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

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.