Structural coloring of aluminum

A porous anodic aluminum oxide film with a regular periodic variation of pore density normal to the surface is created by alternating the current density in current-controlled anodization. Regularity of the effective refractive index is achieved by altering the current pulse time to compensate for the etching of the layers in the electrolyte as anodization proceeds. The resulting photonic crystals display brilliant interference colors in reflected white light. These structural colors can be adjusted throughout the visible light region simply by altering the current pulse time. The method can be applied both to aluminum and its alloys.

By employing a current-controlled anodization method and a layer spacing compensatory strategy, structural coloring of aluminum has been realized successfully without any physical and chemical post-treatment after anodization.Figure optionsDownload as PowerPoint slideHighlights
► Structural coloring of aluminum is realized by an anodization method and a compensatory strategy.
► The colors are shown vividly without any physical and chemical post-treatment after anodization.
► The structural colors can be adjusted easily in visible light region.
► This technique is simultaneously suitable for aluminum and its alloys.