Development of APC Nb-Ti composite conductors at Supercon, Inc

Rudziak, M.K.; Seuntjens, J. M.; Renaud, C.V.; Wong, Terence Kin Shun; Wong, J.

doi:10.1109/77.402906

Cited by 18 publications

(9 citation statements)

References 4 publications

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“…However, the Ni pin volume was only 2%, in contrast to the optimum nonmagnetic pin volumes of 20%-30%. [3][4][5][6][7][8] These results and those for our other wires that contained Ni pins, indicate that wires with larger volumes of Ni may have even larger J c 's.…”

supporting

confidence: 53%

“…1,2 In recent years, researchers have also used a second method, artificial pinning centers ͑APCs͒, to produce pins in NbTi wires. [3][4][5][6][7][8] Artificial pins are placed in the NbTi at a macroscopic size and then the composite wire is repeatedly drawn to produce nanometer pin thickness and spacing. The artificial pin materials used have been either Nb or Ti ͑lowfield superconductors͒, or Cu ͑a normal metal͒.…”

mentioning

confidence: 99%

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Ferromagnetic artificial pinning centers in superconducting Nb0.36Ti0.64 wires

Rizzo

Wang

Prober

et al. 1996

Applied Physics Letters

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We used ferromagnetic artificial pinning centers in superconducting NbTi wires to achieve a large critical current density (J c) in a magnetic field. Four wires were fabricated that contained nanometer-sized arrays of Ni or Fe pins inside micron-sized filaments of Nb 0.36 Ti 0.64 alloy. A ferromagnetic pin volume of only 2% Ni produced J c 's ͑e.g., 2500 A/mm 2 at 5 T, 4.2 K͒ that were comparable to those of commercial wires that have a pin volume of ϳ20% Ti. We conclude that ferromagnetic artificial pins are more effective than nonmagnetic pins for a given volume percent.

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supporting

confidence: 53%

mentioning

confidence: 99%

Ferromagnetic artificial pinning centers in superconducting Nb0.36Ti0.64 wires

Rizzo

Wang

Prober

et al. 1996

Applied Physics Letters

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“…This is 50% higher than conventionally processed Nb-Ti wire. Even greater improvements of up to 100% at 2 T over conventional Nb-Ti has been demonstrated by groups in both academia [2], [3] and industry [4]- [6]. But, these outstanding low to mid field properties have been tempered by lower properties in applied magnetic field above 5 T, where conventionally processed wires have outperformed APC designs [7].…”

Section: Introductionmentioning

confidence: 93%

The pinning strength and upper critical fields of magnetic and nonmagnetic artificial pinning centers in Nb47/sup W//oTi wires

Motowidlo

Rudziak

Wong

2003

IEEE Trans. Appl. Supercond.

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Nb47 /oTi wire samples were fabricated with copper 12Vol%, 6Ni/6Cu, and 8Ni/4Cu artificial pinning centers (APC). The optimum diameter of the "island" pins was 10 to 12 nm at final wire size. Low temperature heat treatment of sample wires was performed at final diameters to form alloy pins. The upper critical field, 2 , irreversibility field, , and the critical current density, , were measured at 4.2 K. Magnetization measurements showed highest 2 of 11 T and of 9.8 T in the best APC wire. In addition, significant improvement in was obtained at all fields above 5 T compared to past APC designs. At 5 T, s up to 5034 A/mm 2 were obtained by transport measurements. Field emission scanning electron microscopy (FESEM) of the pins at near final wire diameters suggest a new feature. The possible presence of voids formed on the outside of each pin as a result of nickel and copper inter-diffusion (Kirkendall Effect) from low temperature heat treatment.Index Terms-Artificial pinning center, critical current, flux pinning, Nb-Ti wire, proximity effect, upper critical field.

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“…A wide variety of diffused-layer composites were explored [68][69][70][71][72], which used coiled foils (like a jelly-roll) or concentric tubes to arrange the layers. A fairly broad overall composition range was demonstrated with minor modification of the basic process [68].…”

Section: Diffused-layer Apc Compositesmentioning

confidence: 99%

Advances in high-field superconducting composites by addition of artificial pinning centres to niobium-titanium

Cooley

Motowidlo

1999

Supercond. Sci. Technol.

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Artificial pinning-centre (APC) niobium-titanium composites attain critical current density J c values higher than 4000 A mm −2 at 5 T, 4.2 K, surpassing the barrier reached by the conventional Nb-Ti composite process. At 2 T APC composites achieve more than double the J c of conventional composites, making them particularly well suited for low-field applications. On the other hand, APC composites are inferior to conventional composites at 8 T, due to weak high-field pinning and reduced upper critical field. This review discusses fabrication techniques, microstructural development and superconducting and flux-pinning properties of APC composites. Key elements and underlying issues for achieving higher J c are identified and discussed in terms of the current state of the art.

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Development of APC Nb-Ti composite conductors at Supercon, Inc

Cited by 18 publications

References 4 publications

Ferromagnetic artificial pinning centers in superconducting Nb0.36Ti0.64 wires

Ferromagnetic artificial pinning centers in superconducting Nb0.36Ti0.64 wires

The pinning strength and upper critical fields of magnetic and nonmagnetic artificial pinning centers in Nb47/sup W//oTi wires

Advances in high-field superconducting composites by addition of artificial pinning centres to niobium-titanium

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