Characterization of Microstructure and Magnetic Properties of NdFeB Magnet with Dy, Al and Cu Additions
来源期刊：JOURNAL OF RARE EARTHS2007年增刊第1期
论文作者：Lü Yousheng Chen Yiqing Su Yong Yi Xiaofei Zhou Qingtao Xiong Yongfei Cheng Wenhao
Key words：NdFeB; microstructure; magnetic force microscope; domain structure; rare earths;
Abstract: A new alloy of Nd33.5Dy0.99Febal.Al0.52Cu0.1B1.15 (%, mass fraction) was fabricated by powder metallurgy. The effects of Dy, Al and Cu additions on the microstructure and magnetic properties of sintered NdFeB magnet were investigated. The additions of Dy, Al and Cu are effective to refine grains and improve coercivity. Moreover, suitable amounts of Dy, Al and Cu lead to a demagnetization curve with good rectangularity. It is found that the sintered NdFeB magnet has relatively high magnetic performance of Br=12.17kGs, jHc=13.52kOe and (BH)max=34.71MGOe. The sintered NdFeB sample was examined by magnetic force microscope which revealed the domain structures at the surface. It is revealed that the mean Nd2Fe14B grain size is significantly larger than the average scale of the magnetic contrast. An explanation about this is that most Nd2Fe14B grains in sintered NdFeB alloy are dominated with the muhidomain structures when the magnet is in thermally demagnetization state.
Lü Yousheng1，Chen Yiqing1，Su Yong1，Yi Xiaofei2，Zhou Qingtao1，Xiong Yongfei2，Cheng Wenhao2
(1.School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China;
2.Earth Wind Advance Magnetic Material Co., Ltd., Lujiang, Anhui, China)
Abstract:A new alloy of Nd33.5Dy0.99Febal.Al0.52Cu0.1B1.15 (%, mass fraction) was fabricated by powder metallurgy. The effects of Dy, Al and Cu additions on the microstructure and magnetic properties of sintered NdFeB magnet were investigated. The additions of Dy, Al and Cu are effective to refine grains and improve coercivity. Moreover, suitable amounts of Dy, Al and Cu lead to a demagnetization curve with good rectangularity. It is found that the sintered NdFeB magnet has relatively high magnetic performance of Br=12.17kGs, jHc=13.52kOe and (BH)max=34.71MGOe. The sintered NdFeB sample was examined by magnetic force microscope which revealed the domain structures at the surface. It is revealed that the mean Nd2Fe14B grain size is significantly larger than the average scale of the magnetic contrast. An explanation about this is that most Nd2Fe14B grains in sintered NdFeB alloy are dominated with the muhidomain structures when the magnet is in thermally demagnetization state.
Key words:NdFeB; microstructure; magnetic force microscope; domain structure; rare earths;
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