Ultra low resistance joints for high temperature superconducting magnets

用于高温超导磁体的超低电阻接头

• 批准号: 2747163
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2747163
• 关键词: Ultra; low; resistance; joints; temperature

The next generation of ultra-high field magnets for applications in healthcare and materials characterisation will need us to take advantage of the exceptional properties of high temperature superconducting (HTS) materials. One of the most challenging design features in these magnets is the requirement for joints between individual lengths of superconducting wire that allow the passage of persistent currents (resistances less than 10-14 Ohms!) in very high magnetic fields. This EPSRC Industrial CASE project with Oxford Instruments will focus on designing novel processes to form joints between commercial high temperature superconductors, and measuring their performance under real engineering conditions. It will build Oxford Instruments' world leading expertise in high field superconducting magnets and the successful long standing collaboration with the Department of Materials at the University of Oxford. Practical high field superconducting magnet systems with high temporal persistence will require low resistance joints between high temperature superconductors (HTS). Further to this, joints between HTS and low temperature superconductor (LTS) materials will have practical applications in HTS/LTS hybrid superconducting magnets. Several the developed jointing techniques will be selected based on their suitability and applied to the manufacture of demonstration superconducting magnet coils incorporating such a joint. Tests will then be carried out to demonstrate the applicability of the techniques to real research instruments. Work to date at Oxford Materials has resulted in a method of making superconducting joints that have limited current capacity. A novel research challenge for this studentship is the development of joints with comparable critical current to the superconducting wire itself.In addition to providing experimental data to clarify the practicalities of self-jointing at low resistance between candidate HTS materials such as Bi2Sr2CaCu2O8 (Bi-2212) and REBa2Cu3O7 (REBCO), the project will further encompass work to determine the practical possibilities of joining ceramic HTS materials to candidate low temperature superconducting metal alloys (LTS) which presents a further materials challenge and has practical applications in HTS/LTS hybrid superconducting magnets. Integration of superconducting joints into a practical magnet coil represents a further challenge due to the need for repeatability and robustness of the joint. A practical engineering solution must survive repeated thermal cycles and high magnetic fields that would be present in high field superconducting magnet systems. The student will begin by developing existing powder in tube jointing techniques applied to Bi-2212 multifilamentary wires, developed by Oxford Materials. The work will involve experiments to provide clarity on the practicalities of self-jointing at low resistance between HTS materials such as Bi-2212 and REBCO, and between HTS and candidate LTS materials. Measurement of the transport properties of the joints will be carried out as an assessment of joint quality, and techniques such as SEM will be used to explore the microstructure of joints. The work will culminate in manufacture of technology demonstration coils incorporating the preferred method of superconducting joint. These will be designed, built, and tested at cryogenic temperature at Oxford Instruments site at Tubney Woods in Oxfordshire, with support from OI personnel. Training on product focussed research within the technology development team would perfectly complement the academic focus in the materials group at Oxford University. This materials technology is key for future products both for the study of quantum phenomena and to enhance capabilities in NMR for solids and liquids, especially those required for long chain molecule characterisation at high temporal persistence.

用于医疗保健和材料表征应用的下一代超高场磁体将需要我们利用高温超导 (HTS) 材料的卓越性能。这些磁体中最具挑战性的设计特征之一是要求各个长度的超导线之间存在接头，以允许在非常高的磁场中持续电流通过（电阻小于 10-14 欧姆！）。与牛津仪器公司合作的这个 EPSRC 工业案例项目将专注于设计在商业高温超导体之间形成接头的新颖工艺，并测量其在实际工程条件下的性能。它将建立牛津仪器在高场超导磁体方面世界领先的专业知识以及与牛津大学材料系的成功长期合作。具有高时间持久性的实用高场超导磁体系统将需要高温超导体（HTS）之间的低电阻接头。除此之外，高温超导和低温超导（LTS）材料之间的接合将在高温超导/低温超导混合超导磁体中具有实际应用。几种已开发的连接技术将根据其适用性进行选择，并应用于制造包含此类接头的示范超导磁体线圈。然后将进行测试，以证明这些技术对实际研究仪器的适用性。迄今为止，牛津材料公司的工作已经找到了一种制造电流容量有限的超导接头的方法。该学生的一项新的研究挑战是开发具有与超导线本身相当的临界电流的接头。除了提供实验数据来阐明候选高温超导材料（例如 Bi2Sr2CaCu2O8 (Bi-2212) 之间低电阻自接合的实用性） ）和 REBa2Cu3O7 (REBCO)，该项目将进一步包括确定将陶瓷 HTS 材料连接到候选低温超导金属合金 (LTS) 的实际可能性，该合金提供了进一步的材料挑战并在高温超导/低温超导混合超导磁体中具有实际应用。由于需要接头的可重复性和坚固性，将超导接头集成到实际的磁体线圈中提出了进一步的挑战。实用的工程解决方案必须能够承受高场超导磁体系统中存在的重复热循环和高磁场。学生将首先开发现有的粉末管连接技术，应用于牛津材料公司开发的 Bi-2212 多丝线。这项工作将涉及实验，以明确 Bi-2212 和 REBCO 等 HTS 材料之间以及 HTS 和候选 LTS 材料之间低电阻自接合的实用性。接头传输特性的测量将作为接头质量的评估，并且将使用 SEM 等技术来探索接头的微观结构。这项工作最终将采用超导接头的首选方法制造技术演示线圈。这些设备将在 OI 人员的支持下，在位于牛津郡塔布尼伍兹的牛津仪器工厂进行低温设计、制造和测试。技术开发团队内以产品为中心的研究培训将完美补充牛津大学材料小组的学术重点。这种材料技术是未来产品的关键，既可用于研究量子现象，又可增强固体和液体的核磁共振能力，尤其是高时间持久性下长链分子表征所需的能力。