Liu Zhuang, Zhang Chaoyue, Wu Haichen, Chen Renjie, Yan Aru
CISRI & NIMTE Joint Innovation Center for Rare Earth Permanent Magnets, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Materials (Basel). 2022 Jul 25;15(15):5160. doi: 10.3390/ma15155160.
In this study, the effects of YO addition on the magnetic properties, microstructure and magnetization reversal behavior of Sm(CoFeCuZr) magnet were investigated. By addition of YO, the coercivity was increased from 21.34 kOe to 27.42 kOe at 300 K and from 5.14 kOe to 6.27 kOe at 823 K. A magnet with a maximum magnetic energy product of 9.86 MGOe at 823 K was obtained. With the interdiffusion of Y and Sm after appropriate addition, the Cu content within the cell boundary phase close to the oxide was detected to be nearly twice as high as that away from the oxide. We report for the first time that a collection of lamellar phases were formed on both sides of the inserted oxide, providing a strong pinning field against magnetic domain wall motion based on in-situ Lorentz TEM observation. Furthermore, the ordering process of the original magnet was delayed after YO addition, resulting in the refinement of cellular structure, which can also enhance the domain wall pinning ability of cellular structures based on micromagnetic simulation. However, excessive addition of YO led to large Cu-rich phase and Zr-rich impurity phase precipitated at the edge of the oxide, resulting in the destruction of cellular structures and a significant reduction in coercivity. This study provides a new technical approach to regulate the microstructure of SmCo type magnets. Addition of YO is expected to play a significant role in improvement of high temperature magnetic properties.
在本研究中，研究了添加YO对Sm(CoFeCuZr)磁体的磁性能、微观结构和磁化反转行为的影响。通过添加YO，在300 K时矫顽力从21.34 kOe增加到27.42 kOe，在823 K时从5.14 kOe增加到6.27 kOe。获得了在823 K时最大磁能积为9.86 MGOe的磁体。经过适当添加后，随着Y与Sm的相互扩散，检测到靠近氧化物的胞界相内的Cu含量几乎是远离氧化物处的两倍。基于原位洛伦兹透射电子显微镜观察，我们首次报道在插入的氧化物两侧形成了层状相的集合，为磁畴壁运动提供了强大的钉扎场。此外，添加YO后原始磁体的有序化过程延迟，导致胞状结构细化，基于微磁模拟，这也可以增强胞状结构的畴壁钉扎能力。然而，过量添加YO会导致在氧化物边缘析出大量富Cu相和富Zr杂质相，导致胞状结构破坏和矫顽力显著降低。本研究提供了一种调节SmCo型磁体微观结构的新技术方法。添加YO有望在改善高温磁性能方面发挥重要作用。
