Significant effect of ordered micro-domain on cell boundary phase distribution and demagnetization curve squareness of Sm_(2)Co_(17)-type magnet  

作　　者：Zhuang Liu Hai-Chen Wu Chao-Yue Zhang Chao-Qun Zhu Guo-Xin Chen Huan-Ming Lu Ren-Jie Chen Aru Yan 

机构地区：[1]CISRI&NIMTE Joint Innovation Center for Rare Earth Permanent Magnets,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo,315201,China [2]University of Chinese Academy of Sciences,Beijing,100049,China [3]Analytical Center,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo,315201,China

出　　处：《Rare Metals》2024年第4期1724-1735,共12页稀有金属（英文版）

基　　金：financially supported by the National Key R&D Program of China(No.2021YFB3503102);Zhejiang Provincial Key R&D Program(No.2021C01191);Science and Technology Innovation 2025 Major Project of Ningbo(No.2020Z037);Ningbo Key R&D Program(No.20222ZDYF020027);Ningbo Natural Science Foundation(No.2021J216)。

摘　　要：Cu-rich cell boundary phase is difficult to precipitate evenly,resulting in a generally poor demagnetization curve squareness for Fe-rich Sm_(2)Co_(17)-type magnet,which is a key factor limiting the further improvement of magnetic energy product.In this study,we report that nanoscale strip-like ordered micro-domains distributed in1:7H disordered matrix phase of the solid solution precursor is a new factor significantly affecting the precipitation and distribution of the cell boundary phase.Long strip-like and continuous micro-twin structure with twin boundaries neatly perpendicular to the C-axis is observed after sintering treatment.After solution treatment,sequential and long strip-like micro-twins gradually transform into disordered state along the basal plane,forming narrow disordered 1:7H(TbCu_(7)-type structure)phase between the separated strip-like ordered micro-domains.This disordering transformation takes place via broken down of the long strip-like ordered micro-domains,which is accomplished by narrowing along the width direction followed by reduction of the length.Furthermore,a new model revealing the effect of the ordered micro-domains on the formation of the cell boundary phase is proposed.Antiphase boundaries enriched in Cu have already existed in the precursor with long strip-like ordered micro-domains.Therefore,the Cu-rich cell boundary phase acting as strong pinning centers cannot be precipitated homogeneously and distributed continuously after aging,resulting in a poor demagnetization curve squareness of Sm_(2)Co_(17)-type magnet.Our results indicate that significant broken down of the nanoscale ordered micro-domains in solution precursor is the key factor improving the distribution of cell boundary phase in Sm_(2)Co_(17)-type magnets.

关 键 词：Sm_(2)Co_(17) magnets Solution precursor Ordered micro-domains Disordering transformation Cellular structure 

分 类 号：TB34[一般工业技术—材料科学与工程]