6. Extreme Two-Phase Cooling

This paper reports the first integration of laser-etched polycrystalline diamond microchannels with template-fabricated microporous copper for extreme convective boiling in a composite heat sink for power electronics and energy conversion. Diamond offers the highest thermal conductivity near room temperature, and enables aggressive heat spreading along triangular channel walls with 1:1 aspect ratio. Conformally coated porous copper with thickness 25 µm and 5 µm pore size optimizes fluid and heat transport for convective boiling within the diamond channels. Data reported here include 1280 W cm−2 of heat removal from 0.7 cm2 surface area with temperature rise beyond fluid saturation less than 21 K, corresponding to 6.3 × 105 W m−2 K−1 . This heat sink has the potential to dissipate much larger localized heat loads with small temperature nonuniformity (5 kW cm−2 over 200 µm × 200 µm with


Palko, J. W., Lee, H., Zhang, C., Dusseault, T. J., Maitra, T., Won, Y., … & Wilbur, J. D. (2017). Extreme Two‐Phase Cooling from Laser‐Etched Diamond and Conformal, Template‐Fabricated Microporous Copper. Advanced Functional Materials.