Improvement of superconducting properties of Bi-2212 round wire and primary test results of large capacity Rutherford cable

Hasegawa, Takeshi; Ohtani, N.; Koizumi, Tsutomu; Aoki, Yuji; Nagàya, Shigeo; Hirano, Naoki; Motowidlo, L. R.; Sokolowski, R.S.; Scanlan, R.M.; Dietderich, D.R.; Hanai, S.

doi:10.1109/77.919702

Cited by 70 publications

(38 citation statements)

References 3 publications

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“…The main attractiveness of Bi-2212, besides the highfield properties recalled above, is that it is available as a round wire, and can thus be formed into a Rutherford cable, as has been consistently demonstrated since the 1990s [113][114][115][116]. The record J E is around 500 A/mm 2 at 20 T, 4.2 K in a 1-m-long round wire [117] (Fig.…”

Section: Bi-2212mentioning

confidence: 86%

“…The concept of Rutherford cables can be easily applied to any material that comes in the form of round wires, and it has been extended to round Bi-2212 HTS wires [113][114][115][116]. Further cable concepts, such as the Roebel bar, or tape assemblies around a stabilizer core or tube, discussed earlier, are in an early stage of development and have not yet found an accelerator application.…”

Section: Superconducting Materials and Conductors: Fabrication And LImentioning

confidence: 99%

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Superconducting Materials and Conductors: Fabrication and Limiting Parameters

Bottura

Godeke

2012

Rev. Accl. Sci. Tech.

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Superconductivity is the technology that enabled the construction of the most recent generation of high-energy particle accelerators, the largest scientific instruments ever built. In this review we trace the evolution of superconducting materials for particle accelerator magnets, from the first steps in the late 1960s, through the rise and glory of Nb-Ti in the 1970s, till the 2010s, and the promises of Nb 3 Sn for the 2020s. We conclude with a perspective on the opportunities for high-temperature superconductors (HTSs). Many such reviews have been written in the past, as witnessed by the long list of references provided. In this review we put particular emphasis on the practical aspects of wire and tape manufacturing, cabling, engineering performance, and potential for use in accelerator magnets, while leaving in the background matters such as the physics of superconductivity and fundamental material issues.

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Section: Bi-2212mentioning

confidence: 86%

Section: Superconducting Materials and Conductors: Fabrication And LImentioning

confidence: 99%

Superconducting Materials and Conductors: Fabrication and Limiting Parameters

Bottura

Godeke

2012

Rev. Accl. Sci. Tech.

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“…It has been already demonstrated that such properties make Bi-2212 a very competitive conductor for high field applications (> 20 T) such as magnets for nuclear magnetic resonance or accelerators [4][5][6][7][8][9], however, in this context, an enhancement of J C of two or three times seems to be still needed to boost the successful use of this superconductor in such applications. This aim has driven the work of several groups, especially in USA -where, besides the research labs, Oxford Superconducting Technology (OST) is a company leader on Bi-2212 round wire fabrication -and in Japan and Korea.…”

Section: Introductionmentioning

confidence: 99%

Large critical current density improvement in Bi-2212 wires through the groove-rolling process

Malagoli¹,

Bernini²,

Braccini³

et al. 2013

Supercond. Sci. Technol.

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Recently the interest about Bi-2212 round wire superconductor for high magnetic field use has been enhancing despite the fact that an increase of the critical current is still needed to boost its successful use in such applications. Recent studies have demonstrated that the main obstacle to current flow, especially in long wires, is the residual porosity inside these Powder-In-Tube processed conductors which develops in bubbles-agglomeration when the Bi-2212 melts. Through this work we tried to overcome this issue acting on the wire densification by changing the deformation process. Here we show the effects of groove-rolling versus drawing process on the critical current density J C and on the microstructure. In particular, groove-rolled multifilamentary wires show a J C increased by a factor of about 3 with respect to drawn wires prepared with the same Bi-2212 powder and architecture. We think that this approach in the deformation process is able to produce the required improvements both because the superconducting properties are enhanced and because it makes the fabrication process faster and cheaper.

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“…The filament mass density was calculated by assuming the density of silver and silver alloy to be 10.49 g/cm 3 . X-ray tomographic 2 . More details about the tomography set-up can be found in [11].…”

mentioning

confidence: 99%

Reduction of Gas Bubbles and Improved Critical Current Density in Bi-2212 Round Wire by Swaging

Jiang

Miao²,

Huang³

et al. 2013

IEEE Trans. Appl. Supercond.

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Bi-2212 round wire is made by the powder-in-tube technique. An unavoidable property of powder-in-tube conductors is that there is about 30% void space in the as-drawn wire. We have recently shown that the gas present in the as-drawn Bi-2212 wire agglomerates into large bubbles and that they are presently the most deleterious current limiting mechanism. By densifying short 2212 wires before reaction through cold isostatic pressing (CIPping), the void space was almost removed and the gas bubble density was reduced significantly, resulting in a doubled engineering critical current density (J E ) of 810 A/mm 2 at 5 T, 4.2 K. Here we report on densifying Bi-2212 wire by swaging, which increased J E (4.2 K, 5 T) from 486 A/mm 2 for asdrawn wire to 808 A/mm 2 for swaged wire. This result further confirms that enhancing the filament packing density is of great importance for making major J E improvement in this roundwire magnet conductor. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Abstract-Bi-2212 round wire is made by the powder-in-tube technique. An unavoidable property of powder-in-tube conductors is that there is about 30% void space in the as-drawn wire. We have recently shown that the gas present in the asdrawn Bi-2212 wire agglomerates into large bubbles and that they are presently the most deleterious current limiting mechanism. By densifying short 2212 wires before reaction through cold isostatic pressing (CIPping), the void space was almost removed and the gas bubble density was reduced significantly, resulting in a doubled engineering critical current density (J E ) of 810 A/mm 2 at 5 T, 4.2 K. Here we report on densifying Bi-2212 wire by swaging, which increased J E (4.2 K, 5 T) from 486 A/mm 2 for as-drawn wire to 808 A/mm 2 for swaged wire. This result further confirms that enhancing the filament packing density is of great importance for making major J E improvement in this round-wire magnet conductor.

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Improvement of superconducting properties of Bi-2212 round wire and primary test results of large capacity Rutherford cable

Cited by 70 publications

References 3 publications

Superconducting Materials and Conductors: Fabrication and Limiting Parameters

Superconducting Materials and Conductors: Fabrication and Limiting Parameters

Large critical current density improvement in Bi-2212 wires through the groove-rolling process

Reduction of Gas Bubbles and Improved Critical Current Density in Bi-2212 Round Wire by Swaging

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