Synthesis of size-controlled and in-situ OH functionalized hexagonal boron nitride powder by hetero-phase reaction

Abstract

Hexagonal boron nitride (h-BN) is one of the most attracting insulating ceramics for the application as thermal interface materials (TIM) because it possesses high thermal conductivity coupled with electrical insulation property. Although the uniform size control of h-BN is a crucial factor in quality control of the TIM, the synthetic technology of h-BN with uniform and narrow size distribution has been limited, and the typical scale-up process necessitates high-temperature reaction involving the use of toxic vapor reactants of boron and nitrogen sources. In this research, we present a simple fabrication process for single-step massive production of size controlled in-situ hydroxyl group functionalized h-BN powder. The main idea behind the synthesis of h-BN powder lies in the application of liquid-vapor phased reactants coupled with calcination at reduced temperature, rather than other typical synthetic processes of h-BN in a semi-closed system. Analysis showed that the lateral size of h-BN is controlled between 20 and 225 nm with a narrow distribution. The h-BN powder forms hydroxyl groups via in-situ synthesis.