Minor-Cu doped soft magnetic Fe-based FeCoBCSiCu amorphous alloys with high saturation magnetization

Yanhui Li,Wei Zhang,Zhenmin Wang

doi:10.1063/1.5006404

Abstract

The effects of Cu alloying on the amorphous-forming ability (AFA) and magnetic properties of the P-free Fe81Co5B11C2Si1 amorphous alloy were investigated. Addition of ≤ 1.0 at.% Cu enhances the AFA of the base alloy without significant deterioration of the soft magnetic properties. The Fe80.5Co5B11C2Si1Cu0.5 alloy with the largest critical thickness for amorphous formation of ∼35 μm possesses a high saturation magnetization (Bs) of ∼1.78 T, low coercivity of ∼14.6 A/m, and good bending ductility upon annealing in a wide temperature range of 513–553 K with maintaining the amorphous state. The fabrication of the new high-Fe-content Fe-Co-B-C-Si-Cu amorphous alloys by minor doping of Cu gives a guideline to developing high Bs amorphous alloys with excellent AFA.

Highlights

Soft magnetic Fe-based amorphous alloys play an attractive role for the energy saving due to their excellent magnetic softness and low core loss.[1,2] The typically Fe-B-Si amorphous alloys have been widely applied as core materials for distribution transformers.[3,4,5] the lower saturation magnetization (Bs) of ∼1.56 T compared with that of over 1.9 T for the Si-steels makes against the miniaturization of modern devices
The Bs was measured by a vibrating sample magnetometer (VSM) under a maximum applied field of 800 kA/m, and the Hc was obtained by a dc B-H loop tracer under a field up to 4000 A/m at room temperature
It has been generally accepted that the minor addition of elements having large negative ∆Hmix with the main constituents could enhance the glassforming ability (GFA)/amorphous-forming ability (AFA) and thermal stability against crystallization.[20]

Summary

INTRODUCTION

Soft magnetic Fe-based amorphous alloys play an attractive role for the energy saving due to their excellent magnetic softness and low core loss.[1,2] The typically Fe-B-Si amorphous alloys have been widely applied as core materials for distribution transformers.[3,4,5] the lower saturation magnetization (Bs) of ∼1.56 T compared with that of over 1.9 T for the Si-steels makes against the miniaturization of modern devices. Much effort has been paid to develop Fe-based amorphous alloys with high Bs. Increasing Fe content is a direct and effective way to enhance the Bs, whereas the amorphous-forming ability (AFA) is deteriorated greatly when the Fe content is ≥ 80 at.%.6. Alloying of appropriate Co is another way to increase the Bs due to the enhanced electron concentration contributing to the formation of magnetic moment.[7,8] The Fe68Co15B11C1P3Si29 and Fe68Co17B8P3Si410 amorphous alloys exhibit high Bs of ≥ 1.73 T. Subsequently alloyed by 0.25–1.0 at.% Cu. The results revealed that appropriate Cu enhances the AFA of the alloys without apparently reducing the soft magnetic properties

EXPERIMENTAL PROCEDURES

RESULTS AND DISCUSSION

CONCLUSION