Study on Resistivity and Magnetic Properties of Hot Deformed NdFeB Magnets by Aluminum Nitride Doping

In order to accelerate the development of high-speed permanent magnet motor and improve the resistivity of NdFeB, it is very important to improve the service stability and prolong the service life of permanent magnet rotor NdFeB permanent magnet. The high resistivity AlN doping was used to improve the resistivity of thermally deformed NdFeB magnets.After mixing AlN and NdFeB fast quenching powder evenly, NdFeB magnets with different mass fractions of AlN were prepared by hot pressing and hot deformation molding method. The effects of AlN doping on the hot pressing compactness, resistivity and magnetic properties of hot pressing and hot deformation NdFeB magnets were studied. The results show that with the increase of the mass fraction of AlN, the density of the hot-pressed magnet decreases gradually, and the resistivity of the heat-deformed magnet increases gradually, but the magnetic properties of the hot-deformed magnet decrease linearly.When the mass fraction of AlN is 1%, the magnetic energy decreases obviously, the remanence is 1.175 T, the coercivity is 511.7 kA/m, the maximum magnetic energy product is 196.0 kJ/m³, the magnetic energy decreases by about 50%,and the loss is obvious.The resistivity is 257 μΩ·cm, which is 11.7% higher than that of without doping thermal deformation NdFeB magnets（230 μΩ·cm）