Radiation-Enhanced Heat Pipe Radiator via Surface-Engineered Hierarchical Resin-Free Coating for Effective Passive Heat Dissipation of High-Power Electronic Modules

Effective heat dissipation is critical for high-power modules amid increasing demands for compact, lightweight, and high-performance electronic devices. This study presents a passive cooling strategy employing a type of hierarchical resin-free coating (HRC) on the etched surfaces of a heat pipe radiator for cooling high-power modules. The HRC consists of graphene-hybridized hexagonal boron nitride (h-BN) nanosheet networks fabricated via a scalable three-step chemical etching on substrate, ball-milling exfoliation, and silane coupling process. It achieves an infrared emissivity of 0.97, owing to strong phonon vibrations within 2D nanosheets and localized surface plasmon resonance from hierarchical micro/nanostructures which induce electromagnetic field polarization, as confirmed by numerical simulation. Heat dissipation performance of a heat pipe radiator coated with the HRC, as compared to the uncoated one, is apparently improved due to the enhanced radiative cooling. Experimental and numerical results demonstrate that the radiator with coatings, relative to the uncoated one, yields a 3.1–9.9 °C temperature reduction at air velocities of 1–5 m s⁻¹ and a decrease of total thermal resistance by up to 16.7% under 1.5 kW heat load. This work provides a new design concept for environmentally friendly, highly efficient, and sustainable thermal management solutions in high-power electronic modules.