Nd-Fe-B基纳米复合永磁材料矫顽力及其机制的研究进展

Research Progress of Coercivity and Coercivity Mechanism of Nd-Fe-B Based Nanocomposite Permanent Magnets

摘要:

重点探讨Nd-Fe-B基纳米复合永磁材料晶间交换耦合作用对有效各向异性和矫顽力的影响，对Nd-Fe-B基纳米复合永磁材料矫顽力机制进行讨论分析。硬磁相之间的耦合在反磁化场作用下将促进畴壁位移和磁距反转，不利于提高纳米复合永磁材料的矫顽力，在晶间形成适当的非磁性相减弱硬磁相之间的耦合作用可一定程度地提高纳米复合永磁材料矫顽力。除形核场、自钉扎作用外，晶粒内部缺陷的钉扎效应能阻止反磁化畴壁的位移，可进一步提高纳米复合永磁材料矫顽力

Abstract:

The effects of the exchange-coupling between nano-grains on effective anisotropy and coercivity of Nd-Fe-B based nanocomposite permanent magnets were discussed, and the coercivity mechanism of the magnets was also analyzed. The exchange-coupling between hard grains promotes the movement of domain walls and the reversal of magnetic moment at the applied field, which decreases the coercivity of nanocomposite magnets. Therefore, nonmagnetic grain boundary phases with suitable thickness can weaken the exchange-coupling between nano-grains of hard magnetic phase to improve the coercivity of nanocomposite permanent magnets. Besides the nucleation field and self-pining, the pining effect of nonmagnetic precipitates distributed in grains may impede the movement of the domain walls to further increase the coercivity of nanocomposite magnets.