Abstract：Sintered Nd-Fe-B magnets with different grain size were fabricated by adjusting the powder particle distribution, and the influences of sintering temperature on magnetic properties were investigated. The surface of sintered magnets were coated with TbHx and then grain boundary diffusion processed, the relationship between grain size and magnetic properties of the magnets were studied. The results show that Tb atoms diffused into the edges of the Nd-Fe-B grains, which leads to magnetic hardening of the epitaxial layer of main phase grains. Moreover, Tb element uniformly distributed along grain boundary of the fine grain magnet, formed continuous heavy rare earth thin layers for demagnetization coupling, coercovity of the grain boundary diffused magnets was improved. So, the increase of coercivity is higher and decrease of remanence is small, higher performance can be obtained in the magnets with finer grain.
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2021, Vol. 28 