摘要
机加工成一定尺寸和形状的烧结NdFeB薄型磁体,由于表面晶粒形变和缺陷的产生引起了磁性能的降低,适当的真空退火热处理后,其磁性能将会得到恢复和提髙。通过SEM扫描电镜,X射线衍射和磁性能的测量,研究了退火热处理对磁体表面层晶粒微结构、应变、亚晶粒尺寸和磁性能的影响。结果表明,在三相共晶点温度以上,900℃×2h+490℃×5h的退火可以完全消除机加工产生的应変、应力和缺陷。其次,表面层内晶界富Nd相的毛细管作用和扩散迁移,使富Nd相均匀、连续地分布在晶粒和晶界周围。这种富Nd相网状结构,消除了机加工磁体表层内的晶界裂纹和缺陷,对磁体性能的恢复和提高起着重要的作用。
In the article we have done the research on the influence of the annealing treatment on the surface grains' strain,micro-structure,sub-crystallite size and magnetic properties of the thin NdFeB magnet by ordering the SEM scanning electron microscope,X-ray diffraction and magnetic property measurement.The results showed that: firstly,above the three-phase eutectic temperature,900℃×2h+490×5h of annealing treatment can completely eliminate machining strain,stress and defects.Secondly,the capillary action and diffusion of the grain boundary Nd-rich phase uniformly and continuously distributed in the grains and grain boundary around.The Nd-rich phase of this network structure eliminated the grain boundary cracks and defects,and played an important role on the magnetic properties recovery and improvement.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2011年第2期347-350,共4页
Journal of Functional Materials
关键词
NDFEB
薄型磁体
磁性能
真空退火
微组织结构
应变和亚晶粒
the thin NdFeB magnet
magnetic properties
vacuum annealing
micro-structure
strain and sub-crystallite