Sandwiched structure of hot-deformed Nd-Fe-B permanent magnets processed by Nd-Cu eutectic alloys diffusion  

作　　者：Longquan Hou Jinyun Ju Xu Tang Renjie Chen Wenzong Yin Aru Yan Bin Chen Yeyuan Du 

机构地区：[1]Key Laboratory of Magnetic Materials and Devices,Ningbo Institute of Material Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China [2]Anhui Key Laboratory of Metal Materials and Processing,School of Materials Science and Engineering,Anhui University of Technology,Maanshan 243002,China

出　　处：《Journal of Rare Earths》2021年第8期993-997,共5页稀土学报（英文版）

基　　金：the National Key Research and Development Program of China(2016YFB0700902);the National Natural Science Foundation of China(51671207);the Zhejiang Province Technology Application Research Project(LGG19E010001);the Fujian Institute of Innovation,Chinese Academy of Sciences(FJCXY18040301)。

摘　　要：A series of sandwiched structures with different near-surface mass fractions x(x=3 wt%,4 wt%,5 wt%)was employed to develop high-coercivity hot-deformed Nd-Fe-B magnets by the addition of 2 wt%Nd-Cu eutectic alloys via adjusting the middle thickness and near-surface thickness.The designed magnet with a pronounced composite structure shows a 23% increase in coercivity with a 6% loss of remanence by adjusting the sandwiched structure at 4 wt% Nd-Cu eutectic alloys in the near-surface regions.The results indicate that the near-surface Nd-Cu-rich "shell" structure can effectively suppress the magnetization reversal of overall magnets,enhancing the coercivity.With the help of loading stress,Nd-Cu liquid enriched at the near-surface regions of the sample is infiltrated into the Nd-Cu-lean middle region,resulting in a concentration gradient.Microstructure characterizations further demonstrate that the infiltrated Nd-Cu eutectic plays a critical role in inhibiting grain growth and intergranular magnetic interaction.The optimized microstructure features suppress the reversed magnetization process,which makes a positive contribution to coercivity.

关 键 词：ND-FE-B Hot-deformed magnet Sandwiched structure Rare earths 

分 类 号：TG132[一般工业技术—材料科学与工程]