To explore the potential of iron-based superconducting (IBS) tapes in high-field applications, IBS pancake coils were dry-wound using the uninsulated IBS tape, supplemented with cowound stainless steel tapes for reinforcement. We have successfully fabricated a double pancake coil (DP-1) and a series-connected coil consisting of six DP coils (DP-6). These coils underwent multiple charging tests in a 35 T resistive magnet and retesting in a 14 T superconducting magnet. After conducting multiple rounds of retesting in two different background field magnets, it was found that the IBS coils did not show any degradation in their current-carrying performance. The critical current (I _c) value of the DP-1 at 4.2 K and 32 T reached 60 A. To systematically evaluate the I _c performance of the six coils in the DP-6, we monitored the V–I curves between 26 voltage taps. The resistive voltage rise was observed at low charging currents, indicating that each coil has suffered different levels of damage. Nevertheless, the overcurrent tests demonstrated that the IBS coil can still carry a current far exceeding its I _c without irreversible degradation. We concluded the possible reasons for these phenomena by analyzing the experimental details and test data. In addition, the coil’s internal structure was observed to assess the quality of coil winding, joint soldering, and epoxy resin impregnation. This study will provide references for the electromagnetic and mechanical properties of IBS tapes under ultra-high magnetic fields and contribute to the future development of higher-performance practical IBS coils.

中文翻译：

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金属绝缘铁基超导线圈的开发及高达32T高磁场下的充电测试


为了探索铁基超导 (IBS) 胶带在高场应用中的潜力，使用非绝缘 IBS 胶带对 IBS 薄饼线圈进行干绕，并辅以牛皮不锈钢胶带进行加固。我们已经成功制造了双扁平线圈（DP-1）和由六个DP线圈组成的串联线圈（DP-6）。这些线圈在 35 T 电阻磁体中进行了多次充电测试，并在 14 T 超导磁体中进行了重新测试。在两种不同背景磁场的磁体中进行多轮重新测试后，发现IBS线圈的载流性能没有出现任何下降。 DP-1在4.2 K和32 T下的临界电流（ _c ）值达到60 A。为了系统地评估DP-6中六个线圈的 _c 性能，我们监测了 26 个电压抽头之间的 V-I 曲线。在低充电电流下观察到电阻电压升高，表明每个线圈都遭受了不同程度的损坏。尽管如此，过流测试表明IBS线圈仍然可以承载远远超过其 _c 的电流，而不会出现不可逆的退化。我们通过分析实验细节和测试数据总结出这些现象的可能原因。此外，还观察线圈的内部结构，以评估线圈绕制、接头焊接和环氧树脂浸渍的质量。该研究将为超高磁场下IBS带的电磁和机械性能提供参考，并为未来开发更高性能的实用IBS线圈做出贡献。