Trinh T Thuy, Kim Jungryang, Sato Ryota, Matsumoto Kenshi, Teranishi Toshiharu
Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan.
Sci Technol Adv Mater. 2021 Jan 22;22(1):37-54. doi: 10.1080/14686996.2020.1862630.
Multielement rare earth (R)-transition metal (T) intermetallics are arguably the next generation of high-performance permanent magnetic materials for future applications in energy-saving and renewable energy technologies. Pseudobinary SmFeN and (R,Zr)(Fe,Co,Ti) (R = Nd, Sm) compounds have the highest potential to meet current demands for rare-earth-element-lean permanent magnets (PMs) with ultra-large energy product and operating temperatures up to 200°C. However, the synthesis of these materials, especially in the mesoscopic scale for maximizing the maximum energy product ( ), remains a great challenge. Nonequilibrium processes are apparently used to overcome the phase-stabilization challenge in preparing the R-T intermetallics but have limited control of the material's microstructure. More radical bottom-up nanoparticle approaches based on chemical synthesis have also been explored, owing to their potential to achieve the desired composition, structure, size, and shape. While a great achievement has been made for the SmFeN, progress in the synthesis of (R,Zr)(Fe,Co,Ti) magnetic mesoscopic particles (MMPs) and R-T/T exchange-coupled nanocomposites (NCMs) with substantial coercivity ( ) and remanence ( , respectively, remains marginal.
多元素稀土（R）-过渡金属（T）金属间化合物可以说是下一代高性能永磁材料，有望应用于未来的节能和可再生能源技术。伪二元SmFeN和（R,Zr）（Fe,Co,Ti）（R = Nd, Sm）化合物最有潜力满足当前对具有超大能量积和高达200°C工作温度的低稀土元素永磁体（PMs）的需求。然而，这些材料的合成，尤其是在介观尺度上以最大化最大能量积（ ），仍然是一个巨大的挑战。非平衡过程显然被用于克服制备R-T金属间化合物时的相稳定挑战，但对材料微观结构的控制有限。由于基于化学合成的更激进的自下而上纳米颗粒方法有潜力实现所需的成分、结构、尺寸和形状，因此也已被探索。虽然在SmFeN方面已取得巨大成就，但在合成具有高矫顽力（ ）和剩磁（ ）的（R,Zr）（Fe,Co,Ti）磁性介观颗粒（MMPs）和R-T/T交换耦合纳米复合材料（NCMs）方面的进展仍然有限。
