【摘要】 采用放电等离子烧结技术制备了热压/热变形NdFeB磁体。研究了不同烧结温度对热压磁体、热变形磁体微观结构及磁性能的影响。结果表明,随烧结温度的升高,磁体密度上升,680℃时已达理论密度的99.7%;另一方面,晶粒则随温度的增加发生长大。剩磁和最大磁能积受密度和晶粒大小的交互作用,在650℃时达最大:(BH)m=129kJ/m3,Br=0.87T,Hci=914kA/m。热变形后,磁体主相晶粒的c轴逐渐转向与压力平行的方向,形成磁晶各向异性,使磁体的剩磁和最大磁能积大幅增加。热压烧结温度对热变形磁体的磁性能有着极大影响,其剩磁和最大磁能积随热压温度的升高先升高后降低,620℃热压后,热变形磁体磁性能达最大:(BH)m=339kJ/m3,Br=1.49T,Hci=576kA/m。更多还原

【Abstract】 Both hot-pressed and hot-deformed NdFeB magnets were prepared by spark plasma sintering technique.Effects of variable sintering temperatures on microstructures and magnetic properties of both hot-pressed and hot-deformed magnets were studied.The results showed that the density of the hot-pressed magnets increased with the sintering temperature,and reached 99.7% of theoretical density at 680℃.Besides,the grain grew up with the temperature.The remanence and the maximum energy product were influenced by the interaction of the density and grain size,which the maximum value appeared at 650℃:(BH)m=129kJ/m3,Br=0.87T,Hci=914kA/m.After hot deformation,the c-axis of the tetragonal structure gradually shifted to the direction which paralleled with pressing direction,and formed magnetocrystalline anisotropy,as a result,the remanence and the maximum energy product of the magnets increased significantly.The hot-pressed temperature has great impacts on the magnetic properties of hot-deformed magnets.With the hot-pressed temperature increasing,the remanence and the maximum energy product rose at first,and then decreased.And the hot-deformed magnets,which were hot pressed at 650℃,achieved the best magnetic properties:(BH)m=339kJ/m3,Br=1.49T,Hci=576kA/m.更多还原