Novel approach to corrosion resistance and radiative cooling with biomimetic amorphous coatings

Abstract

To address the application challenges of high-power-density electronic devices in harsh conditions, it is crucial to develop electric insulation materials that possess both corrosion resistance and excellent radiative cooling performance. In this study, inspired by the wrinkle morphology of the Camponotus ant with thermoregulation, a biomimetic amorphous coating composed of a hemispherical array was fabricated on aluminum alloy using plasma electrolytic oxidation (PEO) technology. This biomimetic microstructure is obtained by controlling the content of hexagonal boron nitride (h-BN) nanoparticles in the electrolyte, where the increase in current density at a later stage allows the transition of the porous coating to the hemispherical array. The effects of functional group vibration and rotation in combination with the hemispherical structure afford the biomimetic coating a high emissivity of 0.91 within the range of 3–14 μm, which reduces the LED temperature by 17.1 °C and achieves a cooling efficiency of 10.6 %. Meanwhile, with a resistivity of 5.15 × 1014 Ω∙cm and a dielectric strength of 29.9 V/μm, the coating can prevent current leakage, consequently improving the stability and reliability of electronic packaging materials. In addition, h-BN flakes in the biomimetic coating with almost defects free act as a protective barrier to enhance the corrosion resistance of the aluminum alloy. This approach offers a time-efficient and cost-effective route for the manufacture of multifunctional coatings with potential applications in electronic packaging.