Thermally induced structural evolution of diamond surface for pool boiling enhancement

Abstract

Effective thermal management in power devices is essential for energy-efficient operation. Pool boiling dissipates heat effectively through passive phase changes, eliminating the need for pumping power. However, these benefits remain unrealized in high-power-density devices owing to the risk of reaching Critical Heat Flux (CHF). The superior heat-spreading capabilities of diamond can help mitigate excessive heat flux in such devices. Consequently, pool boiling on diamond surfaces represents a promising cooling strategy for devices with high power densities. However, the inherent chemical inertness of diamond severely limits its surface modification, thereby posing significant challenges to the control of interfacial phenomena. This study investigated methods to modify Polycrystalline Diamond (PCD) surfaces to enhance their pool boiling performance. Thermal oxidation efficiently altered the PCD surface, exploiting its unique material properties. The enhanced surface enabled a 47.8% increase in the heat transfer coefficient and a 119.4% increase in the CHF. Additionally, an in-depth investigation clarified how structural and chemical modifications induced by high-temperature oxidation enhanced pool boiling performance.