Relationship between controllable preparation and microstructure of NdFeB sintered magnets
来源期刊：JOURNAL OF RARE EARTHS2014年第7期
论文作者：李岩峰 朱明刚 李安华 冯海波 黄书林 李卫 杜安 齐岩
文章页码：628 - 632
摘 要：The double hard magnetic phase magnets with nominal compositions of Nd30–xDyxFe69B1（x=2, and 4）（wt.%） were prepared. The magnetic properties of the magnets were measured with a NIM-2000H hysteresigraph. The crystalline structures of the magnets were identified by X-ray diffraction（XRD）. The Rietveld refinement was carried out using the FULLPROF software. The scanning electron microscopy（SEM） and transmission electron microscopy（TEM） analyses were carried out in order to investigate the microstructure of the magnets. It showed that the magnets consisted mainly of Nd2Fe14 B phase, and some Nd-rich phase. Two types of matrix-phase grains in dark grey and light grey were found in the magnets with x=2 and 4. The Dy content was obviously different in the two types of grains, which proved that the double hard magnetic phases（Dy-rich and Dy-lean phases） coexisted in the magnet. It revealed that the Nd-rich phases in junction regions had fcc structure, with the unit cell parameter of about 0.52–0.56 nm. The weak superlattice spots were found in the SAD patterns of the junction Nd-rich phases with large scale. The double hard magnetic phase structure seemed to improve the magnetic properties of NdFeB magnets with high coercivity, while decrease the consumption of Dy element, compared with the single alloy magnet.
李岩峰1,2，朱明刚1，李安华1，冯海波1，黄书林1，李卫1，杜安2，齐岩2
1. Division of Functional Materials,Central Iron and Steel Research Institute2. College of Science,Northeastern University
摘 要：The double hard magnetic phase magnets with nominal compositions of Nd30–xDyxFe69B1（x=2, and 4）（wt.%） were prepared. The magnetic properties of the magnets were measured with a NIM-2000H hysteresigraph. The crystalline structures of the magnets were identified by X-ray diffraction（XRD）. The Rietveld refinement was carried out using the FULLPROF software. The scanning electron microscopy（SEM） and transmission electron microscopy（TEM） analyses were carried out in order to investigate the microstructure of the magnets. It showed that the magnets consisted mainly of Nd2Fe14 B phase, and some Nd-rich phase. Two types of matrix-phase grains in dark grey and light grey were found in the magnets with x=2 and 4. The Dy content was obviously different in the two types of grains, which proved that the double hard magnetic phases（Dy-rich and Dy-lean phases） coexisted in the magnet. It revealed that the Nd-rich phases in junction regions had fcc structure, with the unit cell parameter of about 0.52–0.56 nm. The weak superlattice spots were found in the SAD patterns of the junction Nd-rich phases with large scale. The double hard magnetic phase structure seemed to improve the magnetic properties of NdFeB magnets with high coercivity, while decrease the consumption of Dy element, compared with the single alloy magnet.
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