Abstract:Sintered NdFeB magnets with different nano Al doping content were prepared by adding different nano Al into NdFeB fine powder by intergranular doping method. The effects of nano Al doping on the microstructure, magnetic properties and temperature stability of sintered NdFeB magnets were systematically studied. Results show that the coercivity of the magnets can be significantly improved by doping nano Al. The coercivity increases from 8.91 kOe when undoped nano Al to 12.34 kOe when doped with 0.8 wt% nano Al. However, the doping of nano Al will also reduce the remanence and magnetic energy product of the magnets. The doping of nano Al can improve the temperature stability of the magnets. Due to the low melting point of nano Al, doping nano Al can not only help the liquid phase sintering of sintered magnets and promote its densification, but also reduce the massive rare earth rich phases and increase the lamellar rare earth rich phases, which plays a demagnetizing coupling role and an important role in the magnetic hardening of sintered magnets.