What is the Cause of Uneven Color of Aluminum Profile Oxide Film?

As a Modular Pipe System Manufacturer, share with you. Three possible causes of uneven color of aluminum oxide film:

Aluminum Profile

(1) The area is too large, the swing in the tank is too large during operation, and there is too large difference in the contact, renewal, and exchange of the edge and the center with the solution, resulting in inconsistent color of the oxide film. Prevention method: the amplitude of the workpiece swing should be small during oxidation, and static treatment is also possible, but when the temperature of the solution is too low, map-like spots are likely to appear, which is unnatural.

(2) During the processing of aluminum clad parts, part of the aluminum clad layer was damaged and cut off. The outer clad aluminum is high-quality aluminum, and the inner clad layer is heteroaluminum. "Vitiligo" like spots.

(3) Problems in process operation:

①The alkaline etching treatment is not complete, and the original oxide film and dirt in the local area cannot be removed;

②After alkaline etching, there is no light treatment immediately, the surface of the workpiece is still alkaline;

③The workpiece touched the foreign body during the transfer.

When there is uneven color of Aluminum Profile film layer, it is necessary to find the cause from various aspects and take targeted measures to solve it.

The failure caused by the excessive accumulation of aluminum ions in the alkaline etching solution, the reason why it is difficult to obtain a conductive oxide film after alkaline etching, after eliminating many factors that are difficult to form a conductive oxide film, consider whether there are too high aluminum ions in the alkaline etching solution Question, the other party said that the alkaline etching solution is very thick. But the alkali etching speed is not fast. It is recommended to replace the alkaline etching solution, because the alkaline etching solution will accumulate too much aluminum ions after a long time. The aluminum ions are difficult to elute on the surface of the workpiece, which affects the contact between the surface of the aluminum part and the conductive oxidizing solution, which affects the oxide film Formation. If the alkali etching solution is unconditionally replaced at that time, the alkali-etched workpiece can be rinsed in hot water immediately after rinsing in hot water, and then exposed to concentrated nitric acid containing hydrofluoric acid, and then subjected to conductive oxidation treatment after sufficient rinsing. The effect of washing with hot water after alkali etching is very good. After being scalded in hot water, leave the hot water quickly and immediately immerse in running water to prevent the formation of conductive oxide film due to oxidation after drying.

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