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本文利用1000kV超高压电镜、穆斯堡尔谱仪、X射线衍射仪和磁测量仪等对Nd-Fe-B永磁合金中的富硼相进行了研究。结果表明:富硼相以1个孤立的相存在于Nd-Fe-B永磁合金中,它一般位于基体相Nd_2Fe_(14)B的三角晶界处,占据的体积份数为4.6％,富硼相中有高密度的缺陷存在,这些缺陷的方向垂直于(?)轴。 富硼相的化学式可以写为Nd_(1+ε)Fe_4B_4(s≈0.1),该化合物由2套亚结构,即Fe-B亚结构和Nd亚结构相互套穿而成。2个亚结构均具有四方对称,在四方基面上的晶格常数相同,但沿(?)方向却有不同的周期,所以富硼相可能为一维的成分变化型无公度结构。在室温下富硼相呈顺磁性,能够在磁体中钉扎畴壁而提高矫顽力,富硼相的显微结构和温度有关,由矫顽力对温度的依赖关系和电镜观察表明富硼相对畴壁的钉扎可能属于强钉扎。
In this paper, the boron-rich phase in Nd-Fe-B permanent magnetic alloys was investigated by 1000kV UHV electron microscope, Mossbauer spectroscopy, X-ray diffraction and magnetic measuring instrument. The results show that the boron-rich phase exists as an isolated phase in the Nd-Fe-B permanent magnet alloy, which is generally located at the triangular grain boundary of Nd 2 Fe 14 B, occupying 4.6% of the volume fraction, High-density defects exist in the boron phase, with the orientation of these defects perpendicular to the (?) Axis. The chemical formula of the boron-rich phase can be written as Nd_ (1 + ε) Fe_4B_4 (s≈0.1). The compound is composed of two sets of sub-structures, ie, the Fe-B sub-structure and the Nd sub-structure. The two substructures all have tetragonal symmetry, with the same lattice constant on the tetragonal base plane, but different periods along the (?) Direction. Therefore, the boron-rich phase may be a one-dimensional compositional variation degree of uncoordinated structure. The boron-rich phase is paramagnetic at room temperature, capable of pinning the domain wall in the magnet to increase the coercivity. The microstructure of the boron-rich phase is related to temperature. The dependence of coercivity on temperature and electron microscopy indicate that boron Pinning relative domain walls may be strongly pinned.