Coercivity enhancement of sintered Nd-Fe-B magnets by grain boundary diffusion with DyH3 nanoparticles
首发时间:2012-12-20
Abstract:Ggrain boundary diffusion technique with DyH3 nanoparticles was applied to fabricate Dy-less sintered Nd-Fe-B permanent magnets with high coercivity. The magnetic properties and microstructure of magnets were systematically studied. The coercivity and remanence of grain boundary diffusion magnet were improved by 60% and reduced by 7% compared with those of the original magnet, respectively. Meanwhile, both the remanence temperature coefficient (α) and the coercivity temperature coefficient (β) of the magnets were improved after diffusion treatment. Investigation shows that Dy is preferentially enriched as (Nd, Dy)2Fe14B phase in the surface region of the Nd2Fe14B matrix grains indicated by the remarkable enhancement of the magneto-crystalline anisotropy field of the magnet. As a result, the magnet diffused with a small amount of Dy nanoparticles possesses enhanced coercivity without sacrificing its magnetization.
keywords: Grain boundary diffusion DyH3 nanoparticles Coercivity Thermal stability
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DyH3纳米颗粒晶界扩散制备高矫顽力烧结Nd-Fe-B磁体
摘要:采用DyH3纳米颗粒晶界扩散技术制备了低Dy含量高矫顽力烧结Nd-Fe-B磁体,系统研究了DyH3纳米颗粒晶界扩散磁体的磁性能和微观组织结构。经DyH3纳米颗粒晶界扩散后磁体的矫顽力提高了60%,剩磁降低了7%。同时磁体的剩磁温度系数和矫顽力温度系数均明显改善。显微组织结果表明Dy以(Nd, Dy)2Fe14B相的形式优先富集在主相晶粒外延层,从而提高了磁体的磁晶各向异性场。因此少量的DyH3纳米颗粒晶界扩散可以显著提高矫顽力而磁性能降低幅度较小。
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