What causes the uneven color of the aluminum oxide film? Specifically, there are three main issues:
(1) The workpiece area of the aluminum plate is too large, the swing in the groove is too large during operation, and the contact, renewal and exchange between the edge and the center part and the solution are too different, resulting in inconsistent color of the oxide film. Prevention method: When the aluminum plate is oxidized, the swing of the workpiece should be small, and static treatment is also possible, but when the temperature of the solution is too low, map-shaped spots are prone to appear, which is unnatural.
(2) When the aluminum-clad sheet is processed, part of the aluminum-clad layer is damaged and cut off. The outer layer of aluminum is high-quality aluminum, and the inner layer of the clad is miscellaneous aluminum. "Like spots. This phenomenon is often not understood by customers, and manufacturers should do more explanation work to explain the reason, so as not to cause misunderstandings.
(3) Problems in the operation of aluminum plate oxidation process
① The alkaline etching treatment of the workpiece is not thorough, and the original oxide film and dirt in the local area cannot be completely removed;
②The surface of the workpiece is still alkaline if the light-emitting treatment is not performed immediately after the alkali etching;
③ The workpiece has come into contact with foreign objects during the transfer process.
When the color of the film is not uniform, it is necessary to find the reasons from various aspects and take targeted measures to solve it.
I explained the basic principles that lead to the uneven color of the aluminum plate oxide film. I believe that the technical personnel of the aluminum plate manufacturer have a complete concept. As long as these three tricks are mastered, the problem of uneven color of the aluminum plate oxide film will be easily solved. Let us explain an example:
The failure is caused by excessive accumulation of aluminum ions in the alkaline etching solution. A technician from an aluminum plate manufacturer called to inquire about the reason why it is difficult to obtain a conductive oxide film after alkaline etching. Said the alkaline etchant is very thick. But alkaline etching is not fast. At that time, the author suggested to replace the alkaline etching solution, because the alkaline etching solution will accumulate too much aluminum ions after being used for a long time, and the aluminum ions are difficult to elute on the surface of the workpiece, thus affecting the contact between the surface of the aluminum parts and the conductive oxidizing solution, thereby affecting the Formation of oxide film. Another suggestion is that if the alkaline etching solution is replaced unconditionally at that time, the workpiece after alkaline etching can be rinsed in hot water immediately after being rinsed in running water, and then light is emitted in concentrated nitric acid containing hydrofluoric acid, and then conduct electricity after sufficient rinsing. Oxidation treatment. Later, the reader called and said that the effect of washing with hot water after alkaline etching is very good. The author's experience is that after washing in hot water, leave the hot water quickly and immediately immerse it in running water to prevent the workpiece from being oxidized after drying and affecting the formation of conductive oxide film.
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