Chemical composition and coercivity of SmCo5 magnets

被引:45
作者
de Campos, MF
Landgraf, FJG
Saito, NH
Romero, SA
Neiva, AC
Missell, FP
de Morais, E
Gama, S
Obrucheva, EV
Jalnin, BV
机构
[1] Univ Sao Paulo, Escola Politecn, Dept Met & Mat, BR-05508900 Sao Paulo, Brazil
[2] Inst Pesquisas Technol, BR-05508901 Sao Paulo, Brazil
[3] Univ Sao Paulo, Inst Fis, BR-05315970 Sao Paulo, Brazil
[4] UNICAMP, Inst Fis Gleb Watagin, BR-13083970 Campinas, SP, Brazil
[5] Moscow Steel & Alloys Inst, Moscow 117936, Russia
关键词
D O I
10.1063/1.368075
中图分类号
O59 [应用物理学];
学科分类号
摘要
The effects of alloy composition and heat treatment on the intrinsic coercivity H-i(c) of SmCo5 magnets were studied. Alloys having six chemical compositions near that of stoichiometric SmCo5 were used to produce magnets via the usual powder metallurgy techniques. Magnets were either as sintered (1150 degrees C) or sintered (1150 degrees C) and treated at 850 degrees C. The substantial increase in H-i(c) due to the 850 degrees C heat treatment occurs reversibly and with a negligible change in lattice parameters Curie temperature T-c and anisotropy held H-A. Quantitative metallography and thermomagnetic measurements showed that the microstructural constituent present in addition to the SmCo5 phase in hyperstoichiometric alloys is composed of both the Sm2Co7 phase and the Sm5Co19 phase. Measurements of magnetization in de magnetic fields up to 33 T suggest that H-A is around 53 T, considerably higher than previously reported values. The coercivity of the magnets is discussed in terms of thermal equilibrium populations of lattice defects. (C) 1998 American Institute of Physics.
引用
收藏
页码:368 / 373
页数:6
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