以MQU-F(Magnequench ultra-fine)磁粉为原料,经热压制+模压成形得到模压成形Nd-Fe-B磁体,随后以Pr_(70)Cu_(30)共晶合金为扩散源,在不同压力下(0、10、20 k Pa)对磁体进行压力辅助晶界扩散处理。研究发现,晶界扩散后,钕铁硼磁体的矫顽...以MQU-F(Magnequench ultra-fine)磁粉为原料,经热压制+模压成形得到模压成形Nd-Fe-B磁体,随后以Pr_(70)Cu_(30)共晶合金为扩散源,在不同压力下(0、10、20 k Pa)对磁体进行压力辅助晶界扩散处理。研究发现,晶界扩散后,钕铁硼磁体的矫顽力显著提升,但剩磁会降低。在微观结构方面,富钕相体积分数增加且在界面局部富集,于主相晶粒边界形成隔离层,增强富钕相钉扎作用,提升矫顽力;但富钕相过量致使主相晶粒取向一致性下降,导致剩磁衰减。此外,辅助压力增加时,矫顽力不断提升,剩磁则不断衰减。压力能够促进Pr、Cu元素渗透,优化非铁磁性晶间相网络形成,但也会引起主相晶粒局部取向杂乱。在微观结构上,压力使富钕相分布更连续,晶粒细化,优化微观结构均匀性。压力增大还能促进熔融扩散源向磁体心部渗透,Pr、Cu元素主要富集在距表面1.5 mm范围内,其含量随压力增加而增加,且增加压力提升了元素沿晶界网络的扩散效率,元素含量随深度分布曲线斜率变大。展开更多
To improve the overall magnetic properties of Sm(CoFeCuZr)_(z)sintered magnets,a dual-alloy sintering process that involves mixing high-iron,low-copper powders with low-iron,high-copper powders was systematically inve...To improve the overall magnetic properties of Sm(CoFeCuZr)_(z)sintered magnets,a dual-alloy sintering process that involves mixing high-iron,low-copper powders with low-iron,high-copper powders was systematically investigated.The results demonstrate that this method significantly improves the Cu-lean phenomenon at the grain boundaries,achieves multiscale uniform microstructures,greatly enhances the pinning field strength,and ultimately produces a high-performance dual-alloy magnet with a maximum energy product((BH)_(max))exceeding 240 kJ/m^(3)and an intrinsic coercivity(H_(cj))exceeding 2400 kA/m.In particular,when 35 wt.%of low-iron,high-copper alloy powder is incorporated,the dual-alloy magnet achieves a remanence of 1.13 T,H_(cj)of 2691.2 kA/m and(BH)_(max)of 248 kJ/m^(3).To evaluate the overall magnetic performance,the sum of H_(cj)(in kA/m)and(BH)_(max)(in kJ/m^(3))is used as a combined parameter,yielding a value of 2939.2.Compared with single-alloy magnets of the same composition,the dual-alloy sintering process yields magnets with a more uniform elemental distribution and superior magnetic properties.展开更多
文摘以MQU-F(Magnequench ultra-fine)磁粉为原料,经热压制+模压成形得到模压成形Nd-Fe-B磁体,随后以Pr_(70)Cu_(30)共晶合金为扩散源,在不同压力下(0、10、20 k Pa)对磁体进行压力辅助晶界扩散处理。研究发现,晶界扩散后,钕铁硼磁体的矫顽力显著提升,但剩磁会降低。在微观结构方面,富钕相体积分数增加且在界面局部富集,于主相晶粒边界形成隔离层,增强富钕相钉扎作用,提升矫顽力;但富钕相过量致使主相晶粒取向一致性下降,导致剩磁衰减。此外,辅助压力增加时,矫顽力不断提升,剩磁则不断衰减。压力能够促进Pr、Cu元素渗透,优化非铁磁性晶间相网络形成,但也会引起主相晶粒局部取向杂乱。在微观结构上,压力使富钕相分布更连续,晶粒细化,优化微观结构均匀性。压力增大还能促进熔融扩散源向磁体心部渗透,Pr、Cu元素主要富集在距表面1.5 mm范围内,其含量随压力增加而增加,且增加压力提升了元素沿晶界网络的扩散效率,元素含量随深度分布曲线斜率变大。
基金supported by the National Key Research and Development Program for Young Scientists,China(No.2023YFB3508400)the National Natural Science Foundation of China(Nos.51871005,51931007)+1 种基金the Key Program of Science and Technology Development Project of Beijing Municipal Education Commission of China(No.KZ202010005009)the Program of Top Disciplines Construction in Beijing,China(No.PXM2019_014204_500031)。
文摘To improve the overall magnetic properties of Sm(CoFeCuZr)_(z)sintered magnets,a dual-alloy sintering process that involves mixing high-iron,low-copper powders with low-iron,high-copper powders was systematically investigated.The results demonstrate that this method significantly improves the Cu-lean phenomenon at the grain boundaries,achieves multiscale uniform microstructures,greatly enhances the pinning field strength,and ultimately produces a high-performance dual-alloy magnet with a maximum energy product((BH)_(max))exceeding 240 kJ/m^(3)and an intrinsic coercivity(H_(cj))exceeding 2400 kA/m.In particular,when 35 wt.%of low-iron,high-copper alloy powder is incorporated,the dual-alloy magnet achieves a remanence of 1.13 T,H_(cj)of 2691.2 kA/m and(BH)_(max)of 248 kJ/m^(3).To evaluate the overall magnetic performance,the sum of H_(cj)(in kA/m)and(BH)_(max)(in kJ/m^(3))is used as a combined parameter,yielding a value of 2939.2.Compared with single-alloy magnets of the same composition,the dual-alloy sintering process yields magnets with a more uniform elemental distribution and superior magnetic properties.
