Thermal conductive thin, flexible composite sheet of boron nitride aggregates and alumina for enhanced through plane conductivity

Abstract

In electronics sector, the trend of miniaturization will undoubtedly continue to drive forward with several technological advancements, however, there are some crucial issues especially in the thermal management of electronic devices that limits to what is pragmatically and economically feasible. For ensuring efficient thermal dissipation and preventing temperature overloads at local sites, in this work, an advanced thermal filler material (BN aggregate) synthesized via a cost effective and scalable route from h-BN (Hexagonal Boron Nitride) is proposed. To assess the suitability of the BN aggregate as a conventional ceramic filler material and its effectiveness for thermal management, a thermally conductive thin composite sheet is (200 μm) fabricated with the synthesized BN aggregates and spherical Al2O3. The thermal sheet made out of an optimized ratio between the Al2O3 and BN aggregate delivers an excellent through-plane (k⊥) and in-plane (k∥) thermal conductivity of 8.142 W/m.K and 5.601 W/m.K respectively. Even at higher filler concentration, this thin sheet which mimics a papery film, practically endured no deterioration in the mechanical integrity. This thermal sheet given its reasonable thermal and mechanical properties can be employed in electrical devices that demands high power cycles. With wearable technology gaining greater attention in the recent days, the proposed filler system when dispersed in polyethylene fibers, may find potential applications in thermoelectric devices, smart textiles, wearable displays and health monitoring systems.