SBIR Phase II: Fe-nanoparticle Coating of Anisotropic Magnet Powder for Nanocomposite Permanent Magnets with Enhanced (BH)max

这个小企业创新研究第二阶段项目提出了一种创新和简便的方法来合成复合磁铁粉末涂有铁和/或Fe-Co纳米粒子，并将它们巩固成高性能的各向异性纳米复合磁铁的发展。在20世纪90年代，理论上预测，由具有高磁晶各向异性的硬磁相和具有高饱和磁化强度的软磁相组成的两相交换耦合纳米复合磁体可以表现出最大能量积（BH）max是当前磁体的值的两倍。在本研究中，我们将以化学与物理相结合的方法，将铁及铁钴奈米粒子沉积在硬磁性粉末上。与以前采用的技术不同，所提出的方法允许控制软磁相的尺寸到纳米级。此外，该方法与大规模生产兼容。随后通过压力和温度辅助方法固结这些复合粉末将导致新一代高性能各向异性纳米复合永磁体，其（BH）max远高于当前商业磁体。核心粉末的多种选择将导致新的改进磁体接近室温的应用（Nd 2Fe 14 B基），高温应用（SmCo 5和Sm 2Fe 17 Nx基）和超高温应用（Sm 2Co 17基）。成功开发新型（纳米）复合磁体将直接导致电磁器件功能的改进，并最终导致当前永磁体不可能实现的新应用。磁铁。更高性能的磁体将导致更轻的重量，更小的占地面积，并降低商业和军事应用中电磁设备的总系统成本。最知名的应用是：混合动力汽车（永磁电机和发电机、传感器和执行器）、航天器（动量轮、反作用轮、步进电机、离子推进）、微波源（行波管放大器、速调管、磁控管）、微波元件（隔离器、循环器）、惯性制导（加速度计、陀螺仪）和其他商业系统（计算机磁盘驱动器、计算机打印机、音频系统、卫星通信、医学成像、步进电机等）。该提案是一项涉及物理、化学和冶金学的多学科事业。自下而上的方法来合成的纳米复合材料磁体与均匀和可控的厚度的软磁壳形成的前体纳米颗粒涂层，将允许详细的实验表征的磁相互作用。这将提供有价值的信息，以了解和大大减少理论预测和工程能力之间的差距差距。

This Small Business Innovation Research Phase II project proposes the development of an innovative and facile method to synthesize composite magnet powders coated with Fe and/or Fe-Co nanoparticles and to consolidate them into high performance anisotropic nanocomposite magnets. It was theoretically predicted in the 1990s that two phase exchange-coupled nanocomposite magnets consisting of a hard magnetic phase with high magnetocrystalline anisotropy and a soft magnetic phase with high saturation magnetization may exhibit a maximum energy product (BH)max twice the value of the current magnets. In this research effort, Fe and Fe-Co nanoparticles will be deposited onto hard magnetic powders by combined chemical and physical methods. Unlike previously employed techniques, the proposed approach allows the control of the size of soft magnetic phase to the nanoscale. Moreover, the approach is compatible with mass production. Subsequent consolidation of these composite powders by pressure and temperature assisted methods will lead to a new generation of high performance anisotropic nanocomposite permanent magnets with a (BH)max much higher than that of the current commercial magnets. The multiple choices for the core powder will result in new improved magnets for close-to-room-temperature applications (Nd2Fe14B-based), high temperature applications (SmCo5- and Sm2Fe17Nx-based) and ultra-high temperature applications (Sm2Co17-based).The success in the development of the new (nano)composite magnets will directly result in the improvement of the functionality of electromagnetic devices and eventually lead to new applications not possible with the current permanent magnets. The higher performance magnets will result in even lighter weight, smaller footprint and lower the total system cost for electromagnetic devices in both commercial and military applications. The most well known applications are in: hybrid cars (permanent magnet motors and generators, sensors and actuators), spacecraft (momentum wheels, reaction wheels, stepper motors, ion propulsion), microwave sources (traveling wave tube amplifiers, klystrons, magnetrons), microwave components (isolators, circulators), inertial guidance (accelerometers, gyros), and other commercial systems (computer disk drives, computer printers, audio systems, satellite communication, medical imaging, stepper motors, etc). The proposal is a multidisciplinary enterprise involving physics, chemistry, and metallurgy. The bottom-up approach to the synthesis of nanocomposite magnets with uniform and controllable thickness of the soft magnetic shell formed from the precursor nanoparticle coating, will allow for an in-detail experimental characterization of magnetic interactions. This will provide valuable information to understand and substantially diminish the gap between the theoretical predictions and engineering capabilities.