Superconducting joints for silver-clad BSCCO tapes

Huang, Jianfeng; Jammy, R.; Iyer, A. N.; Haldar, Pradeep

doi:10.1007/bf02652984

Cited by 10 publications

(6 citation statements)

References 7 publications

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“…The standard method for fabricating joints in mono-filamentary Ag/Bi-2223 PIT tapes was first employed by Tkaczyk et al [93]. It involves exposing the filament surface in a partially processed tape by mechanically removing [93] or chemically etching [15,[94][95][96][97][98] the Ag sheath from one side of the tape. The exposed ceramic cores are placed in contact with one another (usually in lap joint geometry) and uniaxially pressed under high pressure to cold-weld the Ag sheath and seal the joint.…”

Section: Joints Between Biscco Superconductorsmentioning

confidence: 99%

“…The joined tape is then subjected to an extensive thermomechanical treatment similar that used for the conductor itself. Joints with CCR values between 25% and 90% have been fabricated using this process, with the current carrying ability of the joint depending on the joint geometry [15,95], pressure used in the thermomechanical process [15], heat treatment time [94,96,98] and annealing process prior to joining [93]. In some cases the critical current within the joint region is found to be higher than the bulk tape owing to the thicker cross-section of the core in the joint.…”

Section: Joints Between Biscco Superconductorsmentioning

confidence: 99%

“…In some cases the critical current within the joint region is found to be higher than the bulk tape owing to the thicker cross-section of the core in the joint. However, the current across the joint tends to be limited by the transition regions (where the parent wires enter/exit the joint), in which it is common to find either microcracking as a result of the extensive cold pressing [96] or, in lap joint geometry, intrusion of the silver cladding narrowing the cross-section [15,93,95] (as shown in figure 15).…”

Section: Joints Between Biscco Superconductorsmentioning

confidence: 99%

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Persistent current joints between technological superconductors

Brittles

Mousavi

Grovenor

et al. 2015

Supercond. Sci. Technol.

122

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Persistent current joints are crucial components of superconducting magnets—enabling the production of the high and ultra-stable magnetic fields required, for instance, for magnetic resonance measurements. At this critical juncture when persistent mode magnets containing commercial high temperature superconductors may soon become a reality, it is of value to take stock and evaluate current challenges faced in the field of jointing. This paper provides a review of progress made to date on the production and characterization of joints between the five major technological superconductors—NbTi, Nb3Sn, MgB2, BiSCCO and REBCO, including the materials that are used to make these joints.

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Section: Joints Between Biscco Superconductorsmentioning

confidence: 99%

Section: Joints Between Biscco Superconductorsmentioning

confidence: 99%

Section: Joints Between Biscco Superconductorsmentioning

confidence: 99%

See 1 more Smart Citation

Persistent current joints between technological superconductors

Brittles

Mousavi

Grovenor

et al. 2015

Supercond. Sci. Technol.

122

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“…12 One requirement for joint fabrication is the need to expose the BSCCO core to create a truly superconductingjoint.Mechanicalmethods have been utilized in the past to peel away the silver sheath, but such methods result in damage to the core and, thus, in reduced Ie valuesP A chemical-etching technique that allows exposure of the BSCCO core with- out mechanical damage has been developed. 12 monofilament tapes) and graded joints (for multifilament tapes) were formed by carefully aligning and pressing the two tapes together, followed by a 50 hour heat treatment. The joined tapes were then subjected to a series of thermomechanical treatments that consisted of uniaxial pressing and heat treatment' as done in the processing of a regular tape without joints.…”

Section: Superconducting Jointsmentioning

confidence: 99%

Advances in processing and characterizing Bi-based superconductors

Jammy

Chudzik

Iyer

et al. 1996

JOM

Self Cite

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Advances in the processing and fabrication of mono-and multifilament Bi-2223/ 2212 high-critical-temperature superconductors by the powder-in-tube technique continue to bring these materials closer to commercial applications. Consistently high critical-current densities (J) greater than 10 4 A/ cm 2 have been achieved along the entire length of a 1,260 m long, 37 filament Bi-2223 tape. Pancake-shaped coils, test magnets, and a prototype transformer were fabricated and characterized from such long conductors. Record high fields have been generated in prototype test magnets operated as inserts in the high background fields of conventional low-critical-temperature magnets. With an eye toward commercialization, this article reviews some of the recent advances in the processing and characterization of bismuthbased tapes. INTRODUCTIONAs a preliminary step toward realizing the numerous potential applications of high-critical-temperature (high-T) superconductor materials, significant effort is underway to develop long-length wires and tapes with these materials. The powder-in-tube (PIT) process for the Bi-Sr-Ca-Cu-O (BSCCO) system of superconductors with silver and its alloys as a sheathing material is a promising and industrially scalable technique for fabricating long-length superconductors. Although considerable progress has been made in the past few years in fabricating PIT tapes and enhancing their critical-current density (J), the complexities l -II involved in obtaining phase purity, crystalline orientation, good intergranular connectivity, and sufficient mechanical strength in a brittle multicomponent oxide like BSCCO have long impeded the successful commercialization of high-Te superconductors.Many applications require continuous lengths of tape on the order of one kilometer with uniform electrical properties.3-11 Although tape length can be customized for specific applications, many applications (as in subcoil interconnections in large magnets) require superconducting joints between the tapesP-14 Because high-Tesuperconductors will be subjected to mechanical stresses-axial and bending stresses 1996 October • JOM during fabrication and service and magnetic-field-induced (Lorentz) stresses during operation-the electrical properties of these conductors under strain are an important engineering issue. IS

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“…In the literature, most of the research that has been carried out involves a superconducting-joint method for BSCCO monofilamentary tape [9][10][11][12][13]. It was reported that critical current ratio (CCR) and strength were degraded in the transition region because of the nonuniform microstructure, which in turn resulted in reduction of these properties in the entire jointed tape.…”

Section: Introductionmentioning

confidence: 99%

A superconducting joint between Bi Pb Sr Ca Cu O multifilamentary tapes

Kim¹,

Joo²

2002

Supercond. Sci. Technol.

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We evaluated the effects of the joining process on the electrical properties of Bi–Pb–Sr–Ca–Cu–O (BSCCO) multifilamentary jointed tapes. In the process, a 37-filament BSCCO tape was fabricated by the powder-in-tube technique and the tapes were joined by a superconducting-joint method. To improve the filament connectivity between the tapes, the contacting surface of each tape was modified to a stepped shape, and the joined region was uniaxially pressed at 1000–2500 MPa.The critical current ratio (CCR) and n-value of the jointed tape were evaluated as a function of uniaxial pressure and number of steps in the contacting region. It was observed that those properties were dependent on the number of steps, but were almost independent of uniaxial pressure. The highest CCR and n-value for the jointed tape were 61.9% and 5.1, respectively, obtained by optimizing the number of steps and the pressure. It is believed that the highest values for the jointed tape resulted because the contacting area (the ‘window’) increased and more tape filaments were connected to each other in the joined region. The microstructural evolution was also evaluated and correlated to the resultant properties of the jointed tape.

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Superconducting joints for silver-clad BSCCO tapes

Cited by 10 publications

References 7 publications

Persistent current joints between technological superconductors

Persistent current joints between technological superconductors

Advances in processing and characterizing Bi-based superconductors

A superconducting joint between Bi Pb Sr Ca Cu O multifilamentary tapes

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