亚微米或纳米级稀土永磁材料的制备、结构及磁性能

Preparation, Structure and Magnetic Properties of Submicron or Nanometer Rare Earth Permanent Magnet Materials

摘要: 稀土过渡金属(RE-TM)亚微米和纳米粒子可作为高级块体磁体和高密度磁记录介质的基石。采用表面活性剂辅助低温磨(SACM)制备了Nd2Fe14B、Sm2Fe17Nx和SmCo5纳米薄片。2-甲基戊烷因其熔点极低而被选为溶剂。采用场发射扫描电子显微镜，激光粒度仪，振动样品磁强计等分析测试手段系统地研究了球磨温度对球磨后纳米薄片的形貌、粒度、显微组织和磁性能的影响。与表面活性剂辅助球磨法制备的纳米薄片相比，SACM法制备的永磁材料的形貌、尺寸、结构和磁性能有着显著的影响。低温球磨比常温球磨可以获得更小、更均匀、低氧和磁性能高的永磁纳米材料，这对于细化稀土永磁颗粒、制备高性能粘接和烧结磁体和纳米复合永磁材料有着重要的意义。

Abstract: Rare earth-transition metal (RE-TM) submicro- and nano-particles could be used as building blocks for advanced bulk magnets and high-density magnetic recording media. An innovative technology, surfactant-assisted cryomilling (SACM), was developed to prepare the Nd2Fe14B, Sm2Fe17Nx, and SmCo5 nanoflakes. 2-methyl pentane was selected as a solvent due to its extremely low melting point. The effects of ball-milling temperature on the morphology, particle size, microstructure, and magnetic properties of the nano-flakes were systematically investigated using field-emission scanning electron microscopy, laser particle size analysis, vibrating sample magnetometry, and other analysis methods. Compared with the nano-flakes prepared using surface-active agent-assisted ball milling, the morphology, size, structure, and magnetic properties of the permanent magnet materials prepared using SACM were significantly different. Cryogenic ball milling was found to produce smaller, more uniform, low-oxygen, and higher magnetic performance nanomaterials than room temperature ball milling. This has important implications for refining rare earth permanent magnet particles, preparing high-performance bonded and sintered magnets, and nanocomposite permanent magnet materials.