Abstract：A layer of Tb coating was deposited on the surface of sintered NdFeB magnets by magnetron sputtering, and then grain boundary diffusion heat treatment was carried out to prepare grain boundary diffusion (Tb,Nd)FeB magnets. The microstructure and magnetic properties of the magnets before and after grain boundary diffusion were analyzed by scanning electron microscope, electron probe microanalyzer and hysteresis loop measurement instrument. Results show that (Tb,Nd)FeB magnets prepared by grain boundary diffusion method have wider grain boundary phases than NdFeB magnets. The grain boundary phases are continuously distributed around the main phase grains, which plays a demagnetizing coupling role. And the heavy rare earth element Tb distributed on the surface of the main phase grains forms (Tb,Nd)FeB phases with higher magnetocrystalline anisotropy field. The intrinsic coercivity Hcj of (Tb,Nd)FeB magnets is significantly increased, and its Hcj increases from 15.98 kOe to 23.78 kOe of NdFeB magnets.
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2021, Vol. 28 