A systemic investigation was done on the chemistry and crystal structure of boundary phases in sintered Ce9Nd21FebalB1 （wt%） magnets. Ce2Fe14B is believed to be more soluble in the rare-earth （RE）-rich liquid phas...A systemic investigation was done on the chemistry and crystal structure of boundary phases in sintered Ce9Nd21FebalB1 （wt%） magnets. Ce2Fe14B is believed to be more soluble in the rare-earth （RE）-rich liquid phase during the sintering process. Thus, the grain size and oxygen content were controlled via low-temperature sintering, resulting in high coercivity and maximum energy products. In addition, Ce formed massive agglomerations at the triple-point junctions, as confirmed by elemental mapping results. Transmission electron micros- copy （TEM） images indicated the presence of （Ce,Nd）Ox phases at grain boundaries. By controlling the composition and optimizing the preparation process, we successfully obtained Ce9Nd21FebalBx sintered magnets; the prepared magnets exhibited a residual induction, coerciv- ity, and energy product of 1.353 T, 759 kA/m, and 342 kJ/m3, respectively.展开更多
Magnets with nominal compositions of （ Nd1-x Cex ） 30 Febal Cu0.1 B1 （x = 0, 0.15, 0.3 and 0.4, mass% ） have been fabricated by blending powder method. The remanence （B r）, intrinsic coercivity （He） and maximu...Magnets with nominal compositions of （ Nd1-x Cex ） 30 Febal Cu0.1 B1 （x = 0, 0.15, 0.3 and 0.4, mass% ） have been fabricated by blending powder method. The remanence （B r）, intrinsic coercivity （He） and maximum en- ergy product （BH） of the RE2Fe14B type magnets deteriorated when Nd was replaced by Ce. The chemical composition and crystal structure of magnet were investigated systemically. Backscattered electron （BSE） and energy dispersive spectroscopy （EDS） results revealed that Ce-rich and Ce-lean matrix grains coexisted in the magnets. The magnetic coupling mechanism among the double hard magnetic phases was discussed. Low melting point RE-Cu phase was in favor of the formation of uniform continuous grain boundary. Transmission electron microscopy （TEM） investigation showed the presence of fcc （Nd,Ce）Ox phase in the grain boundary. When the Ce content was 15% of the total amounts of all the rare earth, the maximum energy product of the sintered magnet was 359.8 kJ/ms.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51171048)the National High Technology Research and Development Program of China (No. 2014CB643701)the National Science and Technology Support Program of China (No. 2012BAE02B01)
文摘A systemic investigation was done on the chemistry and crystal structure of boundary phases in sintered Ce9Nd21FebalB1 （wt%） magnets. Ce2Fe14B is believed to be more soluble in the rare-earth （RE）-rich liquid phase during the sintering process. Thus, the grain size and oxygen content were controlled via low-temperature sintering, resulting in high coercivity and maximum energy products. In addition, Ce formed massive agglomerations at the triple-point junctions, as confirmed by elemental mapping results. Transmission electron micros- copy （TEM） images indicated the presence of （Ce,Nd）Ox phases at grain boundaries. By controlling the composition and optimizing the preparation process, we successfully obtained Ce9Nd21FebalBx sintered magnets; the prepared magnets exhibited a residual induction, coerciv- ity, and energy product of 1.353 T, 759 kA/m, and 342 kJ/m3, respectively.
基金Item Sponsored by National Natural Science Foundation of China(51171048)National High Technology Research and Development Program of China(2014CB643701)National Science and Technology Support Program of China(2012BAE02B01)
文摘Magnets with nominal compositions of （ Nd1-x Cex ） 30 Febal Cu0.1 B1 （x = 0, 0.15, 0.3 and 0.4, mass% ） have been fabricated by blending powder method. The remanence （B r）, intrinsic coercivity （He） and maximum en- ergy product （BH） of the RE2Fe14B type magnets deteriorated when Nd was replaced by Ce. The chemical composition and crystal structure of magnet were investigated systemically. Backscattered electron （BSE） and energy dispersive spectroscopy （EDS） results revealed that Ce-rich and Ce-lean matrix grains coexisted in the magnets. The magnetic coupling mechanism among the double hard magnetic phases was discussed. Low melting point RE-Cu phase was in favor of the formation of uniform continuous grain boundary. Transmission electron microscopy （TEM） investigation showed the presence of fcc （Nd,Ce）Ox phase in the grain boundary. When the Ce content was 15% of the total amounts of all the rare earth, the maximum energy product of the sintered magnet was 359.8 kJ/ms.
