Effect of sintering temperature on microstructure and magnetic properties for Fe-Si soft magnetic composites prepared by water oxidation combined with spark plasma sintering

Abstract Fe-Si SMCs with different insulating layer (Fe 2 SiO 4 /SiO 2 ) have been prepared successfully via sintering the oxidized Fe-Si powders at different temperature. We have investigated the effect of sintering temperature on microstructure and magnetic properties for the Fe-Si SMCs in detail. The insulating layer is mainly Fe 2 SiO 4 when the sintering temperature is 800 °C and 900 °C. Noting that a three-shell insulating layer composed of Fe 2 SiO 4 and SiO 2 is formed when the sintering temperature reaches 1000 °C. However, excessive sintering temperature including 1100 °C and 1200 °C, will result in the generation of SiO 2 and many Fe atoms. Thus, the core loss and quality factor increase with increasing the sintering temperature from 800 °C to 1200 °C except for 1000 °C due to the unique three-shell insulating layer, while the saturation magnetization increases gradually. And optimized magnetic properties including very low core loss of 169.7 mW/cm 3 , Ms of 183.6 emu/g, μ e of 59 and Q of 6.9 have been obtained for the Fe-Si SMCs sintered at 1000 °C.