Superhydrophobic double-layer coating for efficient heat dissipation and corrosion protection

To enhance the heat dissipation and anti-corrosion performance simultaneously, a superhydrophobic Al₂O₃/cerium hexadecanoate (Al₂O₃/CH) composite coating with high adhesion strength has been fabricated by plasma electrolytic oxidation and subsequent electrodeposition. The Al₂O₃/CH composite coating with a contact angle of 165.5° shows excellent water repelling and self-cleaning ability owing to the micro/nano structure and low surface energy. The composite coating enhances the corrosion potential of pure Al from −0.742 to −0.730 V and lowers the corrosion current density by two orders of magnitude. Thanks to the high emissivity in the wavelength range from 2.5 to 25 μm, the Al₂O₃/CH coated sample enables the operation temperature of a 5 W LED to drop approximately by 9.3 °C compared with Al substrate. In addition, the Al₂O₃/CH composite coating exhibits higher adhesion strength than that of the CH single layer. Therefore, the superhydrophobic coating is expected to be a promising candidate for heat dissipation and anti-corrosion applications.