Multifilament niobium-tin conductors

Murase, S.; Koizumi, M.; Horigami, O.; Shiraki, H.; Koike, Yasuhiro; Suzuki, Eriko; Ichihara, M.; Nakane, Fumoto; Aoki, Nobuo

doi:10.1109/tmag.1979.1060198

Cited by 35 publications

(7 citation statements)

References 7 publications

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“…Early on, geometrically similar conductors were fabricated by Murase and associates [7]. The phase formation sequence was presumably similar to the present case, but the layer growth and lower J c may indicate a lower Sn level was present in the core.…”

Section: Introductionsupporting

confidence: 66%

“…The general idea of tube type conductors, where Cu and Sn are inserted into Nb tubes, has been pursued before [7][8][9][10][11], and these conductors do have some similarities to powderin-tube (PIT) strands (as well as differences) [12][13][14][15][16][17][18][19][20][21]. Early on, geometrically similar conductors were fabricated by Murase and associates [7].…”

Section: Introductionmentioning

confidence: 99%

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COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

Bhartiya¹,

Sumption²,

Peng³

et al. 2010

AIP Conference Proceedings

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A15 stoichiometry was investigated and compared for two different Nb 3 Sn strand designs, "tube type" and high-performance, distributed-barrier RIT type. The focus of the study was to attain fine grain A15 with maximal Sn stoichiometry. Tube type conductors were compared to RIT conductors, each after the application of two-step HTs with plateaus ranging from 615°C to 675°C for various times. The resulting transport values were compared to those arising from standard HTs, namely 3476 A/mm 2 for the RIT conductors and 2231 A/mm 2 for the tube type conductors. The influence of strand geometry and reaction route was related to the resulting A15 stoichiometries. Short sections of strand were encapsulated and then HT, after which SEM (BSE) and EDS were used to observe the structures and obtain Sn concentration profiles. Fractography was performed to investigate the effect of a two-step reaction on the morphology, the ratio of coarse/fine grain area and grain size of fine grain A15.

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Section: Introductionsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

Bhartiya¹,

Sumption²,

Peng³

et al. 2010

AIP Conference Proceedings

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“…Bruker-EAS at present. Also in the 1970s another Nb3Sn wire manufacturing technology emerged, which produces subelements by inserting Cu-clad Sn rods into Nb (or Nb-7.5wt.%Ta) tubes [45,46].…”

Section: Review Of Nb3sn Conductor Developmentmentioning

confidence: 99%

A review and prospects for Nb₃Sn superconductor development

2017

Supercond. Sci. Technol.

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Nb3Sn superconductors have significant applications in constructing high-field (> 10 T) magnets. This article briefly reviews development of Nb3Sn superconductor and proposes prospects for further improvement. It is shown that significant improvement of critical current density (Jc) is needed for future accelerator magnets. After a brief review of the development of Nb3Sn superconductors, the factors controlling Jc are summarized and correlated with their microstructure and chemistry. The non-matrix Jc of Nb3Sn conductors is mainly determined by three factors: the fraction of current-carrying Nb3Sn phase in the non-matrix area, the upper critical field Bc2, and the flux-line pinning capacity. Then prospects to improve the three factors are discussed respectively. An analytic model was developed to show how the ratios of precursors determine the phase fractions after heat treatment, based on which it is predicted that the limit of current-carrying Nb3Sn fraction in subelements is ~65%. Then, since Bc2 is largely determined by the Nb3Sn stoichiometry, a thermodynamic/kinetic theory was presented to show what essentially determines the Sn content of Nb3Sn conductors. This theory explains the influences of Sn sources and Ti addition on stoichiometry and growth rate of Nb3Sn layers. Next, to improve flux pinning, previous efforts in this community to introduce additional pinning centers (APC) to Nb3Sn wires are reviewed, and an internal oxidation technique is described.Finally, prospects for further improvement of non-matrix Jc of Nb3Sn conductors are discussed, 2 and it is seen that the only opportunity for further significantly improving Jc lies in improving the flux pinning.

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“…The conductor, produced by the Showa Electric Wire and Cable Company, was a rectangular monolithic wire, 2 mm wide and 1 mm thick, with 258 niobium tubes filled with tin and distributed in a copper matrix (Murase et al 1979). The conductor cross-section is shown in Fig.…”

Section: Kek-toshiba Small-scale Nb 3 Sn Dipole (1980)mentioning

confidence: 99%

“…18 Cross-section of the small-scale KEK-Toshiba Nb 3 Sn dipole (Modified fromMurase et al 1979): 1aluminum pipe; 2epoxy impregnated glass tape; 3 -SUS 316 L stainless-steel pole blocks; 4coil inner layer; 5coil outer layer; 6 -SUS 304 L stainless-steel support tube; 7cooling channel…”

mentioning

confidence: 99%

Nb3Sn Accelerator Magnets: The Early Days (1960s–1980s)

Rossi

Zlobin

2019

Nb3Sn Accelerator Magnets

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Since Nb 3 Sn became available in the form of relatively long tapes in the early 1960s, it was considered for high-field magnets thanks to its high upper critical magnetic field and critical temperature. This chapter is a review of the effort accomplished by the community in the first 25 years of development of Nb 3 Sn accelerator magnets, and an attempt to understand why it took so long before this technology became successful. IntroductionDiscovery and major advancements in the understanding and development of practical type II superconductors in the 1950s and 1960s made it possible to employ them in superconducting magnets, particularly, in accelerator magnets used for steering charged particle beams. The superconducting properties of Nb 3 Sn were discovered in the early 1960s, and soon it was available in form of tapes (or ribbons) produced by the surface diffusion process. Shortly afterwards an alternative concept based on solid-state diffusion was introduced. This principle has been used since the 1970s to fabricate Nb 3 Sn composite wires by the so-called bronze route. In 1974 the internal tin (IT) process was developed, which allowed overcoming the limitation of the bronze method to reach a high critical current density J c due to the limited content of tin in bronze. The availability of IT composite wires eventually proved to be a key asset for high-field Nb 3 Sn magnet research and development (R&D) for accelerators. The year-by-year history of Nb 3 Sn wire development can be found in Foner and Schwartz (1981).

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Multifilament niobium-tin conductors

Cited by 35 publications

References 7 publications

COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

A review and prospects for Nb₃Sn superconductor development

Nb3Sn Accelerator Magnets: The Early Days (1960s–1980s)

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Multifilament niobium-tin conductors

Cited by 35 publications

References 7 publications

COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

A review and prospects for Nb3Sn superconductor development

Nb3Sn Accelerator Magnets: The Early Days (1960s–1980s)

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Product

Resources

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A review and prospects for Nb₃Sn superconductor development