390 / 2022-03-15 19:01:56

Study on thermal conductivity and breakdown strength of core-shell Fe3O4@SiO2 enhanced epoxy composites

epoxy composites,thermal conductivity,core-shell structure,breakdown strength

Common epoxy composites have good electrical insulation performance, but the thermal conductivity still needs to be improved. In this paper, SiO2-coated Fe3O4 was added to the resin to study the influence of core-shell filler on the thermal conductivity of the resin, and the model of phonon conduction in the multilayer structure was established to improve the interface thermal resistance between filler and matrix.


Fe3O4 magnetic nanoparticles were prepared by co-precipitation method, then Fe3O4 particles were dispersed in ethanol, and silicon dioxide was coated on the magnetic nanoparticles by sol-gel method.  The prepared Fe3O4@SiO2 was added into the epoxy resin, and the composite sample was obtained after curing.  We use a laser thermal conductivity meter to test the thermal conductivity of the material and a ball-ball electrode were adopted to test the breakdown voltage.


When phonons move from Fe3O4 to epoxy matrix, the surrounding SiO2 acts as a bridge to reduce phonon loss at the interface, thus improving the overall thermal conductivity of the material. At the same time, the contact barrier formed by Fe3O4@SiO2 particles and epoxy matrix is smaller than that formed by simple Fe3O4 particles, which reduces the difficulty of charge transport at the interface and prevents charge from piling up at the interface between filler and matrix, reduces the electric field distortion at the interface, and improves the breakdown strength of the material.


In this paper, SiO2-coated Fe3O4 particles were prepared and added to epoxy resin to obtain epoxy composite material, which effectively improved the thermal conductivity and breakdown voltage of the material, and had a clearer understanding of the transmission mechanism of phonon and charge between epoxy matrix and inorganic filler. This core-shell structure of nanoparticles represents a promising method for reducing interfacial thermal resistance and can be extended to a variety of nanocomposite applications in the future.