Incorporation of the Fe3O4 and SiO2 nanoparticles in epoxy-modified silicone resin as the coating for soft magnetic composites with enhanced performance

Highlights: • SiO₂ and/or Fe₃O₄ nanoparticles introduced to silicone resin as the coating of SMCs. • Morphology and composition of the hybrids revealed and correlated to the performance of SMCs. • Enhanced thermal, mechanical and magnetic properties achieved by addition of both SiO₂ and Fe₃O₄. • Function of the SiO₂ and Fe₃O₄ identified for improved performance of the SMCs. Three inorganic-organic hybrids have been designed by incorporating epoxy-modified silicone resin (ESR) with SiO₂, Fe₃O₄ and their mixture in the application as the coating of Fe soft magnetic composites (SMCs). The introduced SiO₂ nanoparticles are well dispersed in the ESR, while the Fe₃O₄ tends to agglomerate or even separate from the ESR. Simultaneous addition of the SiO₂ and Fe₃O₄ gives rise to satisfactory distribution of both nanoparticles and optimized magnetic performance of the SMCs with high permeability (124.6) and low loss (807.8 mW/cm³). On one hand, introduction of the ferromagnetic Fe₃O₄ reduces the magnetic dilution effect, which is beneficial for improved magnetization and permeability. On the other hand, SiO₂ incorporation prevents the agglomeration of the Fe₃O₄ nanoparticles and gives rise to increased electrical resistivity for reduced core loss as well as enhanced mechanical strength of the SMCs.