SiO2 nanoparticles enhanced silicone resin as the matrix for Fe soft magnetic composites with improved magnetic, mechanical and thermal properties

SiO2 nanoparticles have been introduced into epoxy-modified silicone resin (ESR) via two routes including direct addition (DA) and in-situ growth (ISG). Growth mechanism of the SiO2 nanoparticles has been revealed where chemical bonding forms between the SiO2 and the epoxy, ester and hydroxyl groups of the ESR during ISG. The obtained hybrid resins have been used as the matrix in the fabrication of Fe soft magnetic composites (SMCs). Effects of the SiO2 incorporation method and its content on the magnetic, electrical and mechanical properties of the SMCs have been investigated. Optimized performance of the SMC with large effective permeability (107.9), reduced core loss (1220 mW/cm3) and enhanced mechanical strength (2.95 MPa) can be achieved by introduction of 34 wt% SiO2 nanoparticles into the ESR via ISG. The formation of chemical bonding between the SiO2 nanoparticles and the ESR also gives rise to improved thermal stability for complete stress relaxation of the SMCs.