scholarly journals Fe-Si/MnZn(Fe2O4)2 Core-shell Composites with Excellent Magnetic Properties by Mechanical Milling and Spark Plasma Sintering (SPS)

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 553 ◽  
Author(s):  
Liang Yan ◽  
Biao Yan

The Fe-Si/MnZn(Fe2O4)2 composite powders are synthetized by means of the mechanical milling, and Fe-Si/MnZn(Fe2O4)2 soft magnetic composites are prepared by spark plasma sintering (SPS). The impact of milling time on particle size, phase structure and magnetic properties of the investigative core-shell structure powders along with that of sintering temperature on microstructure and magnetic properties of FeSi-MnZn(Fe2O4)2 soft magnetic composite are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). The experimental results demonstrate a layer of MnZn(Fe2O4)2 forming a coating on the surface of Fe-Si powder after mechanical milling, and the soft magnetic composites exhibiting excellent magnetic performance at 900 °C: 212.49 emu/g for saturation magnetization, with 6.89 Oe for coercivity, 3 × 10−4 Ω.m for electrical resistivity and stable amplitude permeability and low core loss over a wide frequency range. Therefore, SPS offers a convenient and swift way to enhance performance of soft magnetic composites using magnetic materials as insulting layer.

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744013 ◽  
Author(s):  
Liang Yan ◽  
Biao Yan

Fe–6.5 wt.% Si powder coated with 10 wt.% MnZn(Fe2O4)2 (MnZn ferrite) was successfully prepared by using dry-type stirring ball milling. The Fe–6.5 wt.% Si/MnZn(Fe2O4)2 soft magnetic composites were prepared by subsequent spark plasma sintering. This paper aims at analyzing the microstructure and magnetic properties of Fe–6.5 wt.% Si/MnZn(Fe2O4)2 soft magnetic composites (sintering temperature: 750[Formula: see text]C, sintering pressure: 50 MPa, holding time: 8 min, heating rate: 60 K/min). Based on X-ray diffraction and scanning electron microscopy, microstructure and powder morphology were examined and magnetic measurements on bulk samples were conducted by vibrating sample magnetometer and impedance analyzer. According to the experiments results, Fe–6.5 wt.% Si/MnZn(Fe2O4)2 composites displayed a core-shell structure, and ceramic phase was observed after sintering. The Fe–6.5 wt.% Si/MnZn(Fe2O4)2 composites achieved high resistivity ([Formula: see text] m[Formula: see text]/cm) while maintaining excellent magnetic properties ([Formula: see text] emu/g). Core losses especially at medium and high frequencies were significantly reduced.


2017 ◽  
Vol 898 ◽  
pp. 684-688
Author(s):  
Ji Hang Ren ◽  
Zhan Kui Zhao

Iron-based amorphous alloys have attracted technological and scientific interests due to their excellent soft magnetic properties. In the present study, Ni0.5Zn0.5Fe2O4/Fe76Si9B10P5 soft magnetic composites cylinder of 15 mm diameter and 3 mm thickness was prepared by spark plasma sintering at the temperature of 780 K. The amorphous Fe-based soft magnetic composites Ni0.5Zn0.5Fe2O4/Fe76Si9B10P5 exhibited good magnetic properties after annealing treatment at temperature ranging from 643 K to 743 K. The beneficial effects of treatment under different temperatures were discussed in terms of the improved magnetic performance of Ni0.5Zn0.5Fe2O4/Fe76Si9B10P5 soft magnetic composites.


2009 ◽  
Vol 17 (4) ◽  
pp. 218-221 ◽  
Author(s):  
Sangmin Lee ◽  
Hidemi Kato ◽  
Takeshi Kubota ◽  
Akihiro Makino ◽  
Akihisa Inoue

2004 ◽  
Vol 19 (9) ◽  
pp. 2730-2737 ◽  
Author(s):  
Tetsuji Saito ◽  
Tomonari Takeuchi ◽  
Hiroyuki Kageyama

We studied the effects of the sintering temperature and applied pressure on Nd–Fe–B bulk nanocomposite magnets produced by the spark plasma sintering (SPS) method. Amorphous Nd4Fe77.5B18.5 melt-spun ribbons were successfully consolidated into bulk form by the SPS method. When sintered at 873 K under applied pressures between 30 and 70 MPa, the bulk materials consisted of nanocomposite materials with a soft magnetic Fe3B phase and hard magnetic Nd2Fe14B phase. The density and magnetic properties of the bulk materials sintered at 873 K were strongly dependent on the applied pressure during sintering. Bulk Nd4Fe77.5B18.5 nanocomposite magnets sintered at 873 K under an applied pressure of 70 MPa showed a high remanence of 9.3 kG with a high coercivity of 2.5 kOe.


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