Thermal interface materials of PDMS with h-BN fillers synthesized from ferroboron via SHS

Thermal interface materials (TIMs) are widely used to enhance heat transfer between heat-generating components of electronic devices and cooling radiators. The rapid miniaturization of electronic devices and the increase in their specific capacity have led to excessive heat loads, necessitating the development of TIMs based on dielectric powder fillers with high thermal conductivity. This paper presents an energy-efficient approach for synthesizing hexagonal boron nitride (h-BN) powder, used as a filler for thermal interface pads with a polydimethylsiloxane polymer matrix. The h-BN filler was produced through a two-step process: (1) self-propagating high-temperature synthesis of Fe-BN powder through the self-sustaining exothermic reaction of an affordable ferroboron powder with gaseous nitrogen, followed by (2) acid leaching of the synthesized powders to remove iron. The BN phase content in the resulting powder filler is 99.6 wt%. The pads demonstrated a thermal conductivity of up to 1.95 W m⁻¹K⁻¹ with a 40 wt% filler content and an average particle size of 40 μm, all while retaining adequate flexibility and elasticity.