Evaluation of the Microstructural Contribution to the Coercivity of Fine-Grained Nd-Fe-B Sintered Magnets
Evaluation of the Microstructural Contribution to the Coercivity of Fine-Grained Nd-Fe-B Sintered Magnets
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DOI：
10.2320/matertrans.maw201207
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发表时间：
2012-11-01
影响因子：
1.2
通讯作者：
Sagawa, Masato
中科院分区：
文献类型：
--
作者：
Fukada, Togo;Matsuura, Masashi;Sagawa, Masato
研究了晶粒细化Nd-Fe-B系烧结磁体的矫顽力与显微结构参数α和N-eff之间的关系。参数a描述了晶粒未对准和Nd 2Fe 14 B晶粒的磁晶各向异性的降低对磁性的影响。参数N-eff描述了退磁场对磁化率的影响。针对三种不同粒度且成分相同的Nd-Fe-B烧结磁体评估了这些参数。N-eff随晶粒细化而降低，而a仅随晶粒尺寸略有变化。这意味着退磁场的降低通过晶粒细化增加了磁性。然后通过纵横比、晶粒与磁化方向的角度和反圆度来评价晶粒形状和粗糙度。虽然晶粒的纵横比和角度与N-eff的变化无关，但平均反向圆度的变化与晶粒细化的N-eff的变化相对应。因此，改善粗糙度应通过晶粒细化来提高介电常数。[doi：10.2320/matertrans.MAW201207]
The relationship between coercivity and the microstructural parameters alpha and N-eff for grain refined Nd-Fe-B sintered magnets was examined. The parameter a describes the effect of grain misalignment and a decrease in the magnetocrystalline anisotropy of the Nd2Fe14B grains on the coercivity. The parameter N-eff describes the influence of the demagnetizing field on the coercivity. These parameters were evaluated for Nd-Fe-B sintered magnets with three different grain sizes and the same composition. N-eff decreased with grain refinement, while a varied only slightly with grain size. This implies that the decrease in the demagnetizing field increased the coercivity through grain refinement. Grain shape and asperity were then evaluated by the aspect ratio, angle of the grain to the direction of magnetization, and reverse circularity. Although the aspect ratio and angle of the grains were not related to the changes in N-eff, variation of the average reverse circularity corresponded to the changes in N-eff with grain refinement. Therefore, improving the asperity should increase the coercivity through grain refinement. [doi:10.2320/matertrans.MAW201207]