Facile synthesis of Fe-6.5wt%Si/SiO2 soft magnetic composites as an efficient soft magnetic composite material at medium and high frequencies

Fe-6.5wt%Si/SiO2 soft magnetic composites (SMCs) were successfully designed to reduce the core loss and improve the magnetic properties of Fe-6.5wt%Si alloy via the fluidized in-situ chemical vapor deposition method combined with the subsequent spark plasma sintering (SPS) process. Most conductive Fe-6.5wt%Si particles were firstly coated with SiO2 during chemical vapor deposition, and the highly compact and insulated Fe-6.5wt%Si/SiO2 SMCs were then obtained quickly by the spark plasma sintering. A 470 nm thick SiO2 insulating layer was found to exist uniformly and densely around Fe-6.5wt%Si particles in Fe-6.5wt%Si/SiO2 SMCs with the fluidized chemical vapor deposition (FCVD) process. It caused these SMCs to exhibit much higher electrical resistivity, lower core loss, and better frequency stability of permeability than those of raw Fe-6.5wt%Si compacts and Fe-6.5wt%Si/SiO2 SMCs with the conventional chemical vapor deposition (CVD) process. This new method provides a promising way to optimize the magnetic properties of soft magnetic composite materials, which can possess larger energy conversion efficiency for the electric-magnetic switching devices. (C) 2018 Elsevier B.V. All rights reserved.