Unit-Cell Design of Metallic Heat Radiation Device by Micro- and Nano-Texturing

A metallic sheet radiation device was keenly required for cooling the solar panel and giant antenna in space. Micro- and nano-texturing to metallic sheet surfaces, provided a way to significantly improve the infra-red (IR) emission property from optical insulation of polished metal sheets. Unit cell shape and alignment in this texturing has much influence on the IR-emissivity and the working wavelength range. A simplified theoretical model was proposed to design the micro-cone shaped unit cell. Two-step procedure was utilized to form the micro-cone textures into the copper sheet via the laser micro-machining and to build up the nickel nanotextures onto the micro-textured surface and copper clearance via the electroplating. IR-emission spectroscopy was used to demonstrate that micro-cone shaped microtextures enhanced the IR-emissivity and that nano-textures worked as a helper to further increase the IR-emissivity.