Composite bulk superconducting magnets for high field applications

RE- ba - cu - o（其中RE=稀土元素，如Y， Nd, Sm， Gd等）块状熔体加工高温超导体[(RE)BCO]家族是世界范围内广泛研究的主题，主要是因为它们具有捕获大磁场的潜力。剑桥大块超导小组已经证明了这一点，他们最近用这些材料创造了一个新的世界纪录，在26 K下，捕获场为17.6 T，打破了保持了10多年的世界纪录。在过去的20年里，剑桥集团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。块体（RE）BCO超导体在其研究和发展中已经达到了重要和关键的阶段。它们惊人的磁场产生特性在一系列可持续的工程应用中具有很高的潜力，包括飞轮储能、电机和发电机、磁分离器、生物医学应用和磁悬浮装置。这一提议是为了将基础材料研究和实际组件的发展结合起来，以产生实际的磁场，使用大块超导体，这是第一次在工程设备中常规和商业使用。该项目的主要目标是在低温（50 K和30 K）下形成磁场，在低温下，临界电流和磁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的机械强度和导热性的材料，以获得高场中通过脉冲磁化的样品和组件的最佳性能。快速发展的低温冷却器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。单粒（RE）BCO块状超导体的机械强度和导热性得到了改善，将被纳入不同（RE）BCO材料的不同复合形状的组件中，以实现对磁场强度和分布的控制。这些组件的特性和性能将与77k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较低。在我们目前EPSRC对多种子的资助下开发的能力将进一步使多种子、准单颗粒的制造成为可能，其性能将与类似大小的更小、紧密排列的样品的组装进行比较。将在77 K下测量不同排列顺序的不同（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晶粒的性质进行比较。该项目将继续支持在英国学校、学院和大学的推广，受益于包括波音公司、西门子和Bio-med（英国）在内的主要国际工业合作伙伴的强大财政支持。

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).