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Common problems of aluminum anodizing

Release time:

2021-06-02 14:00

Q1: What is the reason why the anodic oxide film is gray?

High silicon aluminum alloy film is gray, when the silicon content of more than 5%, the film color will be dark gray. Although the film loses the milky white of pure aluminum, it has a unique decorative effect. Due to the different silicon content, the color depth of the oxide film will also be quite different, in order to match each other, still need to remember the material grade and finishing method.

Q2: How does the purity of the substrate affect the quality of the anodic oxide film?

For the quality of the anodic oxide film, the higher the purity of the substrate, the better the quality of the obtained film, regardless of the corrosion resistance or decoration of the film. Therefore, under possible conditions, the material should be as pure as possible. Of course, also take into account the strength of the material, which is probably the first condition for some parts;

Also consider the economic rationality, high purity materials are relatively more expensive than general industrial pure aluminum. The souvenirs such as chapters and badgles are made of high-quality aluminum, so they can shine with golden light after dyeing.

Q3: How does the anodic oxidation time affect the quality of the oxide film?

The total oxidation time of aluminum anodic oxidation varies due to different process formulations, and its control range is also relatively strict. The oxide film obtained by too short anodic oxidation time is whitish, and the thickness is obviously thin; the oxide film obtained by too long anodic oxidation time appears dark. The chromic acid anodization process is more stringent than other anodizing processes.

Q4: What is the reason why the oxide film is thin and white?

This phenomenon is more common, the main reasons are the following six points:

(1) insufficient anodic oxidation time. The anodizing time shall be determined in accordance with the process requirements.

(2) the current density of anodic oxidation is too small. There may be errors in the calculation. (3) The electrolyte temperature is too low. The temperature shall be increased to the required value of the process specification. (4) individual pieces of short circuit. Confusion occurs between current density and voltage.

Q5: How to remove unqualified dyed film?

The dyed film that does not meet the quality requirements can be removed and re-dyed, but in most cases, it is often difficult to meet the quality requirements after fading. Therefore, it is often used to remove the film layer in alkali etching solution and then re-anodize and re-dye.