SBIR Phase I: Optimization of a Sintering and Manufacturing Process for Prototype MgB2 Wires for Next-Generation Cryogenic-Free 1.5T and 3.0T MRI

这项小企业创新研究（SBIR）第一阶段项目将通过添加磁性和非磁性杂质，为下一代无低温1.5特斯拉(T)和3.0 T磁共振成像（MRI）系统开发原型MgB2导线。这些杂质会放大磁性杂质引起的涡流钉住，同时用非磁性杂质补偿伴随的磁性杂质引起的转变温度降低。这项新技术将显著增强II型超导体的高场特性（即增加临界电流密度和上临界场）。将普通超导体转化为磁性超导体，将为超导磁体技术开辟新的前沿。该SBIR项目对MgB2原型线的烧结和制造工艺进行了优化，以保证杂质沿线均匀分散，并以经济高效的方式实现最大临界电流密度。该项目将确定最佳烧结条件（即温度、压力和时间），利用液相烧结杂质，并将测试原位和非原位管内粉末（PIT）制造工艺，以在MgB2电线中生产最高临界电流密度。该项目的更广泛影响/商业潜力包括使用所得到的MgB2导线制造下一代无低温1.5T和3.0T核磁共振成像的可能性。低成本的下一代核磁共振成像仪将取代目前基于铌钛磁铁的核磁共振成像仪，极大地提高了公众的健康水平，因为这些核磁共振成像仪将在更高的温度（20 K）下工作，从而避免了对昂贵的液氦的需求。液氦制冷机的消除将导致简单而通用的设计和几乎免维护的操作，将MRI扫描成本降低高达40%。由此产生的MgB2线原型对于用于核磁共振（NMR）、粒子加速器和聚变反应堆的下一代无低温磁体也至关重要。此外，将该技术应用于Nb-Ti和Nb3Sn磁铁材料也很简单。因此，这种新技术有可能彻底改变超导磁体技术，开辟将普通超导体转化为磁性超导体的新研究领域。MgB2导线是电力传输、超导故障电流限制器、发电机和电动机等后续应用的可行候选者，所有这些都可以通过这项创新技术实现。

This Small Business Innovation Research (SBIR) Phase I project will develop prototype MgB2 wires for next generation cryogen-free 1.5 Tesla (T) and 3.0 T magnetic resonance imaging (MRI) systems, by adding both magnetic and nonmagnetic impurities. These impurities will amplify the vortex pinning due to magnetic impurities, while compensating the concomitant magnetic impurity-induced transition temperature reduction with nonmagnetic impurities. This new technique will lead to a significant enhancement of high field properties of type II superconductors (i.e. increased critical current densities and upper critical fields). This conversion of ordinary superconductors into magnetic superconductors will open a new frontier for superconducting magnet technology. This SBIR project employs optimization of a sintering and manufacturing process for prototype MgB2 wires to guarantee the homogeneous dispersion of impurities along the wire and to achieve the maximal critical current density in a cost efficient way. This project will determine the optimum sintering conditions (i.e., temperature, pressure, and time), utilizing liquid phase sintering of impurities, and will test both in-situ and ex-situ powder-in-tube (PIT) manufacturing processes for producing the highest critical current densities in MgB2 wires.The broader impact/commercial potential of this project includes the possibility of fabricating next-generation cryogen-free 1.5T and 3.0T MRIs, using the resulting MgB2 wires. The low-cost next-generation MRIs will replace the current Nb-Ti-magnet based MRIs, enhancing the public health significantly, because these envisioned MRIs will operate at a higher temperature, 20 K, obviating the need for expensive liquid helium. The elimination of liquid helium cryogen will lead to simple and versatile designs and almost maintenance-free operation, reducing the MRI scan cost up to 40%. The resulting prototype MgB2 wires will be also crucial for next generation of cryogen-free magnets for nuclear magnetic resonance (NMR), particle accelerators, and fusion reactors. Additionally, it is straightforward to apply this technique to Nb-Ti and Nb3Sn magnet materials. Accordingly, this novel technique has the potential to revolutionize superconducting magnet technology and opens a new research field of converting ordinary superconductors into magnetic superconductors. MgB2 wires are a viable candidate for follow-on applications in electric power transmission, superconducting fault current limiters, generators, and motors, all of which could be enabled by this innovative technique.