Composite bulk superconducting magnets for high field applications

RE-Ba-Cu-O（其中RE =稀土元素，例如Y、Nd、Sm、Gd等）一系列大块的、熔融加工的高温超导体[（RE）BCO]是世界范围内广泛研究的主题，主要是由于它们捕获大磁场的潜力。这已经被剑桥体超导小组（Bulk Superconductivity Group）详细地证明了，该小组最近使用这些材料在26 K下创造了17.6 T的新的世界纪录，打破了之前保持了10多年的世界纪录。剑桥集团在过去的20年里一直处于该领域研究的前沿，除了EPSRC和其他政府来源的资助外，还吸引了大量持续的行业资助。体相（RE）BCO超导体的研究和发展已进入一个重要而关键的阶段。其壮观的发电特性在一系列可持续工程应用中具有很高的潜力，包括飞轮储能、电动机和发电机、磁选机、生物医学应用和磁悬浮装置。该提案旨在将基础材料研究和实际组件的开发进行独特而及时的结合，以使用可以首次在工程设备中常规和商业使用的大块超导体产生实际磁场。该项目的主要目标是在低温（50 K和30 K）下形成磁场，其中临界电流和场产生能力明显高于77 K。将开发用于提高样品和组件结构中的机械强度和热导率的材料，以使通过脉冲磁化专门磁化的样品和组件在高场中获得最佳性能。快速发展的低温制冷机技术越来越有可能在低于77 K的温度下实现实际应用，这将推动改进材料和新结构的发展。开发的具有改进的机械强度和热导率的单颗粒（RE）BCO块状超导体将被并入不同（RE）BCO材料的不同复合形状的组件中，以能够控制磁场强度和分布。将这些组件的性质和性能与77 K下具有可比表面积的较大尺寸的单个样品进行比较，其中对机械强度的要求相对适中。在我们目前的EPSRC多晶种资助期间开发的能力将进一步实现多晶种、准单晶粒的制造，其性能将与类似尺寸的较小、紧密堆积的样品组装进行比较。将在77 K下测量以不同顺序排列的不同（RE）BCO超导体组件的捕获场和悬浮力，并与相同尺寸的常规单颗粒的特性进行比较。该项目将继续支持英国学校，学院和大学的推广，受益于主要国际工业合作者的强大财政支持，包括波音公司，Siemens和Bio-med（英国）。

The RE-Ba-Cu-O (where RE= rare earth element such as Y, Nd, Sm, Gd, etc.) family of bulk, melt processed high temperature superconductors [(RE)BCO] is the subject of extensive world-wide research due primarily to their potential to trap large magnetic fields. This has been demonstrated spectacularly by the Cambridge Bulk Superconductivity Group, which recently set a new world record trapped field of 17.6 T at 26 K using these materials, breaking the previous world record that had stood for more than 10 years. The Cambridge Group has been at the forefront of research in this area for the past 20 years and, in addition to funding from EPSRC and other government sources, has attracted substantial and sustained industry funding. Bulk (RE)BCO superconductors have reached an important and critical stage in their research and development. Their spectacular field generating properties have high potential for a range of sustainable engineering applications, including flywheel energy storage, motors and generators, magnetic separators, bio-medical applications and magnetic levitation devices. This proposal is for a unique and timely combination of fundamental materials research and the development of practical assemblies to generate practical magnetic fields using bulk superconductors that can be used routinely and commercially in engineering devices for the first time. The main objective of the project will be to shape the magnetic field at low temperatures (50 K and 30 K), where critical current, and hence field generating capability, is significantly higher than at 77 K. Materials to improve the mechanical strength and the thermal conductivity for incorporation in the sample and assembly structures will be developed to obtain optimum performance in high field for samples and assemblies magnetised specifically by pulse magnetisation. It is becoming increasingly likely that rapidly developing cryo-cooler technology will enable practical applications at temperatures below 77 K, and this will drive the development of improved materials and new structures. The single grain, (RE)BCO bulk superconductors developed with improved mechanical strength and thermal conductivity will be incorporated into assemblies of different composite shapes of different (RE)BCO materials to enable the control of magnetic field strength and distribution. The properties and performance of these assemblies will be compared with larger sized, individual samples of comparable surface areas at 77 K where the requirement for mechanical strength is relatively modest. Capability developed during our current EPSRC grant on multi-seeding will further enable the fabrication of multi-seeded, quasi-single grains, whose properties will be compared with an assembly of smaller, closely packed samples of similar sizes. The trapped field and levitation force of assemblies of different (RE)BCO superconductors arranged in different orders will be measured at 77 K and compared with the properties of conventional, single grains of the same size.The project, which will continue to support outreach in UK school, colleges and universities, benefits from strong financial support of major international industrial collaborators, including the Boeing Company, Siemens and Bio-med (UK).