Structure and magnetic properties of bulk nanocrystalline Nd-Fe-B permanent magnets prepared by hot pressing and hot deformation
来源期刊：JOURNAL OF RARE EARTHS2013年第7期
论文作者：宋杰 岳明 左建华 张子瑞 刘卫强 张东涛 张久兴 郭朝晖 李卫
文章页码：674 - 678
摘 要：Structure and magnetic properties were studied for bulk nanocrystalline Nd-Fe-B permanent magnets that were prepared at 650 °C for 3 min under 300 MPa using the SPS-3.20-MK-V sintering machine and the hot pressed magnets were then submitted to hot deformation with height reduction of 50%,60%,70%,80%,and 85%.Effects of height reduction（HR） and deformation temperature on the structure and magnetic properties of the magnets were investigated.The crystal structure was evaluated by means of X-ray diffraction（XRD） and the microstructure was observed by transmission electron microscopy（TEM）.The magnetic properties of the magnets were investigated by vibrating sample magnetometer（VSM）.As the height reduction increased,the remanence（B r） of the magnets increased first,peaks at 1.3 T with HR=60%,then decreased again,and the coercivity（H ci） of the magnets decreased monotonically.On the other hand,as the deformation temperature increased,the B r of the magnets increased first,peaks at 1.36 T with HR=60%,then decreased again,and the H ci of the magnets decreased monotonically.Under optimal conditions,the hot deformed magnet possessed excellent magnetic properties as B r =1.36 T,H ci =1143 kA/m,and（BH） max =370 kJ/m 3,suggesting the good potential of the magnets in practical applications.
宋杰1，岳明1，左建华1，张子瑞1，刘卫强1，张东涛1，张久兴1，郭朝晖2，李卫2
1. College of Materials Science and Engineering,Beijing University of Technology2. Division of Functional Materials,Central Iron and Steel Research Institute
摘 要：Structure and magnetic properties were studied for bulk nanocrystalline Nd-Fe-B permanent magnets that were prepared at 650 °C for 3 min under 300 MPa using the SPS-3.20-MK-V sintering machine and the hot pressed magnets were then submitted to hot deformation with height reduction of 50%,60%,70%,80%,and 85%.Effects of height reduction（HR） and deformation temperature on the structure and magnetic properties of the magnets were investigated.The crystal structure was evaluated by means of X-ray diffraction（XRD） and the microstructure was observed by transmission electron microscopy（TEM）.The magnetic properties of the magnets were investigated by vibrating sample magnetometer（VSM）.As the height reduction increased,the remanence（B r） of the magnets increased first,peaks at 1.3 T with HR=60%,then decreased again,and the coercivity（H ci） of the magnets decreased monotonically.On the other hand,as the deformation temperature increased,the B r of the magnets increased first,peaks at 1.36 T with HR=60%,then decreased again,and the H ci of the magnets decreased monotonically.Under optimal conditions,the hot deformed magnet possessed excellent magnetic properties as B r =1.36 T,H ci =1143 kA/m,and（BH） max =370 kJ/m 3,suggesting the good potential of the magnets in practical applications.
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