This is a "one-time coloring" process, some specific components of aluminum alloy in the process of aluminum anodic oxidation, to the state of metal or oxide dispersion in the anodic oxidation film, so as to get the color of the oxide film.

Perhaps the most famous example of alloy hair color is 4043 aluminum alloy containing approximately 5% Si, which appears gray after anodizing with sulfuric acid due to the dispersion of fine Si particles in the anodized film. This process is used in the production of aluminium alloy sheets for construction.

The development of various components of aluminum alloy to obtain the effect of natural color, this process route is difficult to achieve the uniformity of color, special preparation of aluminum alloy cost is higher, rarely used in practice.

This is another "one-time coloring" process, generally with organic acid anodizing treatment, different organic acid components mixed with anodizing film can get different colors, so different organic acid selection and different operating conditions will determine the color of the formation.

In general, this method uses a relatively high anodizing voltage for aluminum, perhaps three times that for ordinary sulfuric acid anodizing. This consumes a lot of electricity, which hampers the popularity of the process. But electrolytic hair color and alloy hair color, the film weather resistance is good, but the operation cost is high.