放电等离子烧结热变形Nd-Fe-B磁体的磁性能研究

采用放电等离子烧结技术,利用不同速率的快淬薄带制备出各向异性的热变形Nd-Fe-B磁体,运用振动样品磁强计和扫描电子显微镜对热变形磁体的磁性能和微观结构进行研究.结果表明：随着快淬薄带速率的增加,获得最佳磁性能的热变形温度也逐渐增加,三类热变形Nd-Fe-B磁体获得最佳磁性能的热变形温度分别为650,680和700°C;磁体最佳磁性能中的剩磁和最大磁能积随着快淬薄带速率的增加而降低,而内禀矫顽力却略有增加.磁体的晶粒尺寸随着热变形温度的增加而增大;相同热变形温度下,磁体的晶粒尺寸随快淬速率的增加而减小.

The research on magnetic properties of die-upset Nd-Fe-B magnets prepared by spark plasma sintering

Using the rapid quenching thin ribbons prepared with different rates, the anisotropic die-upset Nd-Fe-B magnets were obtained by spark plasma sintering （SPS）. The magnetic properties and microstructure of die-upset Nd-Fe-B magnets were investigated by vibrating sample magnetometer （VSM） and scanning electron microscope （SEM）. The results showed that the deformation temperature of die-upset Nd-Fe-B magnets obtaining the optimum magnetic properties increased gradually with the increase in the rates of rapid quenching thin ribbons, and the deformation temperatures of three-type die-upset Nd-Fe-B magnets obtaining the optimum magnetic properties were 650, 680 and 700~C respectively. The optimum remanence and maximum energy product declined, and the optimum intrinsic coercivity of die-upset Nd-Fe-B magnets increased slightly with the increase in the rates of rapid quenching thin ribbons. The grain size of die-upset Nd-Fe-B magnets increased with the increase of deformation temperature, and decreased with the increase in the rates of rapid quenching thin ribbons under the same deformation temperature. The average grain size of die-upset Nd-Fe-B magnets decreased with the increase in the rates of rapid quenching thin ribbons when the deformation temperature was 650~C, and the grain size of die-upset Nd-Fe-B magnets produced by the rapid quenching thin ribbons with the rate of 30 m/s was homogenous, and the abnormal grain growth was not observed within the die-upset Nd-Fe-B magnets.