Magnetic Properties and Dysprosium Infiltration of Sintered Nd-Fe-B Magnets by Magnetron Sputtering
LI Jiajie1,2, GUO Chengjun1, ZHOU Toujun1, RAO Xianfa1, ZHOU Huijie3, YANG Bin1,2
1 Institute of Engineering and Research, Jiangxi University of Science and Technology, Ganzhou 341000; 2 School of Material Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000; 3 Ganzhou Qiandong Rare Earth Group Co., Ltd, Ganzhou 341000
Abstract: The Dy films on the surface of sintered Nd-Fe-B magnets were prepared by DC magnetron sputtering. The microstructure and properties of N35 as-sintered state and tempered state magnets were compared after grain boundary diffusion. The coercivities of as-sintered and tempered state magnets increased drastically by 708.44 kA/m and 665.46 kA/m in the case of remanences decrease of only 0.009 T and 0.03 T respectively after sputtering Dy infiltration treatment. The increment of Dy contents in magnets did not exceed 0.4% (the average mass fraction) after Dy infiltration process. The improvement of coercivity is attributed to the formation of grain boundary microstructure and (Nd,Dy)2Fe14B epitaxial layer via SEM and EDS analysis. The EPMA elemental surface distribution results show that Dy mainly enriches in Nd-rich phases. The concentration of Dy is the highest especially in the trigeminal type Nd-rich phases while Dy elements have not spread into the main phases. It will not significantly reduce remanence of the magnets so that the integrated magnetic properties are improved effectively.
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2017, Vol. 31 
