( 1. 中南大学 粉末冶金国家重点实验室, 长沙 410083;
2. 北京科技大学 材料科学与工程学院, 北京 100083)
摘 要: 利用新研制的磁场注射成形机，研究了磁粉表面改性处理、 取向磁场强度及装载量对注射成形各向异性粘结NdFeB磁体性能的影响。结果表明： 磁粉经硅烷改性后， 可在其表面形成一层抗氧化膜， 其氧化质量增加率由2.3%下降至0.35%，相应制得的粘结磁体最大磁能积及抗压强度分别提高了17.8%和35.9%； 而随着取向磁场强度的增加， 磁体剩磁Br及矫顽力bHc均有较大幅度的增加， 但其内禀矫顽力iHc则基本不变； 同时， 通过实验得出了最佳的装载量为65%(体积分数), 并制备了最大磁能积（BH）max及抗压强度σbb分别为99 kJ/m3和125 MPa的注射成形粘结NdFeB磁体。
关键字: 注射成形； 粘结钕铁硼磁体； 表面改性； 取向磁场
（ 1. State Key Laboratory for Powder Metallurgy，
Central South University， Changsha 410083, China;
2. School of Materials Science and Engineering，
University of Science and Technology Beijing， Beijing 100083, China）
Abstract: The effects of surface modification of NdFeB powder， alignment magnetic field and powder volume fraction on the properties of injection molding anisotropic bonded NdFeB magnet were investigated with the magnetic injection molding machine designed by ourselves. The results show that the mass gain rate of magnetic powder treated with the silane decreases from 2.3% to 0.35% due to the formation of the anti-oxidation film on the powder surface， and the maximum energy product (BH)max and the compressive strength σbb of the corresponding bonded magnet are improved by 17.8% and 35.9%. With alignment magnetic field increasing， the remanence Br and coercivity bHc of bonded magnet tend to increase significantly while the coercivity iHc is almost unchanged. At the same time,the optimal powder volume fraction 65% is obtained and injection molding anisotropic bonded NdFeB magnet, whose(BH)max and σbb are 99 kJ/m3 and 125 MPa respectively, is made.
Key words: injection molding; bonded NdFeB magnet; surface modification; alignment magnetic field
