Sintering densification of thermally degradable magnetic powders and characterization of their grain boundaries

被引：0

作者：

Takagi, Kenta ^{[1
]}

Nakayama, Hiroyuki ^{[1
]}

Ozaki, Kimihiro ^{[1
]}

机构：

[1] National Institute of Advanced Industrial and Technology (AIST), 2266-98 Anagahora Shimoshidami, Moriyama-ku, Nagoya

来源：

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | 2014年 / 61卷 / 04期

关键词：

Coercivity; Low-twmperature sintering; Permanent magnets; Sm-Fe-N; Thermal decomposition;

D O I：

10.2497/jjspm.61.165

中图分类号：

学科分类号：

摘要：

This paper reviews our study of developing a sintering technique of thermally degradable Sm-Fe-N powders. The Sm-Fe-N coarse powder in the flake form was sintered using a low-thermal-load process of high pressure current sintering. By using cyclic compaction and optimum sintering temperature, this process produced dense isotropic bulk magnets without thermal decomposition that exhibited the high maximum energy product of 17.1 MGOe. Meanwhile, the Sm-Fe-N fine powder was also sintered by the same sintering technique. The coercivity of the sintered compacts considerably decreased regardless of sintering temperatures under the thermal decomposition temperature. TEM and XPS analyses on the grain boundaries led to estimation of the mechanism of coercivity decrease: the oxidation-reduction reaction between the initial iron oxides and the primary Sm-Fe-N phase generated a-Fe phases which might act as reverse magnetic domain nucleation sites.

引用

页码：165 / 170

页数：5