Dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets  

作　　者：Longlong Xi Anhua Li Haibo Feng Min Tan Wei Sun Minggang Zhu Wei Li 

机构地区：[1]Division of Functional Materials,Central Iron and Steel Research Institute,Beijing 100081,China [2]National Engineering Research Center for Magnetic Materials,Beijing 102600,China

出　　处：《Journal of Rare Earths》2019年第8期865-870,I0003,共7页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(51590882);the Plan of National Key Research and Development of China(2016YFB0700903)

摘　　要：In this paper,dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets with Cu-doped Ce-rich alloy addition was investigated.It shows that the maximum energy product(BH)(max)and coercivity H(cj)of Ce-Fe-B sintered magnet are improved from 6.76 to 9.13 MGOe by 35.1%,and from 1.44 to 1.67 kOe by 16.0%,respectively,via adding 5 wt%liquid phase alloy of Ce(35.58)Fe(57.47)Cu6 B(0.95)(at%).Compared with the magnet without Cerich alloy addition,the volume fraction of the grain-boundary phase with low melting point increases in the magnet with Ce-rich alloy additio n,which is be ne ficial to imp roving the microstructure and promoting the coercivity enhancement of the magnet.In the Ce-Fe-B magnet with Ce-rich alloy addition,Cu and Ce enrich in the grain boundaries of the magnet after annealing,therefore the as-annealed magnet has a higher coercivity than the as-sintered magnet.A distinct Fe-rich layer with the average thickness of 60 nm is found in the grain boundaries in the magnet without Ce-rich alloy addition,but it seems that Fe-rich phase disappears in the magnet with Ce-rich alloy addition.The present work suggests that the further improvement of coercivity in the Ce-Fe-B sintered magnets is expectable by designing the composition and structure of added liquid phase alloys.In this paper,dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets with Cu-doped Ce-rich alloy addition was investigated.It shows that the maximum energy product（BH）max and coercivity Hcj of Ce-Fe-B sintered magnet are improved from 6.76 to 9.13 MGOe by 35.1%,and from 1.44 to 1.67 kOe by 16.0%,respectively,via adding 5 wt% liquid phase alloy of Ce35.58Fe57.47Cu6 B0.95（at%）.Compared with the magnet without Cerich alloy addition,the volume fraction of the grain-boundary phase with low melting point increases in the magnet with Ce-rich alloy additio n,which is be ne ficial to imp roving the microstructure and promoting the coercivity enhancement of the magnet.In the Ce-Fe-B magnet with Ce-rich alloy addition,Cu and Ce enrich in the grain boundaries of the magnet after annealing,therefore the as-annealed magnet has a higher coercivity than the as-sintered magnet.A distinct Fe-rich layer with the average thickness of 60 nm is found in the grain boundaries in the magnet without Ce-rich alloy addition,but it seems that Fe-rich phase disappears in the magnet with Ce-rich alloy addition.The present work suggests that the further improvement of coercivity in the Ce-Fe-B sintered magnets is expectable by designing the composition and structure of added liquid phase alloys.

关 键 词：Ce-Fe-B Ce-rich liquid phase alloy Cu doping MICROSTRUCTURE COERCIVITY RARE earths 

分 类 号：TG1[金属学及工艺—金属学]