晶界添加Dy79.73Fe20.27对烧结钕铁硼微观结构和磁性能的影响  

Effect of Dy79.73Fe20.27 Addition in the Grain Boundary on the Microstructure and Magnetic Properties of Sintered Nd-Fe-B Magnets

作　　者：宋小明 张廷安[2] 裴文利 豆志河[2] 周廉 SONG Xiao-ming;ZHANG Ting-an;PEI Wen-li;DOU Zhi-he;ZHOU Lian(School of Materials Science and Engineering,Northeast University,Shenyang 110006,China;School of Metallurgy,Northeast University,Shenyang 110006,China;Ningbo Qiyuan New Materials Technology Co.,Ltd.,ISingbo 315040,China)

机构地区：[1]东北大学材料科学与工程学院,辽宁沈阳110006 [2]东北大学冶金学院,辽宁沈阳110006 [3]宁波启元新材料科技有限公司,浙江宁波315040

出　　处：《稀土》2020年第3期10-16,共7页Chinese Rare Earths

基　　金：国家自然科学基金项目(51871045)。

摘　　要：晶界扩散提高烧结钕铁硼矫顽力优势明显,由于其工艺特性,对被扩散的磁体有尺寸限制,且需要专门设备和工序,使其在实际推广中受到一定限制。一些文献报道了通过直接晶界添加含Dy等重稀土合金扩散源,该工艺不再受尺寸限制,可取得类似扩散的结果,只是合金需专门制作。直接晶界添加容易得到的烧结钕铁硼磁体生产常用的原材料Dy80Fe20(质量分数)合金,又省略了制备Dy合金工序,实验采用的实际合金是Dy79.73Fe20.27,同时将一级回火时间由原来的3 h加长到7 h。一方面补充了晶界相,使晶界更加清晰、完整、连续,去耦合效果更好,磁体Hcj提高;另一方面晶粒表面生成(Pr,Nd,Dy)2Fe14B,形成核壳结构,得到类似Dy扩散的效果,使磁体Hcj有效提升。Hcj综合提升效果优于其他文献晶界添加报告值。该工艺生产过程不再受毛坯尺寸限制,可以制得大块磁体。得到磁体性能为Br=13.89 kGs、Hcj=21.32 kOe、(BH)max=47.43 MGOe。对实际批产具有指导意义。The advantages of grain boundary diffusion in improving coercivity of sintered NdFeB magnets are vast.However,due to the need for special equipment and processes,and the size limitations of diffused magnets,the practicality of grain boundary diffusion is limited.Some literatures reported adding Dy-containing alloys to the grain boundary directly,the magnets are no longer limited by size,and similar diffusive results can be obtained,but the alloys need to be specially fabricated.The process of preparing the Dy alloy and special equipment can be omitted also,we choose easier to obtain the Dy80Fe20(mass fraction)alloy,which is the raw material for sintered Nd-Fe-B magnet production,the actual alloy used in the experiment is Dy79.73Fe20.27.The first annealing time is extended from 3 h to 7 h,simultaneously.In this method of grain boundary supplementation there are many advantages:the grain boundary is clearer,more complete and continuous,the decoupling effect is better,and Hcj is improved.Moreover,Dy introduced into the magnet grain surface forms a thin(Pr,Nd,Dy)2Fe14B hard magnetic shell to effectively improve Hcj.The improvement of Hcj obtained by the research is better than that reported in some literatures.This process is no longer limited by the size of the magnets and can produce larger magnets,and it does not need the special equipment.The sintered Nd-Fe-B magnets with magnetic properties of Br=13.89 kGs Hcj=21.32 kOe,and(BH)max=47.43 MGOe was obtained.This process also has guiding significance for actual batch production.

关 键 词：烧结ND-FE-B磁体 晶界添加 晶界扩散 磁性能 

分 类 号：TM273[一般工业技术—材料科学与工程]