Influence of magnetic alignment and layered structure of BN&Fe/EP on thermal conducting performance

Abstract

A method to construct thermal conduction channels by orientational alignment of thermal particles in a magnetic field is proposed to increase the thermal conductivity of Epoxy Resin (EP) composite materials. Orientational thermal conducting layers were prepared using a BN–Fe–BN layered structure in a magnetic field, and then further overlapped to build the BN–Fe–BN layered samples with an orientational phonon thermal channel in the BN layer and electron thermal channels in the Fe layer. The SEM image shows the orientational alignment of thermal particles, which forms thermal conduction channels. Increased thermal conductivity of the layered structure was observed. When the BN&Fe filler weight concentration was 50%, thermal conductivity of the sample was 3.59 W m⁻¹ K⁻¹, 4.4 times that of the unaligned directly-mixed BN/Fe/EP sample (0.81 W m⁻¹ K⁻¹), and 17.8 times that of the pure EP (0.2 W m⁻¹ K⁻¹). The minimum resistivity of the sample was 6.52 × 10⁶ Ω cm in the frequency range 10⁻¹–10⁶ Hz. The dielectric constant and tan δ do not show obvious change as compared with pure EP when frequency is larger than 100 Hz.