Functional composites with core–shell fillers: I. Particle synthesis and thermal conductivity measurements

Filled epoxy composites are broadly used in electronic and power devices as an electrical insulation. It is of importance to achieve efficient heat dissipation in such devices due to fact that thermal properties have a strong influence on their proper operation. For this reason, the modification of standard filler materials, such as silica or alumina, can give a promising solution. In this work, a novel core–shell material has been proposed and manufactured by means of a carbothermal reduction and nitridation process. The obtained fillers are made of a standard material which is covered by the high thermally conductive shell. The synthesized fillers were characterized by means of X-ray diffraction, and scanning electron microscopy coupled with elemental analysis. The composite samples based on epoxy resin filled with the manufactured core–shell fillers have been investigated in order to determine their effective thermal conductivity. The obtained composite samples exhibited a significant improvement in the thermal conductivity, represented by a 63 % relative increase. The obtained results show the potential for the novel core–shell fillers to be applied for the electrical insulation with the enhanced thermal conductivity.