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
• 来源期刊: 稀土学报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: MAGNETISM AND MAGNETIC MATERIALS
• 页码范围: 993-997
• 页数: 5页
• 语种: 英文

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.