摘要
The phase structure and magnetic properties of high-Co containing permanent magnets with high thermal stability have been systematically studied in this work.It is abnormal that the coercivity of annealed samples was slightly lower than that of sintered samples,while the coercivity was usually enhanced after annealing in conventional Nd–Fe–B samples.Further analysis showed that in addition to RE2(Fe,Co)14B main phase and RE-rich grain boundary phase,there were also new Co-rich magnetic phases located in the grain boundary.During annealing,the phase structures of high-Co containing magnets were readjusted,especially the increasing Co-rich magnetic phase and emerging RE-rich particles precipitated from the main phase.Eventually,the isolated RE-rich particles would act as the pinning center of the domain wall movement in demagnetization process.It was confirmed that the coercivity of annealed high-Co containing magnets was controlled by both nucleation and pinning.Pinning mechanism can partially compensate for the weakening of magnetic isolation due to increased Co-rich magnetic phase,which explained the moderate decrease in coercivity of annealed high-Co containing magnets.The discovery of new coercivity mechanism contributed to in-depth understanding of high-Co containing magnets.
作者
Min Huang
Yong Ding
Zhihe Zhao
Chunguo Wang
Bo Zhou
Lei Liu
Yingli Sun
Aru Yan
黄敏;丁勇;赵之赫;王春国;周波;刘雷;孙颖莉;闫阿儒(CISRI & NIMTE Joint Innovation Center for Rare Earth Permanent Magnets,CAS Key Laboratory of Magnetic Materials and Devices,Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China;University of Chinese Academy of Sciences,Beijing 100049,China)
基金
Project supported by National Key R&D Program of China(Grant No.2021YFB3803003)
Youth Innovation Promotion Association CAS(Grant No.2023311).
