Low-frequency microwave absorption and favorable thermal conductivity in epoxy-based composite endowed by boron nitride@cobalt ferrite heterostructure fillers

The rapid development of microelectronic devices and integrated circuits has sparked an urgent need for electronic packaging materials that muster both high thermal conductivity and excellent microwave absorption performance. To this end, a solvothermal-assisted strategy is adopted to in situ grow magnetic cobalt ferrite (CoFe2O4) nanoparticles on ball-milling modified boron nitride (m-BN) to obtain BN@CoFe2O4 nanocomposites. These heterostructured fillers are then composited with epoxy (EP) to prepare BN@CoFe2O4/EP (BCE) nanocomposites integrating low-frequency microwave absorption and thermal conduction function. Benefiting from good synergy between BN with high heat conductivity and CoFe2O4 with magnetic loss capability, when the mass fraction of BN@CoFe2O4 is 40 wt% while the mass ratio of BN to CoFe2O4 is 5:3, the as-obtained BCE composite delivers low-frequency microwave absorption performance with minimum reflection loss value of -30.99 dB at 3.36 GHz and thermal conductivity as high as 1.33 W m-1 K- 1 (565 % higher than pure EP). This composites that muster low-frequency microwave absorption and high thermal conductivity possess great application prospects in electronic packaging of advanced electronics in 5 G era.