Synthesis of boron nitride microrods with fish-scale-like structures for enhanced thermal conductivity of water

Abstract

Hexagonal boron nitride (h-BN) has triggered great interest in thermal management system because of its superb thermal conductivity, excellent chemical inertness and outstanding tribological behavior. However, the application of BN in water suffers from the poor dispersion stability. Herein, we develop a spray drying and pyrolysis route to directly fabricate porous BN microrods with fish-scale-like structures. BN microrods exhibit long-term dispersion stability in aqueous solution due to their high hydroxylation degrees. Although the viscosity of water was increased after adding BN microrods, the friction coefficient and wear scar diameter were reduced obviously. Moreover, thermal conductivity of BN/water fluid was improved from 0.589 to 1.117 W/m K when the content of BN was 0.1 vol%, which was higher than that of previous results. These results demonstrate that the fish-scale-like structured BN microrods have great potential and irreplaceable advantage in thermal and tribological management.