WO1993022799A1 - Materiau composite supraconducteur a revetement d'argent - Google Patents

Materiau composite supraconducteur a revetement d'argent Download PDF

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Publication number
WO1993022799A1
WO1993022799A1 PCT/AU1993/000180 AU9300180W WO9322799A1 WO 1993022799 A1 WO1993022799 A1 WO 1993022799A1 AU 9300180 W AU9300180 W AU 9300180W WO 9322799 A1 WO9322799 A1 WO 9322799A1
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Prior art keywords
phase
composite
superconductor
predominantly
accordance
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PCT/AU1993/000180
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English (en)
Inventor
Shixue Dou
Hua Kun Liu
Yuan Chang Guo
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Unisearch Limited
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Publication of WO1993022799A1 publication Critical patent/WO1993022799A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/45—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides
    • C04B35/4521—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides containing bismuth oxide
    • C04B35/4525—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides containing bismuth oxide also containing lead oxide
    • 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
    • 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

  • the present invention relates to a silver clad or doped superconductor composition and to a process for fabricating the composition. More particularly, the invention relates to the fabrication of silver composites including wires, tapes, multifilaments, silver doped superconductors and any form of the combination of silver and the Bi-Pb-Sr-Ca-Cu-0 superconductor system (BPSCCO system) .
  • BPSCCO system Bi-Pb-Sr-Ca-Cu-0 superconductor system
  • Cu,Cu- Ni/superconductor Nb-Ti multifilament wire has been produced as commercial product, and consists of 14701 filaments with cross-section of each filament 18 urn.
  • T c Transition Temperature
  • metals such as silver and gold
  • silver has been used for making composite superconductors including wires, tapes and multifilaments.
  • This non-poisoning behaviour of Ag is of significant technical importance in the fabrication of Ag-superconductor composites because it offers the attractive features of the possibility of a current shunt, improved environmental resistance, and improved mechanical behaviour, such as flexibility and ductility.
  • These silver composites would have wide commercial and industrial application if the satisfactory values of T c , J c (critical current density) and H c (critical magnetic field) could be attained.
  • These composites could be used for making AC generators, transformers, fault current limiters, power cables, motors, magnetic energy storage, transportation systems and magnetic separation devices.
  • the silver BPSCCO composite superconductor system has a number of advantages, including high T c , over other superconductors, and much work has been done on this superconductor system in the past. Reference should be had to our previously published International Patent Application WO91/00622. Silver-clad tapes and wires have been manufactured which display high T c . However, T c is not the only critical property of superconductors. More important is the property of critical current density (J c ) . The J c for the silver BPSCCO system is adversely affected when the composite is subjected to magnetic fields. As electrical components must often operate in high magnetic fields, and, indeed, magnetic field production is inherent when electrical current flows, most applications of such superconductor composites have been hindered by the low J c and poor behaviour in magnetic fields.
  • the present invention provides a process for the formation of Ag/Bi-Pb-Sr-Ca-Cu-0 superconductor composite, comprising the steps of: heating predominantly high T c 2223 phase 0 Ag/Bi-Pb-Sr-Ca-Cu-0 superconductor composite for a relatively short period of time, at a temperature at which the composite partially melts, whereby to decompose the 2223 phase to predominantly 2212 phase.
  • partially melts does not necessarily mean 5 that the superconductor composite forms a predominantly liquid phase during the "melt". Rather, it indicates a change in the phase of the superconductor structure which results in a decomposition of the high T c 2223 phase for a short period of time and this may include formation of a small amount of liquid phase during the partial melt.
  • partially melts and “partial melt” are used in this sense throughout.
  • relatively short period of time is meant that the time for the partial melt heating step is relatively short compared with the heating steps which are generally used to prepare superconductor composites. These standard heat treatment steps can last anything from 40 to 140 hours.
  • the "relatively short period of time" for which the melt is applied is preferably below 1 hour, and is more preferably 10 to 30 minutes.
  • the temperature of the partial melting step is preferably below 858° to 863°C.
  • the predominantly 2223 phase is preferably recovered by a further processing step at a temperature below the partial melt processing step.
  • the length of the partial melt step and temperatures are chosen so that an optimal amount of 2223 phase is recovered. If the partial melt step is too long (over 1 hour) or at too high a temperature (over 900°C) , it will not be possible to recover an optimum amount of high T c phase.
  • the composition of the superconductor following recovery of the 2223 phase includes an amount of between 2% to 12% and more preferably about 5% to 10% 2212 phase dispersed throughout the composite.
  • the short period melt process also limits the dimension of impurities to a level of submicrons to a few microns when the 2223 phase is recovered.
  • the partial melt step is preferably introduced in the process between annealing cycles.
  • a general example process is as follows:
  • the process of the present invention is preferably used to make silver clad BPSCCO wires or tapes, but may also be used to produce a composite not of tape form or wire form.
  • the present invention further provides a process for the formation of Ag/Bi-Pb-Sr-Ca-Cu-0 superconductor composite, comprising the steps of:
  • the present invention yet further provides a process for the formation of Ag/Bi-Pb-Sr-Ca-Cu-0 superconductor composite, comprising the steps of: initial preparation of a high T c (2223 phase) Ag/Bi-Pb-Sr-Ca-Cu-O ' superconductor composite by appropriate treatment steps; further treating the superconductor composite to decompose the 2223 phase to predominantly 2212 (low T c ) phase; and further treating the composite whereby to recover predominantly 2223 phase composite with a minority of 2212 phase dispersed substantially uniformly through the composite.
  • the step of treating the superconductor composite to decompose 2223 phase involves a heat treatment to a predetermined temperature and for a predetermined time period.
  • the predetermined temperature and predetermined time period are preferably chosen that on application of a subsequent step to recover the 2223 phase an amount of 2212 phase of between 2% to 12% of the composite will remain, distributed uniformly through the predominantly 2223 phase. More preferably, the conditions are chosen so that this amount of 2212 phase is about 5% to 10%.
  • the J c of the superconductor and its performance in a magnetic field are significantly improved, for at least preferred embodiments of the invention, and we believe that the improvements may be attributed to high mass density, intimate connectivity between grains and excellent grain alignment, and highly dispersed 2212 phase and other impurity precipitates serving as effective pinning centres.
  • this (formation-decomposition-recovery)process of the 2223 results in the superconductor having a higher density of dislocations than in previous silver doped BPSCCO composites. This also, we believe, contributes to the improvements in the J C H characteristics.
  • the predetermined temperature is preferably between 858° and 863°C and the predetermined time period is preferably between 10 and 30 minutes.
  • Silver clad wires and tapes may be formed by the process of this aspect of this invention, with any other process steps which are necessary for the formation of the wires and tapes.
  • this aspect of the present invention is not limited to wires and tapes.
  • the present invention further provides a silver/Bi-Pb-Sr-Ca-Cu-0 superconductor composite comprising predominantly 2223 phase (high T c ) composite with a minority proportion of 2212 phase (low T c ) distributed substantially uniformly through the composite.
  • the proportion of 2212 phase is preferably in the range of 2% to 12%.
  • the range is most preferably 5% to 10%.
  • Fig. 1 shows a graph illustrating a process for manufacture of a superconducting wire/tape in accordance with Example 1;
  • Fig. 2 is a graph of J c against magnetic field for superconducting tapes prepared by different processes, in accordance with Example 1;
  • Fig. 3 shows a graph of pinning force against magnetic field for the superconducting tapes of Fig. 2;
  • Fig. 4 shows an x-ray diffractional pattern of the superconducting tape formed by the inventive process, in accordance with Example 1.
  • Fig. 5 shows a graph of J c against magnetic field for a number of silver clad superconductor tapes prepared in accordance with Example 2;
  • Fig. 6 shows the irreversibility lines (IL) for silver-clad superconductor tapes prepared in accordance with the inventive process and a conventional process, in accordance with Example 2;
  • Fig. 7 shows electron micrographs for a silver-clad tape prepared in accordance with the present invention and a conventionally prepared tape, in accordance with Example 2;
  • Fig. 8 shows a series of X-ray diffraction patterns for silver-doped superconductor samples prepared using partial melting steps, in accordance with the present invention, at several different temperatures;
  • Fig. 9 is a graph of phase distribution against temperature for partial melting steps, for the samples of Figure 8, for Example 3;
  • Fig. 10 in relation to Example 3 shows x-ray diffraction patterns illustrating the recovering of the 2223 phase in the superconductor on further processing
  • Fig. 11 shows x-ray diffraction patterns, in relation to Example 3, showing recovery of the 2223 phase for a further sample;
  • Fig. 12, 13 and 14 show that 2223 phase is not recovered on further processing for samples which have been treated using a long period melt;
  • Fig. 15 shows a graph of recovery of 2223 phase against duration of the melting step, in relation to Example 3.
  • Fig. 16 shows scanning electron micrograph images of cross sections of samples before the melting step, after the melting and after post-annealing, in relation to Example 3; and Fig. 17 shows scanning electron micrograph for samples, in relation to Example 3, which have been subjected to a long melt period.
  • Example 1 illustrate the efficacy of the formation-decomposition-recovering process of the present invention, preferably carried out by a short period melt after initial formation of the high T c phase, and its beneficial effect on J c .
  • the powder was calcined at 830°C for 10 hours, pressed into pellets, and sintered at 845°C for 20 hours.
  • X-ray diffraction patterns obtained using a SIEMENS D5000 diffractometer show that the major phases in the samples was (Bi,Pb) 2 Sr 2 CaCu 2 0 8+z (2212); the high-T c phase (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+ (2223) had not been formed at this stage.
  • the powders were then pressed into bars of dimensions 50 mm length and 8 mm diameter.
  • the bars were loaded into a silver tube of 10 mm outer and 8 mm inner diameters, and the composite was then drawn to a final diameter of 0.7 to 1.0 mm.
  • the wires were rolled into tapes of overall thickness approx. 0.15 mm and width approx. 3 mm.
  • the resultant tapes were processed by two different procedures.
  • schedule I the tapes were heat treated at 830°C to 839°C for 70 to 100 hours.
  • the tapes were then uniaxially pressed at 10 GPa and heat treated at the same condition for 100 to 170 hours.
  • This processing route has been widely used by many groups.
  • Our modified processing route, the schedule II is schematically described in Figure 1. A short period of melt processing is used at the beginning of the second heat ' treatment in accordance with the process of the present invention.
  • the transport critical current density was determined from the current/voltage curve under magnetic field (H) varying from 0 to 1.2 T using a l ⁇ v/cm criterion.
  • Microstructural and compositional characterisation were performed with a JEOL JXA-840 Scanning Electron Microscope (SEM) and EM 400T and JEOL 2000-FX Transmission Electron Microscopy (TEM) both equipped with link systems AN1000 Energy Dispersive Spectrometers (EDS) .
  • FIG. 2 shows the dependence of the J c on magnetic field for Ag-clad tapes processed by the two schedules. It is evident that a short period of melt processing has a dramatic effect on the J c -H behaviour. At 77 K and
  • schedule I tape contains large particle impurity phase and pores.
  • schedule II tape appears very dense and contains no large impurity particles.
  • the density of schedule I tape is estimated to be 90% whereas the density for schedule II tape is 98%.
  • the high density and uniform distribution of the small impurity particles obtained from the melt processing may be responsible for the significant improvement in the weak link structure in the schedule II tape.
  • the superconducting composites were prepared by the same process as for Example 1, the schedule II tapes having a partial melt process applied.
  • Figure 5 shows the dependence of J c on the magnetic field for the partial melt processed tapes (A-C) and the SSR processed tapes (D-F) . It is seen that the partial melt processed tapes exhibit a 3- to 5-fold enhancement at 77K and 0 T and a 6- to 8-fold enhancement at 77K and 1 T in the J c , over the SSR processed tapes.
  • a J c of 40,000 A/cm 2 at 77K and 0 T, 25,000 A/cm 2 at 77K and 0.1 T, and 9,000 A/cm 2 at 77K and IT has been achieved in the partial melt processed tapes. Especially in the low magnetic field regime, the J c for the partial melt processed tapes drops much more slowly than that for the SSR processed tapes.
  • J c for the SSR processed tapes loses more than 70% to 80% of its zero field values at 0.1 T whereas J c for the partial melt processed tapes loses 25% to 35% of its zero field value inn the same field, indicating a significant improvement in the weak links structure through the partial melt.
  • the partial melt tapes showed an extended plateau from 0.1 to 1 T. This indicates that the partial melt process also improves the intragrain pinning of tape samples.
  • Figure 6 shows ' the irreversibility lines (IL) for schedule I and II tapes determined from the loss peak in the "X" part (T_) .
  • AC susceptibility measurements were conducted at a fixed AC of 0.35 Oe and fixed frequency of 1000 Hz. It is seen that the IL for tape A is positioned at higher temperature than that for tape E, indicating that short period melt processing effectively enhanced the flux pinning in the tape A.
  • Figure 7 compares the dislocation densities for melt-process tape (A) and normally sintered sample (G) .
  • Tape A has a density of dislocations of 10 10 to 10 11 lines/cm 2 , which is one or two orders of magnitude higher than that of normally sintered samples. This density is comparable with the density of the magnetic flux lines in the materials.
  • the flux lines in the high T c superconductors are estimated at a spacing of 30 nm in a field of 2 T.
  • the high density of dislocations with distorted vicinities form extended normal regions on atomic scale which may act as.potentially effective pinning sites for the flux lines on a large scale, contributing to the improved J c - H characteristic on the schedule II tapes.
  • the calcined powders were then sintered at temperatures between 800°C to 840°C for 10 to 30 hours and ground into fine powders through ball milling.
  • the resultant powders were pressed into bars of 8 mm diameter and loaded into silver tubes, drawn into wires and inally rolled into taped with typical size of 25 mm in length and 2-3 mm in width were cut from the long rolled wire and sintered in a furnace at 830°C for 80 hours in air.
  • X-ray diffraction was carried out to identify the phase distribution of the oxide core in superconducting tape at this tape using a SIEMENS D5000 Diffractometre.
  • T c Measurement was also performed using DC four probe technique at temperature range from 77 K to 300 K.
  • the tape samples were heat- treated by a partial melt process, in accordance with the present invention, i.e., raising temperature to melting temperatures varying from 848°C to 875°C at 120°C/min. , holding at the melting temperature for 15 minutes (SPPM step) , decreasing temperature to 834°C at 120°C/min, soaking for 3 hours and then cooling to room temperature in the furnace.
  • some tapes were sintered at 864°C for a long period of 3 to 30 hours at the melting step (long-period melt process) .
  • XRD analyses and SEM observation using JEOL JSM-840 scanning electron microscope with a Link system AN1000 energy dispersive spectrometer (EDS) , were carried out to determine the phase distribution and morphology.
  • the specimens for XRD were prepared by cutting a small section of the tape and peeling off the upper Ag sheath.
  • the polished cross section of the oxide core of the tape was used for SEM study.
  • the sample tapes were pressed again and annealed at 834°C for 80 to 160 hours in air. Some samples were further annealed at 834°C in air for additional 80 hours in order to determine the effect of annealing time on the recovery of the (2223) phase.
  • the phase distribution and microstrueture of the tape after post-annealing were investigated by XRD, SEM and EDS.
  • the critical current density (J c ) in the presence of magnetic field was measured at 77K by the four-point probe D.C. technique using a criterion of 1 ⁇ /cm.
  • FIG. 8 shows the XRD patterns for samples partial melt- treated at different temperatures. It is evident that the high T c phase (2223) inside oxide core of superconducting tapes was very sensitive to the melting temperatures. The (2223) phase in those tapes which were melted at temperatures above 859°C were complete decomposed into low-T c phase (2212) , while for the samples melted at temperatures below 853°C the (2223) phase remained unchanged. At the melting temperatures between 854°C and 859°C, the (2223) and (2212) phases co ⁇ existed. The ratio of (2223) to (2212) phase in those samples decreased with increasing melting temperatures as shown in Figure 9.
  • Figure 11 shows that the high-T c (2223) phase which had been partially decomposed during the partial melt at 855°C for 15 minutes was fully recovered by a post-annealing at 834°C for 80 hours. But, for the longer-period melted samples, the (2223) phase recovery cannot be achieved through post-annealing.
  • Figures 12, 13 and 14 are the XRD pattens of samples which were sintered at 864°C for 3, 10 and 30 hours respectively, followed by annealing at 834°C for 80 hours in air.
  • EDS analysis was undertaken.
  • Figure 16(b) shows that the matrix (2223) phase in an as-melted tape was decomposed into (2212) phase and some small, dispersed non-superconducting Ca 2 Cu0 4 and CuO particles. Meanwhile, the grains of the major phase became better aligned with c-axis perpendicular to the tape surface and grain size increased.
  • Figures 17(a) and 17(b) are the SEM photographs of samples after melting at 864°C for 30 hours and after subsequent annealing at 834°C for 80 hours, respectively.
  • the matrix consists of grey background phase and large darker inclusions. The grain sizes of both the major phase and inclusions were much larger than that of SPPM processed samples.
  • the EDS analysis confirmed that the grey phase was (2212) grains and the darker phases were Sr-Ca-Cu-0. It is noteworthy that two Sr-Ca-Cu-0 phases were observed.
  • the atomic ratio of Sr, Ca and Cu are found by EDS analyses to be 1.0:7.6:4.4 for the dark one and 1.0:0.87:3.04 for the brighter one.
  • Figure 17(b) shows that after post- annealing, the (2212) still was the major phase and the large Sr-Ca-Cu-0 particles remained.
  • additional 80 hour annealing was performed for some long-period melted samples.
  • the XRD patterns showed that the microstructure did not have significant change inside the oxide core of tapes although these tapes were post-annealed for 160 hours, this indicates that unlike the SPPM process in which the sampler (2212) grains could react easily with the finely dispersed

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  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)

Abstract

La présente invention concerne un matériau composite supraconducteur revêtu/dopé à l'argent, du système supraconducteur Bi-Pb-Sr-Ca-Cu-O, et un procédé de fabrication du matériau composite revêtu/dopé à l'argent. En introduisant une étape de chauffage à une température légèrement supérieure à la normale pendant un temps court, la phase prédominante 2223 de haute Tc (température de transition) du matériau composite est décomposée en une phase prédominante 2212 pendant le procédé de formation. La phase de haute Tc est ensuite récupérée par une étape de chauffage supplémentaire à une température plus basse, avec une proportion minoritaire de phase 2212 distribuée de manière substantiellement uniforme à travers le matériau composite. Le résultat de ce procédé est un matériau composite possédant une Jc améliorée (densité de courant critique) dans les champs magnétiques.
PCT/AU1993/000180 1992-04-27 1993-04-27 Materiau composite supraconducteur a revetement d'argent WO1993022799A1 (fr)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994023459A1 (fr) * 1993-04-01 1994-10-13 American Superconductor Corporation Traitement ameliore de supraconducteurs d'oxyde
EP0630873A1 (fr) * 1993-06-23 1994-12-28 Hoechst Aktiengesellschaft Procédé pour augmenter la force de pinning d'une céramique supraconductrice Bi-Pb-Sr-Ca-Cu-O
WO1996019417A1 (fr) * 1994-12-20 1996-06-27 Siemens Aktiengesellschaft Procede de fabrication d'un supraconducteur allonge presentant une phase bismuth a temperature de transition elevee, et supraconducteur fabrique suivant ce procede
WO1997017733A1 (fr) * 1995-11-07 1997-05-15 American Superconductor Corporation Traitement de cables en oxyde supraconducteurs
US5635456A (en) * 1993-04-01 1997-06-03 American Superconductor Corporation Processing for Bi/Sr/Ca/Cu/O-2223 superconductors
FR2764727A1 (fr) * 1997-06-12 1998-12-18 Alsthom Cge Alcatel Procede de texturation d'un conducteur supraconducteur htc, conducteur realise selon un tel procede

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PATENT ABSTRACTS OF JAPAN, C-913, page 100; & JP,A,3 265 523 (SUMITOMO ELECTRIC LTD), 16 March 1990. *
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Cited By (16)

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Publication number Priority date Publication date Assignee Title
US6436876B1 (en) 1993-04-01 2002-08-20 American Superconductor Corporation Processing of oxide superconductors
US5635456A (en) * 1993-04-01 1997-06-03 American Superconductor Corporation Processing for Bi/Sr/Ca/Cu/O-2223 superconductors
US5661114A (en) * 1993-04-01 1997-08-26 American Superconductor Corporation Process of annealing BSCCO-2223 superconductors
AU696752B2 (en) * 1993-04-01 1998-09-17 American Superconductor Corporation Improved processing of oxide superconductors
US6284712B1 (en) 1993-04-01 2001-09-04 Alexander Otto Processing of oxide superconductors
US5994275A (en) * 1993-04-01 1999-11-30 American Superconductor Corporation Processing of oxide superconductors
WO1994023459A1 (fr) * 1993-04-01 1994-10-13 American Superconductor Corporation Traitement ameliore de supraconducteurs d'oxyde
EP0630873A1 (fr) * 1993-06-23 1994-12-28 Hoechst Aktiengesellschaft Procédé pour augmenter la force de pinning d'une céramique supraconductrice Bi-Pb-Sr-Ca-Cu-O
US6194352B1 (en) 1994-01-28 2001-02-27 American Superconductor Corporation Multifilament composite BSCCO oxide superconductor
US6074991A (en) * 1994-12-20 2000-06-13 Siemens Aktiengesellschaft Process for producing an elongated superconductor with a bismuth phase having a high transition temperature and a superconductor produced according to this process
WO1996019417A1 (fr) * 1994-12-20 1996-06-27 Siemens Aktiengesellschaft Procede de fabrication d'un supraconducteur allonge presentant une phase bismuth a temperature de transition elevee, et supraconducteur fabrique suivant ce procede
AU729277B2 (en) * 1995-11-07 2001-02-01 American Superconductor Corporation Processing of oxide superconductor cables
WO1997017733A1 (fr) * 1995-11-07 1997-05-15 American Superconductor Corporation Traitement de cables en oxyde supraconducteurs
US6013608A (en) * 1997-06-12 2000-01-11 Alcatel Process for texturing an HTc superconductor and superconductor made by the process
EP0886327A1 (fr) * 1997-06-12 1998-12-23 Alcatel Procédé de texturation d'un conducteur supraconducteur HTC, conducteur réalisé selon un tel procédé
FR2764727A1 (fr) * 1997-06-12 1998-12-18 Alsthom Cge Alcatel Procede de texturation d'un conducteur supraconducteur htc, conducteur realise selon un tel procede

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