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

这个小型企业创新研究(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1.5Tesla(T)和3.0T磁共振成像(MRI)系统开发原型MgB2导线。这些杂质将放大由于磁性杂质引起的涡旋钉扎，同时用非磁性杂质补偿伴随的磁性杂质引起的相变温度降低。这项新技术将显著提高II型超导体的强场性质(即增加临界电流密度和上临界场)。将普通超导体转变为磁性超导体，将为超导磁体技术开辟一个新的前沿。该SBIR项目对原型镁B2线材的烧结和制造工艺进行了优化，以确保杂质沿线材的均匀分散，并以经济高效的方式实现最大的临界电流密度。该项目将确定最佳烧结条件(即温度、压力和时间)，利用杂质的液相烧结，并将测试原位和异地管内粉末(PIT)制造工艺，以生产最高临界电流密度的镁B2线材。该项目的更广泛影响/商业潜力包括使用最终得到的镁B2线材制造下一代无冷媒1.5T和3.0T磁共振成像的可能性。低成本的下一代磁共振成像将取代目前基于Nb-Ti磁体的磁共振成像，显著提高公众健康，因为这些设想的磁共振成像将在更高的温度下运行，即20K，消除了对昂贵的液氦的需求。液氦制冷剂的取消将导致设计简单和通用，几乎无需维护操作，使MRI扫描成本降低高达40%。由此产生的原型镁B2线材也将对用于核磁共振、粒子加速器和聚变反应堆的下一代无冷源磁体至关重要。此外，将该技术应用于Nb-Ti和Nb_3Sn磁体材料也是非常简单的。因此，这一新技术有可能给超导磁体技术带来革命性的变化，并开辟了将普通超导体转变为磁性超导体的新研究领域。在电力传输、超导故障限流器、发电机和电机的后续应用中，MgB2线材是一个可行的候选方案，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.