Suppression mechanism of abnormal grain growth by Zr addition in pressless processed Nd-Fe-B sintered magnets
Suppression mechanism of abnormal grain growth by Zr addition in pressless processed Nd-Fe-B sintered magnets
复制标题
无压加工 Nd-Fe-B 烧结磁体中添加 Zr 抑制异常晶粒长大的机制
DOI：
10.1016/j.jallcom.2021.161244
复制
发表时间：
2021
影响因子：
6.2
通讯作者：
Iriyama Takahiko
中科院分区：
文献类型：
--
作者：
Itakura Masaru;Sugiyama Koichi;Akamine Hiroshi;Nishida Minoru;Nakamura Michihide;Mizoguchi Tetsuhiko;Iriyama Takahiko
采用扫描电镜和透射电镜研究了添加Zr和不添加Zr的无压加工（PLP） Nd-Fe-B烧结磁体的显微组织。在975℃PLP烧结条件下，无zr磁体中产生了比正常晶粒尺寸大100倍的巨大多边形异常晶粒（AGs）。电子背散射衍射分析表明，PLP烧结磁体具有细小的Nd2Fe14B晶粒的双轴取向织体，且AGs的取向与双轴取向晶粒明显偏离。通过添加少量Zr，在Nd2Fe14B晶粒生长表面形成由zrb2相衍生的具有长周期堆积有序结构的片状细小Zr- b相，并具有晶体取向关系。两种富nd晶界（GB）相分别为正交Nd3（Co, Cu）和亚稳CaF2-NdO2，在烧结过程中呈液态。随着Zr-B析出相的形成，硼的消耗增加了富nd的GB相，导致液相在Nd2Fe14B晶粒周围均匀分布。因此，Zr的加入有效抑制了PLP烧结过程中由于Zr- b析出物的钉住作用和均匀液相分布形成的异常晶粒生长。
Microstructures of pressless processed (PLP) Nd-Fe-B sintered magnets with and without Zr addition were investigated by scanning electron microscopy and scanning/transmission electron microscopy. In the Zr-free magnet, huge polygonal abnormal grains (AGs) about 100 times larger than the normal grain size were generated by PLP sintering at 975 °C. Electron backscattered diffraction analysis revealed that the PLP sintered magnet had a biaxial oriented texture of fine Nd2Fe14B grains with the orientation of the AGs significantly deviated from the biaxial oriented grains. By adding a small amount of Zr, fine plate-like Zr-B precipitates with a long period stacking ordered structure derived from the ZrB2phase formed on the growth surfaces of Nd2Fe14B grains with a crystallographic orientation relationship. There were two Nd-rich grain boundary (GB) phases, namely, orthorhombic Nd3(Co, Cu) and metastable CaF2-NdO2, which became liquid during sintering. The boron consumption associated with the formation of Zr-B precipitates increased the Nd-rich GB phases, resulting in a homogeneous distribution of the liquid phase around the Nd2Fe14B grains. Therefore, the addition of Zr effectively suppressed the abnormal grain growth during PLP sintering owing to the pinning effect of the Zr-B precipitates and the formation of a homogeneous liquid phase distribution.
登录
查看更多内容
Nd-Fe-Co-B-Ga 粉末颗粒中晶域晶体取向的常规电子衍射图分析
DOI：
10.1093/oxfordjournals.jmicro.a051084
发表时间：
1994
期刊：
影响因子：
--
作者：
N. Kuwano;M. Itakura;K. Oki;R. Nakayama;T. Takeshita
通讯作者：
T. Takeshita
通过与 R1 + ϵFe4B4 化合物中的 R 原子相互作用驱动铁四面体的调制
DOI：
10.1016/0022-5088(86)90162-1
发表时间：
1986
期刊：
影响因子：
--
作者：
D. Givord;P. Tenaud;J. Moreau
通讯作者：
J. Moreau
Nd-Fe-B烧结磁体的微观结构——晶界和界面结构
DOI：
--
发表时间：
2017
期刊：
影响因子：
--
作者：
T. Sasaki;T. Ohkubo;K. Hono
通讯作者：
K. Hono
各向异性 Nd-Fe-B 磁粉 HDDR 过程中的晶体取向分析
影响因子：
2.7
作者：
R. Takizawa;M. Itakura;N. Katayama;K. Morimoto
通讯作者：
K. Morimoto
通过晶粒细化提高Nd-Fe-B烧结磁体的矫顽力
影响因子：
--
作者：
康裕 宇根;眞人 佐川
通讯作者：
眞人 佐川