粒度及其分布对永磁铁氧体性能参数的影响规律研究

Study on Effects of the Granularity and Size Distribution on the parameters of Permanent Magnetic Ferrites

用比较试验法结合正交法验证了粒度及其分布对永磁铁氧体各参数的影响规律。当永磁铁氧体成型用微纳颗粒料从较粗的状态(如1.60μm)逐渐减小时,粒度对磁体的收缩率、剩磁B_r、内秉矫顽力H_(cj)的影响作用逐渐减弱,当粒度减小到一定程度(如0.78μm)之后,再进一步下降时,粒度对H_(cj)的影响作用则显著增强,当粒度从0.63μm进一步下降到0.50μm时,粒度对磁体的收缩率、剩磁B_r的影响作用显著增强;实验进一步发现,成型用料浆粒度分布越差,超细颗粒越多,影响最大的是磁体的H_(cj),在其他工艺条件均相同时,可以根据产品H_(cj)是否得到有效改善来判定料浆的粒度分布是否得到有效受控。

This study verifies the effects of the particle size and size distribution on the parameters of permanent magnetic ferrite by comparison test in combinination of orthogonal method. When the micro-nano granularity used for the permanent magnetic ferrite molding reduce gradually from the coarser size （such as 1.60 μm）, the granularity has decreasing weaker effects on the magnet shrinkage rate, residual magnetism Br, and the coercive force Hcj. However, when the granularity reduces to a certain extent （such as 0.78 μm） and then furtherly reduces, the granularity has an increasing significant effect on Hcj;when the granularity reduces from 0.63 μ m further to 0.50 μ m, the granularity has increasing significant effects on the shrinkage rate of magnets and the remanence Br. The further experiment finds that the worse granularity distribution of the molding slurry and the more ultrafine particles, the Hcj is the most influenced. Therefore, under the same time process conditions, whether Hcj is effectively improved can be used to determine whether the slurry granularity distribution is effectively controlled.