烧结Nd－Fe－B永磁合金矫顽力机制的理论与实验研究

THEORETICAL AND EXPERIMENTAL STUDY ON COE-RCIVITY MECHANISM OF SINTERED Nd-Fe-B PERMANENT MAGNET ALLOYS

从理论和实验上研究了烧结Ｎｄ－Ｆｅ－Ｂ永磁合金的矫顽力随取向磁场的变化规律。指出磁体反磁化过程主要是晶粒边界软磁性区的反磁化成核以及反磁化核长大成畴并向晶粒内部不可逆畴壁位移的过程。比较了成核场与退钉扎场的大小及其随磁场方向的变化，并得出结论：退钉扎场是决定烧结Ｎｄ－Ｆｅ－Ｂ磁体矫顽力的主要机制。

The coercivity dependence of sintered Nd-Fe-B permanent magnet alloys on ori-enting magnetic field was studied.The results indicate that demagnetization processof the magnet is basically the nucleation process of anti-magnetization in the softmagnetization regions located at the surface of magnetic grains,and the process inwhich the nuclei grow into domains and irreversible domain wall displacement takesplace from the surface to the inside of grains.We compared the value and the var- iation dependence of nucleation field with that of depinning field on the orientationof magnetic field.we come to the conclusion that depinning field is the main mech- anism controlling the coercivity of sintered Nd-Fe-B permanent magnet alloys.