Magnetic properties and thermal stability of Mnbi/NdFeb hybrid bonded magnets

摘要

Magnetic properties and thermal stability were investigated for the Mnbi/NdFeb (Mnbi — 0, 20, 40, 60, 80, and 100 wt.%) bonded hybrid magnets prepared by spark plasma sintering (SPS) technique. Effect of Mnbi content on the magnetic properties of the hybrid magnets was studied. With increasing Mnbi content, the coercivity of the Mnbi/NdFeb hybrid magnets increases rapidly, while the remanence and maximum energy product drops simultaneously. Thermal stability measurement on Mnbi magnet, NdFeb magnet, and the hybrid magnet with 20 wt.% Mnbi indicates that both the NdFeb magnet and the Mnbi/NdFeb hybrid magnet have a negative temperature coefficient of coercivity, while the Mnbi magnet has a positive one. The (bH)max of the Mnbi/NdFeb magnet (Mnbi = 20 wt.%) is 5.71 MGOe at 423 K, which is much higher than 3.67 MGOe of the NdFeb magnet, indicating a remarkable improvement of thermal stability.