Analysis of three reasons leading to uneven color of aluminum profile oxide film

Analysis of three reasons leading to the uneven color of aluminum profile oxide film:

(1) The area of the aluminum profile workpiece is too large, the swing in the groove is too large during operation, and the contact, update and exchange between the edge and the center part and the solution are too large, which leads to the color inconsistency of the oxide film. . Prevention method: aluminum profile oxidation workpiece swing amplitude should be small, static treatment can also be, but when the solution temperature is too low, it is easy to appear map spots, it is not natural.

(2) aluminum profile processing part of the aluminum layer is damaged, is cut off, the outer aluminum is high quality aluminum, the inner layer of the package is mixed aluminum, the two kinds of aluminum difference is large, so after oxidation, there is a "good Purpura wind" like spots. This phenomenon is often not understood by customers, manufacturers should do more to explain the work, explain the cause, so as not to cause misunderstanding.

(3) Oxidation process operation problems:

(1) The workpiece alkaline etching treatment is not complete, local original oxide film, dirt can not be removed;

② No immediate light treatment after alkali corrosion, the workpiece surface is still alkaline;

③ The workpiece has been in contact with foreign bodies in the process of transfer.

When the film layer color is not uniform, we should find the reasons from many aspects and take targeted measures to solve it.

A reader called to ask why it is difficult to obtain a conductive oxide film after alkali etching of the workpiece. After eliminating many factors that make it difficult to form a conductive oxide film, he said that the alkali etching solution was very thick considering whether there was too much aluminum ion in the alkali etching solution. But the alkali erosion rate is not fast. At that time, the author suggested replacing the alkali etching solution, because the alkali etching solution would accumulate too much aluminum ions after using for too long, and aluminum ions would be difficult to elute on the workpiece surface, which would affect the contact between the surface of the aluminum and the conductive oxidation solution, thus affecting the formation of the oxide film. Another suggestion is that if the alkali etching solution is replaced unconditionally at that time, the alkali etching workpiece can be rinsed in hot water immediately after rinsing in running water, and then in concentrated nitric acid containing hydrofluoric acid to produce light, and then fully rinsed after conducting oxidation treatment. After the reader called to say that after alkali corrosion with hot water washing effect is very good. The author's experience is that, after washing in hot water quickly leave the hot water and immediately immersed in water, to prevent the workpiece after drying due to oxidation and affect the formation of conductive oxide film.