Analysis on the Causes of Defects in the Electrolytic Coloring Process on the Surface of Aluminum Profiles

At present, the application of a single anodized aluminum alloy building profile in practice has been significantly reduced, while the electrolytic colored oxide film, organic colored oxide film, porcelain oxide film, hard oxide film, and stainless steel imitation oxide film based on it are significantly reduced. It is widely used. Generally speaking, the factors that affect the coloring quality of oxide film are as follows:

(1) If the pre-treatment and degreasing process is not carried out thoroughly, it will cause obvious white spots on the film layer, which will bring difficulties to coloring.

(2) When the concentration of Sn salt in the electrolytic solution is too low, the coloring speed is slow. When the concentration is higher than 25 g/L, the coloring speed is fast, but it is not easy to grasp, and the color difference is often large. .

(3) The coloring temperature has a great influence on the coloring. When the temperature is lower than 15℃, the coloring speed is slow, and if the temperature is too high, the colored film will fog, and the Sn salt is easy to hydrolyze and react, causing the bath solution to become turbid.

(4) Time: The length of the coloring time will also affect the coloring quality and color resistance. For example, the coloring time is short, the color is light and easy to fade, the time is long, the color is too dark, and the surface is prone to blooming.

(5) When the coloring voltage is low, the coloring speed is slow, the color change is slow, and uneven tone is easy to occur. When the voltage is high, the coloring speed is fast and the colored film is easy to peel off.

(6) No matter in the anodic oxidation film formation or electrolytic coloring, additives and stabilizers based on surfactants must be added. The purpose is to stabilize the film formation speed and film thickness, inhibit the dissolution of the oxide film and improve the coloring Uniformity.