Influences of Oxidation State of Nd-Rich Phase on the Coercivity of Nd-Fe-B/Nd Thin Films
Influences of Oxidation State of Nd-Rich Phase on the Coercivity of Nd-Fe-B/Nd Thin Films
复制标题
富Nd相氧化态对Nd-Fe-B/Nd薄膜矫顽力的影响
DOI：
10.2320/matertrans.maw200913
复制
发表时间：
2009
影响因子：
1.2
通讯作者：
S. Sugimoto
中科院分区：
文献类型：
--
作者：
M. Matsuura;T. Fukada;R. Goto;N. Tezuka;S. Sugimoto
Nd-Fe-B系烧结磁体中的富Nd相含有一定量的氧，对磁体的磁性能起着重要的作用。但Nd 2Fe 14 B与富Nd相之间的界面结构对其影响尚不清楚。本文采用薄膜技术制备了Nd 2Fe 14 B/Nd（-O）界面，研究了富Nd相的氧化态对界面性能的影响。采用超高真空（UHV）磁控溅射法沉积Nd-Fe-B层，并在低真空（低氧化态）或Ar气氛（高氧化态）下对薄膜进行氧化。在氧化的Nd-Fe-B层上沉积Nd层，并在250-650°C下退火60 min。经250-650°C退火后，低氧化态氧化膜的磁性得到恢复，350°C退火后，在Nd 2Fe 14 B与六方晶系Nd 203（+ fcc NdOx）相的界面处观察到非晶相。另一方面，高氧化态氧化的薄膜的极化率比低氧化态氧化的薄膜的极化率低，在250-350°C退火后，极化率下降了20%左右。然而，在这些膜的界面处没有观察到非晶相。在高于550°C的温度下退火后，在低氧化态和高氧化态下氧化的膜的矫顽力急剧恢复到与沉积态膜几乎相同的值。从透射电镜的SAD图可以看出，薄膜中的富Nd相中存在亚稳的C-Nd 2 O3相。此外，已知富Nd相的润湿性在约550°C的温度下改善。因此，认为矫顽力的提高与富Nd相流动性的改善或C-Nd 2 O3相的存在有关。
The Nd-rich phase of Nd-Fe-B sintered magnets, which contains some amount of oxygen, plays an important role for generating coercivity. However, the influence of interfacial microstructure between Nd 2 Fe 14 B and Nd-rich phases has not been clear. In this study, Nd 2 Fe 14 B/Nd(-O) interface was prepared by thin film technique and the influence of oxidation state of Nd-rich phase on the coercivity was investigated. A Nd-Fe-B layer was deposited by ultra high vacuum (UHV) magnetron sputtering, and the film was oxidized under low vacuum condition (low oxidation state) or Ar atmosphere (high oxidation state). A Nd layer was deposited on the oxidized Nd-Fe-B layer, and the film was annealed at 250-650°C for 60min. The coercivity of films oxidized in low oxidation state was recovered by annealing at 250-650°C, and an amorphous phase was observed at the interface between Nd 2 Fe 14 B and hcp Nd 2 0 3 (+ fcc NdO x ) phases in the film annealed at 350°C. On the other hand, the coercivity of films oxidized in high oxidation state was lower than that of films oxidized in low oxidation state, and it decreased more about 20% by annealing at 250-350°C. However, an amorphous phase was not observed at the interface of these films. After annealing above 550°C, the coercivity of films oxidized in both low and high oxidation state recovered drastically to the almost same value of as-deposited film. From the SAD patterns of TEM observation, a metastable C-Nd 2 O 3 phase was present in the Nd-rich phase of these films. In addition, it is known that the wettability of Nd-rich phase improves at temperatures around 550°C. Therefore, it is considered that the increase of coercivity is related to the improvement of fluidity of Nd-rich phase or the existence of C-Nd 2 O 3 phase.
影响因子：
3.2
作者：
Y. Shinba;T. Konno;K. Ishikawa;K. Hiraga;M. Sagawa
通讯作者：
Y. Shinba;T. Konno;K. Ishikawa;K. Hiraga;M. Sagawa