EAGER: Novel Nitride-Based Exchange-Spring Nanocomposites

新型氮化物基交换弹簧纳米磁性复合材料技术：随着电力需求的不断增长，人们越来越重视生产用于电机、发电机、执行器等的高功率密度电机。ESPM是磁性的吗？硬的？然后呢？柔软？交换耦合得到高能产物(BH)max的相。据报道，快速凝固、熔体旋压和球磨稀土过渡金属(RE-TM)金属间化合物的(BH)max值很高。此外，氮化物基ESPM有希望成为性能超过NdFeB-Fe RE-TM ESPM的永磁体。本研究探索了一种新型的低温合成技术，用于制备具有高(BH)max和工作温度的氮化物基纳米复合材料。这种合成技术是基于软相的硬磁相纳米粉末的层叠，硬相和软相的催化氮化，以及脉冲等离子体压实的低温致密化。这种方法应该提供更大的晶粒度控制和软硬相之间的交换耦合，更低温度的氮化物相合成，更低的温度压实，以及更好的耐腐蚀性。PI的目的是探索这些新型氮化物基纳米复合材料的合成，了解它们的性能，并优化它们的组成，以获得高能产品永磁体。这项工作的高回报来自于纳米复合材料中软铁相的低温催化氮化。如果成功，这项研究将产生两项重要突破，一是为氮化物基复合材料的合成开辟新的途径，二是为使用高能产品永磁体开发更节能、紧凑的设备提供具体指导。非技术性：该项目是一项很有前途的新技术，可用于生产功率密集型机械用的氮化物基交换耦合永磁体。这种方法从目前定义不明确的纳米级形态转移到空间和成分工程的纳米结构。这种新颖的设计方法通过利用材料的磁晶和形状各向异性，提供了以前无法获得的磁性。这项研究提供了工艺突破和基本理解，应有助于未来新型高性能永磁体的商业开发。这项研究工作与一项旨在向研究生和本科生教授研究方法的教育倡议相结合。

Novel Nitride-Based Exchange-Spring Magnetic NanocompositesTECHNICAL: With escalating power demands, there is an increased emphasis on producing high power density electrical machines for use as motors, generators, actuators, etc. A promising new technology to produce these power-dense machines employs exchange spring permanent magnets (ESPM). ESPMs are magnetically ?hard? and ?soft? phases that are exchange-coupled to give high energy products, (BH)max. High (BH)max values have been reported for rapidly-solidified, melt-spun, and ball-milled rare-earth-transition metal (RE-TM) intermetallic ESPMs. In addition nitride-based ESPMs are promising candidates for permanent magnets whose performance could exceed that of the NdFeB-Fe RE-TM ESPMs. In this research a novel low-temperature synthesis technique is examined for fabricating nitride-based nanocomposites with high (BH)max values and operating temperatures. This synthesis technique is based on laminating hard magnetic phase nanopowders with soft phases, catalytic nitrogenation of the hard and soft phases, and low temperature densification using pulse plasma compaction. This approach should provide greater grain size control and exchange-coupling between the hard and soft phases, lower temperature synthesis of the nitride phases, lower temperature compaction, and greater corrosion resistance. The PI intends to explore the synthesis of these novel nitride-based nanocomposites, to understand their properties and to optimize their compositions to obtain high energy product permanent magnets. The high payoff of this work derives from the low temperature catalytic nitrogenation of the soft iron phase in the nanocomposites. If successful, this study will yield two important breakthroughs, a new avenue for the synthesis of nitride-based composite materials and specific guidance for developing more energy efficient, compact devices using high energy product permanent magnets. NONTECHNICAL: This project is a promising new technology for the production of nitride-based exchange-coupled permanent magnets for power-dense machines. This approach moves away from current, poorly-defined, nanoscale morphologies to spatially and compositionally engineered nanostructures. This novel design approach offers previously unattainable magnetic properties by exploiting magnetocrystalline and shape anisotropy of materials. The research provides processing breakthroughs and fundamental understanding that should facilitate future commercial development of a new class of high performance permanent magnets. The research effort is coupled to an educational initiative aimed at teaching research methodology to graduate and undergraduate students.