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Why does anodized aluminum become easier to colour?
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Anodized aluminum becomes easier to color because the anodizing process creates a unique, nanostructured surface layer known as anodic aluminum oxide (AAO). This layer is characterized by a highly porous structure consisting of cylindrical pores.1
These pores are the key to the material's receptivity to color. During the oxidation process, dyes can be introduced into the electrolyte bath, allowing the pigment to penetrate and be absorbed into the porous structure of the oxide film. The ability to tailor the size and thickness of these pores allows for precise control over the coloring process, making it an effective method for decorative finishing in various industrial and architectural applications.21