注射成形法制取各向异性粘结NdFeB磁体的研究

Research in Anisotropic Bonded NdFeB Magnet from Injection Molding

研究了磁粉粒度、取向磁场强度、取向时间及装载量对注射成形各向异性粘结NdFeB磁体性能的影响,并分析了其原因。结果表明:NdFeB磁粉粒径太粗或太细均不利于磁体性能的提高,其最佳粒径范围是60μm^100μm;随着取向磁场强度的逐渐增加,磁体剩磁Br及矫顽力bHc增加较大但其内禀矫顽力iHc则基本不变;与此同时为保证磁粉取向完全,磁场取向时间必须大于5s。在此基础上,通过实验找出了最佳的装载量并制备出最大磁能积(BH)max和抗压强度σb分别为99kJ/m3及125MPa的高性能注射成形各向异性粘结NdFeB磁体。

The effect of NdFeB particle size.alignment magnetic field,alignment time and powder volume fraction on the properties of injection molding anisotropic bonded NdFeB magnet was investigated,and the reasons was also analyzed.It is found that both coarse powder and fine powder result in the deterioration of magnetic properties,and its optimal particle size is 60-100μm.As alignment magnetic field increases,the remancnce and coercivity bHc of bonded magnet tend to increase significantly whilc the coercivity jHc is almost unchanged.It is also approved that 5 seconds is necessary for the alignment time to finish particle alignment.On the basis of these,the optimal powder volume fraction is obtained and the high prop-erties injection molding anisotropic bonded NdFeB magnet is made,which its maximum energy product （BH）max and compressive strength is 99kJ/m^3,125MPa respectively.