摘要
晶界扩散重稀土元素是提高烧结钕铁硼磁体矫顽力的关键技术,但电流场辅助技术在该领域的应用相对较少。本研究选取商用N48M等级烧结钕铁硼磁体(剩磁Br=14.01 k Gs,内禀矫顽力Hcj=14.35 k Oe)为样品,通过物理气相沉积方法在磁体表面沉积金属Dy,磁体增重0.3 wt.%,并在910℃下进行真空热处理8 h以实现晶界扩散。在热处理期间,实验组沿垂直于镀Dy表面施加电流密度为20.8 A/cm^(2)的直流电流,对照组为无电流场的常规扩散。结果显示,实验组的剩磁和矫顽力分别为12.89 k Gs和18.39 k Oe,对照组分别为13.12 k Gs和17.82 k Oe。扫描电子显微镜(SEM)、能谱仪(EDS)的结果表明,相比于对照组,实验组的Dy原子明显扩散得更深且平均粒径更小,这是实验组矫顽力优于对照组的主要原因。研究结果表明,电流场辅助晶界扩散是一种提高烧结钕铁硼磁体矫顽力的可行技术方案,对于进一步优化钕铁硼磁体性能具有重要意义。
Grain boundary diffusion of heavy rare earth elements constitutes a pivotal technique for augmenting the coercivity in sintered neodymium-iron-boron magnets.Notwithstanding,the application of electric field-assisted technology in this realm remains relatively scant.The present study selects commercial-grade N48M sintered neodymium-iron-boron magnets(with a remanence Br=14.01 kGs and a coercivity Hcj=14.35 kOe)as the object of investigation,coating the magnet surface with a metallic dysprosium(Dy)film by the physical vapor deposition method,accounting for a 0.3%increment in the magnet’s weight,followed by a vacuum heat treatment at 910℃for 8 hours to facilitate grain boundary diffusion.During the heat treatment,the experimental group was applied a direct current with a current density of 20.8 A⋅cm^(-2) perpendicular to the Dy-coated surface,while the control group was subjected to conventional diffusion without the application of an electric field.The results show that the residual magnetism and coercivity of the experimental group were 12.89 kGs and 18.39 kOe,respectively,while those of the control group were 13.12 kGs and 17.82 kOe,respectively.The results of Scanning Electron Microscopy(SEM)and Energy Dispersive Spectrometer(EDS)indicate that,compared to the control group,the Dy atoms in the experimental group have diffused more deeply and have a smaller average particle size,which is the main reason for the superior coercivity of the experimental group.The research findings indicate that electric field-assisted grain boundary diffusion is a viable technological approach to enhancing the coercivity of sintered NdFeB magnets,which is of significant importance for further optimizing the performance of NdFeB magnets.
作者
房漠楠
刘海晨
吕军
吕燕武
黄二愿
FANG Monan;LIU Haichen;LYU Jun;LYU Yanwu;HUANG Eryuan(College of Sciences,Inner Mongolia University of Technology,Hohhot 010051,China;Baotou Pingao Permanent Magnetic Materials Co,Ltd,Baotou 014030,China;Inner Mongolia Key Laboratory of Thin Film and Coatings,Inner Mongolia University of Technology,Hohhot 010051,China;School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China)
出处
《内蒙古工业大学学报(自然科学版)》
2025年第4期377-384,共8页
Journal of Inner Mongolia University of Technology:Natural Science Edition
基金
内蒙古自治区自然科学基金项目(2022LHMS03014)
内蒙古自治区直属高校基本科研业务费项目(JY20220069,ZTY2023012)
“科技兴蒙”行动重点专项(XM2024XTGXQ02)。
关键词
烧结钕铁硼
晶界扩散
直流电场
矫顽力
sintered neodymium iron boron
grain boundary diffusion
direct current electric field
coercivity
