Behavior of MgB2 React &amp;amp; Wind Coils Above 10 K

Musenich, R.; Fabbricatore, P.; Farinon, S.; Grasso, G.; Greco, M.; Malagoli, Andrea; Marabotto, R.; Modica, M.; Nardelli, Davide; Siri, A. S.; Tassisto, M.; Tumino, A.

doi:10.1109/tasc.2005.849125

Cited by 35 publications

(33 citation statements)

References 9 publications

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“…O NLY a few years after the discovery of MgB magnet prototypes made of powder-in-tube (PIT) wires have become available [1], [2]. Unfortunately, the maximum field, which can be generated by these magnets is much smaller than that produced by NbTi or Nb Sn magnets.…”

Section: Introductionmentioning

confidence: 99%

Neutron Irradiation of SiC Doped and Magnesium Rich MgB$_{2}$ Wires

Eisterer

Schöppl

Weber

et al. 2007

IEEE Trans. Appl. Supercond.

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Monofilamentary SiC doped wires and multifilamentary wires made from magnesium-rich powders were exposed to thermal neutrons. The induced defects enhance the field, up to which the resistivity is zero ("irreversibility field") at 4.2 K (by about 1-2 T), and, therefore, reduce the field dependence of the critical current density. On the other hand, the transition temperature decreases from about 35 K to 32.5 K, thus restricting the beneficial effect of neutron irradiation to low temperatures. Changes of the critical current density are discussed in terms of changes of the fundamental superconducting parameters (condensation energy, upper critical field, anisotropy) and changes of the flux pinning properties.

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Section: Introductionmentioning

confidence: 99%

Neutron Irradiation of SiC Doped and Magnesium Rich MgB$_{2}$ Wires

Eisterer

Schöppl

Weber

et al. 2007

IEEE Trans. Appl. Supercond.

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“…Soltanian, Dou, et al, [14] Musenich et al [21] reported on pancake coils wound from tape which carried 347 A at 4.2 K in the coil and generated 0.75 T.…”

Section: Introductionmentioning

confidence: 99%

Solenoidal coils made from monofilamentary and multifilamentary MgB₂strands

Sumption¹,

Bhatia²,

Buta³

et al. 2005

Supercond. Sci. Technol.

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Three solenoids have been wound and with MgB 2 strand and tested for transport properties. One of the coils was wound with Cu-sheathed monofilamentary strand and the other two with a seven filament strand with Nb-reaction barriers, Cu stabilization, and an outer monel sheath. The wires were first S-glass insulated, then wound onto an OFHC Cu former. The coils were then heat treated at 675°C/30 min (monofilamentary strand) and 700°C/20 min (multifilamentary strand). Smaller (1 m) segments of representative strand were also wound into barrel-form samples and HT along with the coils. After HT the coils were epoxy impregnated. Transport J c measurements were performed at various taps along the coil lengths. Measurements were made initially in liquid helium, and then as a function of temperature up to 30 K. Homogeneity of response along the coils was investigated and a comparison to the short sample results was made. Each coil contained more than 100 m of 0.84-1.01 mm OD strand. One of the 7 strand coils reached 222 A at 4.2 K, self field, with a J c of 300 kA/cm 2 in the SC and a winding pack J e of 23 kA/cm 2 .At 20 K these values were 175 kA/cm 2 and 13.4 kA/cm 2 . Magnet bore fields of 1.5 T and 0.87 T were achieved at 4.2 K and 20 K, respectively. The other multifilamentary coil gave similar results. Keywords Strand FabricationThe continuous tube forming/filling (CTFF) process was used to produce Table 1. For further details on these multifilamentary strands, see [24]. Coil Winding, Heat Treatment, Epoxy ImpregnationThe former was solenoidal and made from OFHC Cu. The strands for all three coils were insulated with S-glass insulation. The coils had from 364 to 538 turns of strand, see Table 2. Cu-1 was HT for 675°C/30 min, while NbCu-7A and B were HT for 700°C/20 min. The ramp up time was 2.5 h and the ramp-down time was approximately 5-6 h, and all HT were performed under flowing Ar. Coils Cu-1 and NbCu-7A were vacuum impregnated with mixed Stycast 1266 epoxy heated to 40°C. NbCu-7B was merely dipped into degassed epoxy (40°C). After removal from the epoxy bath the coil curing was performed in air (at room temperature). Total curing time was estimated at 6-12 h. Coil Measurement and ResultsTransport properties of the coils were measured in a LHe cryostat (Figure 1 shows Cu-1 mounted and ready for insertion). The 4.2 K measurements were performed in liquid He, while higher temperature measurements were made as the coil warmed up.Two Cernox temperature sensors were mounted on the coil, one on the top and one on the bottom. The temperature difference across the coil was never greater than 0.3 K. Voltage taps were placed an various places along the winding. The typical distance between successive taps was about 14-20 m. The field was measured with a cryogenic hall probe and a Bell gaussmeter calibrated to achieve a 2% or better accuracy. The probe was inserted in the center of the bore during measurement. from the strands with a Nb-chemical barrier (Table 2), as might be expected. Strand and coil J e val...

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“…These two methods each have their advantages and disadvantages [13]. The effect on thermal and electrical stabilization of adding a copper core to a superconducting multifilament wire is well documented [14], whereas this paper examines the possible added befits on mechanical properties, which may be obtained by adding such a copper core.…”

Section: Introductionmentioning

confidence: 99%

Effect on Deformation Process of Adding a Copper Core to Multifilament ${\rm MgB}_{2}$ Superconducting Wire

Hancock

Bay

2007

IEEE Trans. Appl. Supercond.

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Abstract-Using the PIT method, multifilament wire with different packing strategies has been manufactured. In all, three types of wire have been investigated, a 19-filament configuration using ex-situ powder in an Fe-matrix and two 8-filament configurations in an Fe-matrix applying a copper core, one using in-situ and another using ex-situ powder. The effect on the annealing requirements during mechanical processing of adding such a copper core has been investigated. The results show that the number of required annealings drops by about a factor of one half with the addition of a copper core. This finding is supported by numerical simulations of the deformation process which indicate that tensile stresses are concentrated around the middle of the wire during the drawing process. As such, strategic packing of the multifilament configuration can reduce the need for annealing during the mechanical deformation process. It is also found that the multifilament configuration using in-situ powder requires less annealing than the ex-situ counterpart. This is most likely due to the fact that in-situ powder is more readily compacted than ex-situ powder.Index Terms-Magnesium diboride, superconducting composites, superconducting filaments and wires, superconducting materials mechanical factors.

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Behavior of MgB2 React & Wind Coils Above 10 K

Cited by 35 publications

References 9 publications

Neutron Irradiation of SiC Doped and Magnesium Rich MgB$_{2}$ Wires

Neutron Irradiation of SiC Doped and Magnesium Rich MgB$_{2}$ Wires

Solenoidal coils made from monofilamentary and multifilamentary MgB₂strands

Effect on Deformation Process of Adding a Copper Core to Multifilament ${\rm MgB}_{2}$ Superconducting Wire

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Behavior of MgB2 React &amp; Wind Coils Above 10 K

Cited by 35 publications

References 9 publications

Neutron Irradiation of SiC Doped and Magnesium Rich MgB$_{2}$ Wires

Neutron Irradiation of SiC Doped and Magnesium Rich MgB$_{2}$ Wires

Solenoidal coils made from monofilamentary and multifilamentary MgB2strands

Effect on Deformation Process of Adding a Copper Core to Multifilament ${\rm MgB}_{2}$ Superconducting Wire

Contact Info

Product

Resources

About

Behavior of MgB2 React & Wind Coils Above 10 K

Solenoidal coils made from monofilamentary and multifilamentary MgB₂strands