Study on reducing the charge delay of the no-insulation HTS coil after solder impregnation

Li, Y.Q.; Yin, Meiying; Zhang, J.W.; Li, Z.Y.; Hong, Zhiyong; Jin, Zhequan

doi:10.1016/j.physc.2018.06.004

Cited by 15 publications

(10 citation statements)

References 3 publications

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“…Such high SF can be obtained due to the application of rectangular MgB 2 wire with Al outer sheath self-insulated by anodic oxidation. Many non-insulated superconducting coils have been reported during the last ten years, and even coils impregnated by conductive solder have been proposed [21]. Compared with insulated coils, non-insulated ones have higher thermal stability, better self-protection and better quench recovery capability [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

“…Many non-insulated superconducting coils have been reported during the last ten years, and even coils impregnated by conductive solder have been proposed [21]. Compared with insulated coils, non-insulated ones have higher thermal stability, better self-protection and better quench recovery capability [21][22][23]. However, noninsulated coils have weaknesses such as magnetic field saturation and charge-discharge delay.…”

Section: Introductionmentioning

confidence: 99%

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Water ice-cooled MgB₂ coil made by wind and react process

Kòváč

Kopera

Melíšek

et al. 2022

Supercond. Sci. Technol.

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The wind and react (W&R) coil of inner diameter 53 mm has been made of multi-core MgB2/Nb/CuNi wire manufactured by internal magnesium diffusion (IMD) process. W&R coil is wound of not insulated rectangular wire of 1 mm2with only 5 µm thick stainless steel foil used for interlayer insulation. Transport current performance of the coil and short wire samples were measured in liquid He bath at external magnetic fields 4.5-8.5 T and also in self-field conditions inside the sub-cooled water ice at temperatures between 33 K and 38 K. The presented MgB2 coil exhibits stable behavior at water ice cooling and its high space factor allows to reach high current density of winding in comparison to the data of already published MgB2 coils. Presented results demonstrate that MgB2 windings can be used safely at He-free conditions inside the sub cooled water ice, and this technique can be further optimised and used for future MgB2 coils.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Water ice-cooled MgB₂ coil made by wind and react process

Kòváč

Kopera

Melíšek

et al. 2022

Supercond. Sci. Technol.

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“…The curing temperature and time of epoxy resin: Stycast 2850: 80 • C for 8-16 h [30]; Stycast 1266: 100 • C for 2 h [31]; The epoxy resin reported in [32]: 120 • C for 2 h; The epoxy resin reported in [33]: 150 • C. Solder impregnation of non-insulation HTS coils [34][35][36][37] 185 • C for half a minute [34]; 180 • C for about 1 h [37].…”

Section: <2 Hmentioning

confidence: 99%

“…The curing temperature of wax and epoxy resin is generally 30 • C-100 • C [28,29] and 80 • C-150 • C [30][31][32][33], respectively. Besides, the feasibility of the impregnation of HTS coils using solder was reported [34][35][36][37]. The solder impregnation was also applied in fabrication of cables, such as twisted stacked-tape cable (TSTC) [38], quasi-isotropic strand (Q-IS) cable [39], and vacuum pressure impregnated, insulated, partially transposed, extruded, and roll-formed (VIPER) cable [40,41], and the VIPER with solder impregnation played a significant role in MIT/CFS's 20 T SPARC toroidal field model coil [42,43].…”

Section: Introductionmentioning

confidence: 99%

Typical electrical, mechanical, electromechanical characteristics of copper-encapsulated REBCO tapes after processing in temperature under 250 °C

Pan

Yu³

et al. 2023

Supercond. Sci. Technol.

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Heat treatments are inevitable not only in the production of rare earth barium copper oxide (REBCO) tapes, but also in their post-processing for applications, typically, in soldering and epoxy/wax impregnation during the fabrication of REBCO coils. In general, the heat treatment of REBCO tapes should be carried out at lower temperature for a shorter time, but the specific safe boundary of heat-treatment temperature and time for REBCO tapes is still unknown. Therefore, a comprehensive study on the typical electrical, mechanical, and electromechanical characteristics of REBCO tapes after heat treatments under temperature of 250 ℃ is necessary. This work focus on the copper-encapsulated REBCO tapes, which are more robust (while with much lower engineering current density) to be processed in application systems than the tapes without encapsulation. The critical current degradation, stress-strain characteristic, and electromechanical properties of REBCO tapes were measured after heat treatments at different temperatures in argon and oxygen atmosphere. A 2D finite element analysis model was established for detailed stress/train analyzes under tension and bending based on the analysis of residual stress/strain. The results indicate that the critical current of the copper-encapsulated REBCO tapes decreases with increasing heat-treatment temperature and dwell time, and is of no evident relation to atmosphere. In addition, increased temperature of heat treatment leads to an obvious decrease in the yield strength and critical tensile stress. This effect is mainly attributed to the degradation of mechanical properties of the encapsulated copper layer, which is demonstrated by the combination of our finite element simulation and the experiments results. Interestingly, the change in the critical bending radius due to heat treatments was slight, because the bending axial strain of the REBCO layer remained almost unchanged after heating. It is also worthy to note that all the properties tested in this study were irrelevant to the external oxygen partial pressure during the heating process. As a practical conclusion for the application systems, an upper and atmosphere-irrelevant limit of processing temperature of 130 or 150 ℃ (2 h dwell time) was proposed for copper-encapsulated REBCO tapes, under which the critical current, yield strength, critical tensile stress/strain and critical bending radius of the copper-encapsulated REBCO tapes decay by < 1% or 3%, respectively.

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“…However, their mechanical properties are weak and may not contribute too much to the overall mechanical stability of the large high-field magnets [25]. Recent experiments showed that the mechanical stability of no-insulation (NI) HTS coils can be greatly enhanced using the solder impregnation method [26,27]. But the time constant of the solder impregnated coil is large.…”

Section: Introductionmentioning

confidence: 99%

Performance study of a new epoxy resin IR-3 in HTS-based high-field magnet application

Yao¹,

Zhang²,

Wang³

et al. 2022

Mater. Res. Express

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REBCO (Rare-earth-based barium copper oxide) conductors are appropriate materials for high-field magnet applications. Vacuum impregnation using epoxy resin is a technique widely used for stable operation of superconducting coils. However, epoxy-impregnated REBCO coils often experience critical current degradation problems. Finding a suitable impregnating material for REBCO coils is important for their application in high-field superconducting magnets. A new toughness epoxy, IR-3, was developed recently. An in-depth understanding of IR-3 on the performance of REBCO coils is critically necessary for its application. Thus, this paper explores the effects of IR-3 impregnation on the performance of REBCO coils at 77 K and 4.2 K. The test results are compared to similar coils impregnated with CTD-101 K and MY750. Meanwhile, the radial stresses at 77 K in self-field and 4.2 K under 10 T were simulated. All epoxy impregnated REBCO coils showed no decay in critical current after thermal cycles at 77 K. When charged at 4.2 K in external fields of 5 T and 10 T, the IR-3 impregnated REBCO coils avoided performance degradation problems and had superior electrical stabilities. Combing the excellent performance at low temperatures, IR-3 is a promising candidate material for impregnating high-field REBCO coils.

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Study on reducing the charge delay of the no-insulation HTS coil after solder impregnation

Cited by 15 publications

References 3 publications

Water ice-cooled MgB₂ coil made by wind and react process

Water ice-cooled MgB₂ coil made by wind and react process

Typical electrical, mechanical, electromechanical characteristics of copper-encapsulated REBCO tapes after processing in temperature under 250 °C

Performance study of a new epoxy resin IR-3 in HTS-based high-field magnet application

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Study on reducing the charge delay of the no-insulation HTS coil after solder impregnation

Cited by 15 publications

References 3 publications

Water ice-cooled MgB2 coil made by wind and react process

Water ice-cooled MgB2 coil made by wind and react process

Typical electrical, mechanical, electromechanical characteristics of copper-encapsulated REBCO tapes after processing in temperature under 250 °C

Performance study of a new epoxy resin IR-3 in HTS-based high-field magnet application

Contact Info

Product

Resources

About

Water ice-cooled MgB₂ coil made by wind and react process

Water ice-cooled MgB₂ coil made by wind and react process