High‐thermal‐conduction and low‐cost composite originated from the tight packing structure of boron nitride sheets and binary alumina balls

In this work, a novel low‐cost and thermal conductive composite consisting of boron nitride (BN)/aluminum oxide (Al2O3) heat transfer network was constructed by the high packing volume fraction of two sizes Al2O3 spheres at the optimal weight ratio. The dense packing of 5 μm Al2O3 and 20 μm Al2O3 supports the BN sheets scattering around Al2O3 to interconnect into main three‐dimensional BN network, and acts as thermal conductive bridges forming secondary BN‐Al2O3 heat transfer networks. The maximum thermal conductivity of the composite reached 3.61 Wm−1 K−1, which was 20.1 times more than that of pure epoxy resin. Moreover, the excellent capacity of heat dissipation and the dielectric properties denoted that the composite can be used commendably in electronic components. This article is expected to provide a novel idea for the preparation of economical and high‐performance thermal conductive composites applied in new generation of microelectronic devices.