High-temperature magnetic properties of anisotropic MnBi/NdFeB hybrid bonded magnets

Anisotropic MnBi/NdFeB (MnBi contents of 0 wt%, 20 wt%, 40 wt%, 60 wt%, 80 wt%, and 100 wt%) hybrid bonded magnets were prepared by molding compression using MnBi powders and commercial hydrogenation disproportionation desorption and recombination (HDDR) NdFeB powders. Magnetic measurements at room temperature show that with MnBi content increasing, the magnetic properties of the MnBi/NdFeB hybrid bonded magnets all decrease gradually, while the density of the hybrid magnets improves almost linearly. In a temperature range of 293-398 K, the coercivity temperature coefficient of the hybrid magnets improves gradually from -0.59 %center dot K-1 for the pure NdFeB bonded magnet to -0.32 %center dot K-1 for the hybrid bonded magnet with 80 wt% MnBi, and the pure MnBi bonded magnet exhibits a positive coercivity temperature coefficient of 0.61 %center dot K-1.