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采用速凝薄带加氢化工艺制备了烧结NdFeB永磁体,通过光学显微镜、扫描电镜及AMT-4磁学特性测量仪等手段表征了磁体的组织和性能,考察了回火热处理对磁体组织和性能的影响规律。研究结果表明:磁体的烧结密度、剩磁、矫顽力以及最大磁能积随一级回火温度的升高不断增大,随二级烧结温度的升高有所下降。分析认为,一级回火晶界处共晶反应使得主晶相体积分数的增加和富钕相分布均匀都进一步提高磁体的磁学性能以及磁体密度;二级回火温度升高使得富钕相再次出现偏聚,分布不再连续,造成组织不均匀,导致磁性能下降。
Sintered NdFeB permanent magnets were prepared by rapid solidification ribbon hydrogenation process. The microstructure and properties of the magnets were characterized by optical microscope, scanning electron microscopy and AMT-4 magnetic properties measuring instrument. The effects of tempering heat treatment on the microstructure and properties of the magnet, The law of performance. The results show that the sintering density, remanence, coercivity and maximum energy product increase with the increase of the first tempering temperature, but decrease with the increase of the second sintering temperature. The analysis shows that the eutectic reaction at the first tempering boundary makes the increase of the volume fraction of the main crystalline phase and the uniform distribution of the neodymium-rich phase further improve the magnetic properties and the density of the magnet. The secondary tempering temperature increases the neodymium-rich phase Segregation occurs again, the distribution is no longer continuous, resulting in uneven tissue, resulting in decreased magnetic properties.