Effect of micro-nano particles on thermal conductivity and high-frequency insulation properties of epoxy composites

In present study, the epoxy resin (EP) samples co-doped with micron hexagonal boron nitride (h-BN) and nanoparticles including Al
2
O
3
, SiO
2
, and AIN were prepared by casting in the lab. The thermal conductivity, dielectric loss and breakdown strength of the co-doped epoxy resin samples were systematically investigated at different frequencies. Compared with pure EP, co-doped samples exhibited better thermal conductivity and higher breakdown strength. The optimum performance took placed in the EP samples co-doped with h-BN and Al
2
O
3
. The thermal conductivity and breakdown strength could reach 0.384 W/(m-K) and 110.8 kV/mm at 20 kHz, enhanced by 78.6% and 54.49%, respectively. All the results indicated that thermal conductivity and high frequency insulation properties could be improved significantly by micro-and nano-co-doping, rendering EP become attracted in the application of high frequency power transformers.