Fe-based amorphous soft magnetic alloys with high saturation magnetization and good bending ductility

doi:10.1016/j.jallcom.2014.06.093

Journal of Alloys and Compounds

Volume 615, 5 December 2014, Pages 163-166

https://doi.org/10.1016/j.jallcom.2014.06.093 Get rights and content

Highlights

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Fe-B-Si-P amorphous alloys with high B_s up to 1.7 T were synthesized.
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The amorphous alloys exhibit low H_c of 3.3–6.2 A/m and high μ_e of 8300 to 15000.
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The present alloys show good bending ductility, even in an annealed state.

Abstract

Fe-based amorphous alloys with high saturation magnetization up to 1.7 T were synthesized in Fe–B–Si–P alloy system. The amorphous alloys exhibit good soft magnetic properties, such as low coercive force of 3.3–6.2 A/m and high effective permeability of 8300–15,000. In additional, the present alloys show good bending ductility, even in an annealed state. The combination of good magnetic and mechanical properties makes them promising candidates as magnetic functional materials in the future.

Introduction

Magnetic materials play an increasingly important role in modern industry as an essential part of electric motors, electric propulsion, actuators, sensors and data storage devices. Fe-metalloid amorphous alloys were found to exhibit superior soft magnetic properties (such as lower coercivity, higher permeability and lower core loss) [1], [2]. The good soft magnetic properties are due to the absence of crystal magnetic anisotropy and grain boundaries in amorphous phase. The development of Fe-based soft magnetic amorphous alloys with unique structure, good mechanical properties and superior magnetic properties has attracted much attention in a variety of emerging science and engineering technology [3], [4], [5].

Over the past several decades, a large number of studies on amorphous soft magnetic alloys have been carried out and various types of Fe-based amorphous alloys have been developed [6], [7], [8], [9], [10]. It is known that Fe–Si–B amorphous alloys have been widely used as magnetic cores in devices requiring low core loss and high permeability, such as distribution and power transformers, motors and high frequency inductors, due to the combination of high saturation magnetization, high permeability and low core loss. For instance, Fe–Si–B amorphous alloy with trademark of Metglas® 2605SA1 shows high saturation magnetization of 1.56 T, high permeability and extremely low core loss (40% of the core loss of grade M3 Si steel) [11]. In addition to Fe–B–Si system, Fe-based amorphous alloys have been synthesized in various alloy systems such as Fe–B–C [12], Fe–B–P [13], Fe–Si–C [14] and Fe–Si–B–C [15] systems, with the aim of developing good soft magnetic amorphous materials. However, little is known about magnetic and mechanical properties of Fe-rich Fe–B–P–Si amorphous alloys containing Fe contents above 82 at.%, though glass-type alloys with distinct glass transition and rather wide supercooled liquid region have been synthesized in ribbon [16] and bulk [17], [18] forms in a Fe content range below 80 at.% by our group. The glass-forming ability in Fe–B–P–Si systems is high enough to form bulk glassy alloys with diameters up to 2.5 mm [19]. This quaternary alloy system is believed to be only an alloy system in which bulk glassy alloys can be formed without the addition of any transition metals except Fe by copper mold casting. Consequently, the development of a new soft magnetic amorphous alloy by utilizing the advantage of high glass-forming ability in this alloy system is significant for future progress in nonequilibrium soft magnetic material field.

Recently, there has been an increasing emphasis on the development of modern power electronics with excellent performance, high reliability, small in size and light in weight. It has been required to prepare soft magnetic materials with higher B_s, combined with good soft magnetic properties, high stability and low cost [20], [21]. However, amorphous alloys developed to date show much lower saturation magnetization compared with Si steel or Fe-rich nanocrystalline alloys [22], [23]. In addition, Fe-based amorphous alloys, almost inevitably, become brittle in the process of structural relaxation, which makes them difficult to handle and limits their industrial and commercial applications. At present, when improving energy efficiency and energy conservation becomes a global issue, there has been a strong demand on the development of Fe-based soft magnetic amorphous alloys with high saturation magnetization and good mechanical properties. This paper aims to synthesize Fe-based amorphous alloys with high saturation magnetization above 1.65 T in Fe–B–Si–P alloy system and clarify their magnetic softness and mechanical properties.

Section snippets

Experimental procedures

Alloy ingots of Fe–B–Si–P with nominal atomic composition of Fe₈₁B₁₀Si_5.5P_3.5, Fe₈₂B₁₀Si₅P₃, Fe₈₃B₉Si₅P₃, Fe₈₄B_8.5Si_4.5P₃ and Fe₈₅B₈Si₄P₃ were prepared by induction melting high-purity Fe, Si, B elements and prealloyed Fe₃P alloy. The as-quenched ribbons were prepared by a single roller melt-spinning technique in an argon atmosphere. Molten alloys are ejected from the small hole at the bottom of quartz tube onto a rapidly rotating copper wheel with an argon pressure difference of 0.02 MPa. The

Results and discussion

The amorphous nature of samples both in the as-prepared and the annealed states (after structural relaxation) has been confirmed by X-ray diffraction technique. As examples, the XRD patterns of the ribbons after structural relaxation are shown in Fig. 1. Only broad peaks without appreciable crystalline peaks can be observed, which are characteristic of an amorphous structure. These results indicate that amorphous ribbons with high Fe contents up to 85 at.% are formed in Fe–B–Si–P alloy system.

Conclusions

We examined the formation, thermals stability, magnetic characteristics and mechanical properties of Fe–B–Si–P amorphous alloys with high Fe contents from 81 at.% to 85 at.%. The alloys show high saturation magnetization up to 1.70 T, good magnetic softness, high hardness values and good bending ductility even in the annealed state where the optimum magnetic softness is obtained. Moreover, the raw materials of the alloys are low-cost and high-productivity. Therefore, the Fe–B–Si–P amorphous alloys

Acknowledgments

This research study was funded by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Uner Grat no. (53-3-1433/HiCi). The authors, therefore, acknowledge with thanks DSR technical and financial support.

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Fe-based amorphous soft magnetic alloys with high saturation magnetization and good bending ductility

Highlights

Abstract

Introduction

Section snippets

Experimental procedures

Results and discussion

Conclusions

Acknowledgments

Acta Mater.

Prog. Mater Sci.

J. Magn. Magn. Mater.

J. Non-Cryst. Solids

Mater. Sci. Eng., B