Mechanically strong nanocrystalline Fe-Si-B-P-Cu soft magnetic powder cores utilizing magnetic metallic glass as a binder

Jian Luan,Akihiro Makino,Yan Zhang,Parmanand Sharma,Noriharu Yodoshi

doi:10.1063/1.4944766

Jian Luan, Akihiro Makino + Show 3 more

Open Access

https://doi.org/10.1063/1.4944766

Copy DOI

Abstract

We report on the fabrication and properties of soft magnetic powder cores with superior mechanical strength as well as low core loss (W). Development of such cores is important for applications in automobiles/devices operating in motion. High saturation magnetic flux density (Bs) Fe-Si-B-P-Cu powder was sintered with Fe55C10B5P10Ni15Mo5 metallic glass (MG) powder in its supercooled liquid state by spark plasma sintering. The sintered cores are made from the nanocrystalline powder particles of Fe-Si-B-P-Cu alloy, which are separated through a magnetic Fe55C10B5P10Ni15Mo5 MG alloy. Low W of ∼ 2.2 W/kg (at 1T and 50 Hz), and high fracture strength (yielding stress ∼500 MPa), which is an order of magnitude higher than the conventional powder cores, were obtained. Stronger metal-metal bonding and magnetic nature of MG binder (which is very different than the conventional polymer based binders) are responsible for the superior mechanical and magnetic properties. The MG binder not only helps in improving the mechanical properties but it also enhances the overall Bs of the core.

Highlights

Powder cores can be made into desired shapes and sizes with the ability to guide magnetic flux uniformly in three dimensions.[1,2] For applications in low to medium frequency range, powder cores suffer with high core loss (W ).[3,4,5,6,7,8] This is due to enhanced hysteresis loss resulting from non-magnetic polymer resin between the powder particles in a core
We report on the fabrication and properties of soft magnetic powder cores with superior mechanical strength as well as low core loss (W )
The sintered cores are made from the nanocrystalline powder particles of Fe-Si-B-P-Cu alloy, which are separated through a magnetic Fe55C10B5P10Ni15Mo5 metallic glass (MG) alloy

Summary

INTRODUCTION

Powder cores can be made into desired shapes and sizes with the ability to guide magnetic flux uniformly in three dimensions.[1,2] For applications in low to medium frequency range, powder cores suffer with high core loss (W ).[3,4,5,6,7,8] This is due to enhanced hysteresis loss (total loss ∼ hysteresis + eddy current loss) resulting from non-magnetic polymer resin between the powder particles in a core. Can significantly reduce the Bs, and increase the coercivity/core loss by acting as pinning cites for domain wall motion.[15] Best magnetic cores can be powder cores with magnetic properties similar to stacked cores To realize such a core, non-magnetic binder should be replaced with a magnetic one, and magnetic powder particle should have low anisotropy, preferably exhibit nanocrystalline structure. The major difference in microstructure between nanocrystalline alloy and the one we are planning to make will be the Fe grains replaced by the powder particles i.e. the micron size nanocrystalline magnetic powder particles in a magnetic amorphous matrix This kind of microstructure of a sintered core can ensure the excellent magnetic properties along with good mechanical strength. We believe that with this idea, it is possible to increase the overall Bs of powder cores if a MG binder with high Bs can be utilized

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSIONS