube of oxygen permeable metal such as a silver or alloy.
  • This inner tube gives support to the superconducting material during fabrication and reaction but is penetrable by oxygen to enable the oxidation step to be performed.
  • the final composite conductor will normally be required to be of relatively small cross-section and relatively much greater length.
  • the composite may be formed by extrusion over a mandrel so as to provide the hollow interior and if initial extrusion does not provide the desired final cposs-sectional size, the latter may be achieved by drawing in known manner.
  • the region of the cross-section which is to comprise the hollow core may be filled with a suitable material which can be removed readily after fabrication. This material may be left in place during any subsequent drawing to further reduce the cross-sectional area of the composite.
  • -it must be capable of being removed so as to enable oxygen to be pumped along the hollow interior to produce the oxidation of the material coating the inside of the supporting casing to form the superconducting material previously referred to.
  • This process may for example involve the use of a ductile metal or metal alloy, wax or the use of water or other liquid such as castor oil which may be frozen into the cross-section region of the composite prior to the fabrication stages — _> - and then removed by heating or other convenient means typically under pressure so as to enable the cross-section of the final fabrication to be heated and then oxidised in the manner required by the invention.
  • the invention is not limited to a composite with only a single superconducting element within the cross-sectional area of the composite, but envisages composites having two or more such superconducting elements within the cross-section of the composite, extending the length of the composite.
  • the starting materials from which the superconducting layer is to be formed may for example consist of mixed powdered oxides, carbonates, or other compounds such as co-precipitated nitrates or metals in any combination, and typically the starting materials are pre-treated, reacted, graded and preferably magnetically separated prior to insertion into the composite.
  • the starting materials referred to are in the form of a clinker when in the solid and the first' step will typically involve grinding the clinker or other solid form into a powder. If this is then cooled to a temperature at which the material becomes superconducting (typically the temperature of liquid nitrogen) a magnetic field will cause any superconductive powder to move due to the interaction between the magnetic field and the induced currents in the conductive material and this can be used to separate superconductive powder particles from non- superconducting particles.
  • the superconductive particles can be caused to levitate or simply be deflected depending on the direction of the magnetic field and the design "of the separator.
  • the non- separated material may typically be reprocessed and subjected to a further magnetic separation, to further refine the material.
  • Carbonates may be used as the raw material if an oxide is not available or is not suitable. Mention has also been made of the use of co— recipitated nitrates as possible starting materials and examples are typically co- precipitates from aqueous solution of yttrium nitrate, barium nitrate and copper nitrate.
  • the composite will normally have to be cooled before it is subjected to extrusion or swaging or wire drawing techniques since all of which normally increase the temperature of the composite and could cause a failure of the cavity forming characteristic of the substitute material within the core of the composite.
  • the outer supporting casing is formed from copper or stainless steel and the wall of the hollow core is formed from silver or silver alloy with the high temperature superconductor material sandwiched therebetween.
  • the inner surface of the outer supporting casing is nickel or silver or tantalum lined.
  • a composite typically has an initial diameter of 75mm with an outer support casing thickness-of 12.5mm, a powder annulus having a radial thickness of some 15mm, an inner copper liner of 1mm thickness and a central core of substitute material of diameter 18mm.
  • the fina diameter of the conductor would be of the order of 1 to 2mm.
  • Preferred materials for the substitute core material are low melting point lead alloys, wax, and inorganic salts.
  • the removal of the material and the oxidation of the superconductive material may be achieved simultaneously by using oxygen under pressure to remove the unwanted substitute material.
  • the composite preferably includes an outer electrical insulating layer.
  • non-reactive strengthening rods, fibres or mesh material may be located within the powder sleeve of the initial composite and worked as by extrusion or otherwise with the remaining materials of the composite so as to extend along the length of the final composite within the superconducting region. Since this region is conductive, it is probably irrelevant whether the strengthening material is itself conductive or non- conductive. However where it is conductive, this will. - 8 - further assist in stabilising the superconductive material which, as is well known, can be damaged if .local hot-spots occur.
  • the nickel, silver or tantalum coating of the interior of the support casing reduces the reaction which may otherwise occur between the outer casing and the alkali metals or important rare earth materials which will be present in the superconducting layer.
  • gold may be used in place of nickel, silver or tantalum.
  • the invention thus provides a support sheath for very brittle and readily damaged superconducting materials which not only protects the latter against degradation and attack from elements such as water, but also provides mechanical structural support.
  • the outer support sheath if not also any inner support sheath, must be capable of conducting electricity to stabilise the" superconductor and where reinforcing elements are employed throughout the cross-section of the superconducting material, these are also, advantageously, electrically conductive.
  • the invention also enables an insulating outer surface to be provided which will enable separation between windings in a coil and the like.
  • the invention also lies in a method of fabricating a superconducting composite involving the steps of forming as an annular sandwich between two conductive tubular - 9 - members, a layer of a material which on subsequent processing can be rendered superconductive; extruding, swaging, drawing or otherwise forming the composite into a conductor of desired overall cross-section whilst ensuring that the internal tube does not collapse so that a hollow passage extends throughout the entire length of the finally fabricated conductor; forming the latter into a coil or other electrical component by shaping, forming or otherwise; passing a reactive gas or vapour or liquid through the hollow interior of the formed composite whilst maintaining the temperature of the formed composite at a temperature at which appropriate reaction will occur to form the sandwiched material into a superconductive material.
  • the internal tubular member may be filled with a removable substance such as a metal having a melting point lower than that of the other materials which the composite is formed, a metal alloy, castor oil, wax or even water so as to prevent the collapse of the inner tubular member during the working of the initial composite to achieve the cross- section size reduction and this substitute material is advantageously removed before the final reaction phase at which the gas or vapour or other material which is to be reacted with the sandwiched material is passed through the central core, whilst maintaining the composite at the appropriate temperature so as to achieve the desired reaction and render the elongated annulus of material superconductive.
  • a removable substance such as a metal having a melting point lower than that of the other materials which the composite is formed, a metal alloy, castor oil, wax or even water
  • the material is either removable before the reaction stage or is permeable to the gas vapour or liquid which is to react with the sandwiched material.
  • a layer of nickel or tantalum is applied to the inner surface of the outer conductive sheath before the space between it and the inner core is filled with a material which after reaction is to be the superconducting medium.
  • a layer of gold or silver may advantageously be applied to the inner surface of the nickel or tantalum layer before the material which is to be reacted to from the superconductive material is added.
  • the inner support tube is of metal such as silver or copper since other materials may be used such as a plastic materials., the only requirement being that the material concerned is permeable to the reactive agent which is to be added to the composite at the time when the material sandwiched between the inner and outer supports is to be rendered superconducti e.
  • Figure 1 is a cross-section of a composite conductor constructed in accordance with the present invention
  • Figure 2 is a cross-section through a silver yttrium barium copper oxide reference wire having an outer diameter of 1.5mm
  • Figure 3 is a cross-section through a multicore hollow core conductor
  • Figure 4 is a cross-section through a single hollow core conductor
  • Figure 5 illustrates the critical current transition for the reference wire at (a) and for silicone at (b) , the reference wire with a silica addition
  • Figure 6. is an axial section through a circular section hollow conductor constructed in accordance with the invention/
  • Figure 7 is a cross-section on the line AA through the . hollow single core conductor of Figure 6,
  • Figure 8 is a cross-section through a twin conductive tape having a twin core and stainless steel outer
  • Figure 9 illustrates graphically the resistive transition at 77K in zero magnetic field for external diffusion (ED) conductors sintered for 24 hours at 940°C under oxygen, having an outer diameter of yttrium barium copper oxide of 0.7mm,
  • Figure 10 illustrates graphically the critical current value as a function of heat treatment time for ED conductor under oxygen at 940 ⁇ C (starting material: powder after calcination (SSR)) with the outer diameter of the yttrium barium copper oxide of 0.7mm,
  • Figure 11 illustrates graphically the reduced critical current i as a function of preform particle size.
  • the applied field Ha perpendicular to the current direction.
  • Figure 12 illustrates graphically resistive transitions at (a) internal diffusion twin filament composite and at (b) external diffusion (ED) single filaments.
  • Figure 13 illustrates graphically the reduced critical current i as .function of load P for an ED wire under
  • the composite is shown as comprising an outer stainless steel sheath 10 and an inner silver sheath 12 between which is sandwiched an annulus of high " temperature superconducting material 14. Between " the latter and the outer sheath 10 is a thin film of nickel 16 and within the annulus are located elongated fibres 18 which reinforce the structure. Although shown in the drawing, it is to be understood that these reinforcing fibres are optional.
  • the hollow inte ior of the tube 12 is initially filled with a removable material, such as a low melting point alloy and this serves to " ensure that the inner tube 12 does not collapse during the reducing steps.
  • the core of material within the tube 12 is removed before the final stage of processing which involves passing a gas vapour or liquid through the tube which can permeate through the wall of the tube into the material 14 and react therewith to render the latter superconducting.
  • oxygen is passed through the hollow tube 12 after the core material has been removed and the composit is maintained at an appropriate temperature at which oxidation of the material 14 will occur as the oxygen 5 permeates through the wall of the tube 12.
  • the method of the invention also involves the formation o the composite into a component such as a coil or the like before the core material is removed from the tube 12.
  • the invention also lies. in superconducting composite 10 conductors when formed by the method of the invention.
  • composition, state of order, microstructure and defect structure of the superconductor must be optimised to support a high critical current density.
  • a single hollow core 15' is surrounded by a silver layer 25 separating 4 from the superconducting material 27 which is itself surrounded by a metal foil 29 separating it from a stainless steel outer 31.
  • the critical current of the multicore conductor was about 60 A cm -2 at 77K. At present this is limited by difficulty in making contact to the wire and by contamination of the internal surface of the rather irregular hollow core.
  • the internal diffusion method of invention enable ' s a good oxygen supply to the superconductor metal especially in t e single hollow core arrangement of Figure 4.
  • the critical current had a minimum value for a perpendicular applied field which points to the importance of powder compaction in the design of commercial conductors.
  • a copper end stop (22) was screwed into one end of the tube to retain the inner portions of the composite during assembly and fabrication of the composite.
  • the tube was then lined with nickel foil (24) fitted closely to its inner surface.
  • a silver tube filled with low melting points Wood's metal was placed centrally in the stainless steel tube supported on the copper end stop.
  • the silver tube was prepared by filling a silver tube (26) of wall thickness 0.5mm and internal diameter 5mm with Wood's metal (28) and cold swaging to a final external diameter of 2.5mm prior to the insertion into the stainless steel tube (20) .
  • the resulting annular space was filled up completely with superconducting YBa.-.Cu-.O.-, powder (30) using a stainless steel rammer.
  • the assembled composite was cold swaged to a wire having 3mm outside diameter *
  • the copper containing end sections were cut-off and a plastics tube was sealed over one end and connected to a source of compressed air.
  • the composite wire was then immersed in boiling water and the molten Wood's metal extruded under the . action of the compressed air.
  • the inside of the silver tube was then cleaned using flowing acid, and the completed composite wire was finally sintered in a furnace at 920°C with a flow of oxygen passing through the hollow core to optimise the oxidation of the superconductor by diffusion of oxygen through the inner silver layer, after which the sample was slowly cooled in flowing oxygen.
  • a stainless steel tube (40) was prepared by being cold rolled until it had two parallel sides and contained a flattened interior hole.
  • Three silver clad wires of identical diameter surrounded by nickel foil (39) were inserted lengthwise into the tube (40).
  • the " two outer wires contained yytrium barium copper oxide superconducting powder prepared by filling -a silver tube having a 0.5mm wall thickness and a _5mm internal diameter with powder, one end sealed with a copper end stop, and swaging the tube down to 2mm diameter.
  • the third central wire contained Wood's metal. *
  • the whole composite was further rolled until the wires occupied the whole of the internal space in the tube.
  • the ends of the wire were then cut-off and the exposed ceramic ends were covered by silicone rubber.
  • a tube was connected to one end of the composite and the other end of the tube was connected to a source of compressed air.
  • the composite was immersed in boiling water and the Wood's alloy was removed by the air pressure.
  • the internal surface of the tube was cleaned by acid flow after which the now hollow composite was placed in an oven for sintering. During sintering oxygen was blown through the central hollow core iri the wire.
  • the preform powders investigated were prepared from BaC0_, Y_0 3 and CuO powders (Johnson Matthey, - 99.999% purity) using two methods. Firstly powders mixed in stoichiometric proportion were prepared by solid state reaction solid state reaction (SSR) powders were investigated both after the initial calcination stage and when fully superconducting. Secondly the starting powders were dissolved in nitric acid and superconducting powders prepared by a citrate synthesis route (CS).
  • SSR solid state reaction solid state reaction
  • ID Internal diffusion (ID) composites - Steel clad hollow core composites were constructed in a variety of • geometries. Single core, twin core and multicore ' " composites have been tested. In each case the hollow core region was built using a metal core which was removed ,after fabrication to the final diameter, by chemical means or by melting. Both external and internal composites were reaction sintered after fabrication at about 940*C under oxygen and slowly cooled.
  • Ic obser_ve_d in YBa- 2.Cu- 3O-,-x in both I and ED conductors is 900Acm in zero field at 77K.
  • I is still very low compared to commercial superconductors the results demonstrate clearly the feasibility of fabricating internal diffusion conductors with steel cladding.
  • the ID designs are mechanically robust because of the rigidity of the cladding and becaus the brittle ceramic is under compression. Such ID conductors withstand high loads without degradation of I .

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

L'étape finale d'un procédé de fabrication d'un composite supraconducteur comprenant un logement de support externe (10, 31) d'un matériau inerte non supraconducteur contenant un matériau actif supraconducteur à haute température (14, 27) tel que du YBa2Cu3O7, sous la forme d'un tube à paroi épaisse placé dans ledit logement, fait appel au passage d'oxygène dans l'intérieur creux (15') du tube, afin de provoquer l'oxydation du matériau actif et créer ainsi une phase d'oxyde supraconductrice. Le procédé d'oxydation interne peut être effectué en plus d'une étape. Les modifications dimensionnelles qui se produisent durant ce processus peuvent soumettre la phase supraconductrice à de forces de compression. Une garniture d'un métal (12, 25) perméable à l'oxygène, tel que l'argent, l'or ou un alliage, sert de support au matériau supraconducteur durant la fabrication. Une couche faisant office de barrière (16, 29) d'un métal tel que nickel ou le tantale recouvre de préférence la surface intérieure du logement de support externe (10, 31). Le noyau évidé peut être rempli d'un matériau amovible lors de la fabrication, et peut être débarassé après la fabrication. Le supraconducteur peut être réalisé dans une bobine d'autres dispositifs. En outre le composite supraconducteur décrit comprend en tant que partie intégrante, une enveloppe de support pour un manchon interne en matériau à base d'oxyde supraconducteur fragile et facilement endommageable (YBa2Cu3O7), afin de protéger la manchon contre les dégradations et les agressions par des éléments tels que l'eau, et aussi afin de former un support de structure mécanique. L'enveloppe de support est également électroconductrice de façon à stabiliser la supraconducteur.
PCT/GB1988/000330 1987-04-29 1988-04-28 Dispositifs supraconducteurs en ceramique et procedes de fabrication WO1988008618A2 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
KR1019880701791A KR890700929A (ko) 1987-04-29 1988-12-29 세라믹 초전도소자 및 그 제조방법
DK533289A DK533289D0 (da) 1987-04-29 1989-10-26 Keramiske superledende indretninger og fremgangsmaade ved fremstilling heraf
FI895119A FI895119A0 (fi) 1987-04-29 1989-10-27 Keramiska supraledande anordningar och framstaellningsmetoder.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8710113 1987-04-29
GB878710113A GB8710113D0 (en) 1987-04-29 1987-04-29 Superconducting composite

Publications (2)

Publication Number Publication Date
WO1988008618A2 true WO1988008618A2 (fr) 1988-11-03
WO1988008618A3 WO1988008618A3 (fr) 1988-12-01

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PCT/GB1988/000330 WO1988008618A2 (fr) 1987-04-29 1988-04-28 Dispositifs supraconducteurs en ceramique et procedes de fabrication

Country Status (8)

Country Link
EP (1) EP0357657A1 (fr)
JP (1) JPH02503375A (fr)
KR (1) KR890700929A (fr)
AU (1) AU619468B2 (fr)
DK (1) DK533289D0 (fr)
FI (1) FI895119A0 (fr)
GB (1) GB8710113D0 (fr)
WO (1) WO1988008618A2 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2635223A1 (fr) * 1988-08-02 1990-02-09 Commissariat Energie Atomique Elements composites comportant un coeur en materiau supraconducteur et leur procede de preparation
FR2635222A1 (fr) * 1988-08-02 1990-02-09 Commissariat Energie Atomique Elements composites a base de materiau ceramique supraconducteur et leur procede de preparation
EP0357910A2 (fr) * 1988-08-29 1990-03-14 kabelmetal electro GmbH Matériau allongé supraconducteur d'un tuyau ondulé revêtu
US5044406A (en) * 1987-03-18 1991-09-03 Semiconductor Energy Laboratory Co., Ltd. Pipe made from a superconducting ceramic material
EP0499049A1 (fr) * 1991-02-14 1992-08-19 Vacuumschmelze GmbH Dispositif composite supraconducteur en céramique d'oxyde et procédé pour sa fabrication
GB2256080A (en) * 1991-05-20 1992-11-25 Marconi Gec Ltd Superconductive electrical conductor.
US5474975A (en) * 1987-04-01 1995-12-12 Semiconductor Energy Laboratory Co., Ltd. Method for manufacturing an elongated member from a superconducting ceramic material
GB2399943A (en) * 2002-03-27 2004-09-29 Jefferson Liu Heat dissipating device

Citations (2)

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FR1564936A (fr) * 1968-03-15 1969-04-25
US3623221A (en) * 1966-05-20 1971-11-30 Imp Metal Ind Kynoch Ltd Method of fabricating a tubular superconductor assembly

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CA1338396C (fr) * 1987-02-05 1996-06-18 Kazuo Sawada Procede de fabrication d'un cable supraconducteur, constitue de matiere ceramique de type oxyde
US4952554A (en) * 1987-04-01 1990-08-28 At&T Bell Laboratories Apparatus and systems comprising a clad superconductive oxide body, and method for producing such body
AU596289B2 (en) * 1987-04-14 1990-04-26 Sumitomo Electric Industries, Ltd. Method of the production of ceramic superconductor filaments

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
US3623221A (en) * 1966-05-20 1971-11-30 Imp Metal Ind Kynoch Ltd Method of fabricating a tubular superconductor assembly
FR1564936A (fr) * 1968-03-15 1969-04-25

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Extended Abstracts, High Temperature Superconductors, Proceedings of Symposium S 1987 Spring Meeting of the Materials Research Society, 23-24 April 1987, Anaheim, California, Materials Research Society, (Pittsburgh, US), S. Jin et al.: "Fabrication of 91K superconducting coils", pages 219-221 *
Japanese Journal of Applied Physics, part 2, Letters, volume 26, no. 4, 20 April 1987, (Tokyo, JP), M. Hirabayashi et al.: "Structure and superconductivity in a new type of oxygen deficient perovskites Y1Ba2Cu3O7", pages L454-L455 see page L454 *

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5044406A (en) * 1987-03-18 1991-09-03 Semiconductor Energy Laboratory Co., Ltd. Pipe made from a superconducting ceramic material
US5474975A (en) * 1987-04-01 1995-12-12 Semiconductor Energy Laboratory Co., Ltd. Method for manufacturing an elongated member from a superconducting ceramic material
US5987731A (en) * 1987-04-01 1999-11-23 Semiconductor Energy Laboratory Co., Ltd. Elongated superconductive member
FR2635223A1 (fr) * 1988-08-02 1990-02-09 Commissariat Energie Atomique Elements composites comportant un coeur en materiau supraconducteur et leur procede de preparation
FR2635222A1 (fr) * 1988-08-02 1990-02-09 Commissariat Energie Atomique Elements composites a base de materiau ceramique supraconducteur et leur procede de preparation
EP0357480A1 (fr) * 1988-08-02 1990-03-07 Commissariat A L'energie Atomique Eléments composites comportant un coeur en matériau supraconducteur et leur procédé de préparation
EP0357910A2 (fr) * 1988-08-29 1990-03-14 kabelmetal electro GmbH Matériau allongé supraconducteur d'un tuyau ondulé revêtu
EP0357910B1 (fr) * 1988-08-29 1998-09-16 Alcatel Procédé de fabrication d'un matériau allongé supraconducteur d'un tuyau ondulé revêtu
EP0499049A1 (fr) * 1991-02-14 1992-08-19 Vacuumschmelze GmbH Dispositif composite supraconducteur en céramique d'oxyde et procédé pour sa fabrication
US6028036A (en) * 1991-02-14 2000-02-22 Vacuumschmelze Gmbh Oxide ceramic superconductive composite member and method for manufacture
GB2256080A (en) * 1991-05-20 1992-11-25 Marconi Gec Ltd Superconductive electrical conductor.
GB2399943A (en) * 2002-03-27 2004-09-29 Jefferson Liu Heat dissipating device

Also Published As

Publication number Publication date
GB8710113D0 (en) 1987-06-03
KR890700929A (ko) 1989-04-28
JPH02503375A (ja) 1990-10-11
DK533289A (da) 1989-10-26
DK533289D0 (da) 1989-10-26
FI895119A0 (fi) 1989-10-27
WO1988008618A3 (fr) 1988-12-01
AU619468B2 (en) 1992-01-30
EP0357657A1 (fr) 1990-03-14
AU1708988A (en) 1988-12-02

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