xiehe model

What factors affect aluminum anodizing color

With the development of science and technology, people have higher and higher requirements for products. The application of single-color anodized aluminum materials in life has been significantly reduced, but electrolytic colored oxide films and hard oxide films have been widely used in our lives.

Do you also have a certain understanding of oxide film coloring technology? What factors will affect the color of aluminum anodization during the production process?

The following are the factors that affect the color of aluminum anodization

Impurities in the electrolyte aluminum anodizing color

The coloring quality mainly depends on the quality of the oxide film. Therefore, the impurities in the sulfuric acid oxidation solution have a great impact on the oxide film. It is very important for us to promptly remove copper, iron, aluminum and other metal ion impurities and maintain the normal use of the solution. Otherwise, the following effects will occur:

Copper ions

Copper ions will be displaced and deposited on the surface of the part, causing the release of oxide films, reducing transparency, corrosion resistance and electrical insulation properties.

Chloride

Chloride ions come from tap water or cooling water, so the chloride ion content is less than 0.2g/L to avoid rough and loose surface erosion.

Aluminum ions

The aluminum ions in the electrolyte gradually increase. But when the content is greater than 25g/L, the conductivity of the electrolyte decreases. And white spots will appear on the surface, making coloring difficult.

Iron ions

The iron ions in the electrolyte are not allowed to exceed 0.2g/L, otherwise black stripes will appear on the surface of the parts.

In addition, the following factors will also affect the coloring quality of the oxide film:

Remove oil stains

Before the parts are painted, oil stains need to be thoroughly removed to avoid obvious white spots on the film layer, which will cause difficulties in painting.

Coloring temperature

Coloring temperature also has a great influence on the coloring effect. For example, the normal coloring temperature is 15°C. When it is lower than 15°C, the coloring is slower. However, when the temperature is too high, a layer of mist will be generated on the surface of the oxide film, causing the tank to be turbid.

Coloring time

It will directly affect the quality and color resistance of aluminum alloy parts: the coloring time is short and the color is easy to fade; the longer the time, the darker the color and the surface is easily scratched.

Coloring voltage

When the coloring voltage is low, the coloring is slow and the color changes slowly, easily causing uneven tone.

When the coloring voltage is high, the coloring speed is fast and the coloring film is easy to peel off. Of course, water quality, PH value, and coloring materials will also have a certain impact on the coloring quality of aluminum alloy anodization. As a professional CNC machining manufacturer, Xiehe will be able to provide you and your customers with the best suggestions and machining processes for you to choose.