HY Industry Corporation Limited

Analysis of the Defects of Electrolytic Shading Process on Aluminum Profile Surface

At present, the application of single anodized aluminum alloy building profiles has been significantly reduced in practice. In addition, it is widely used in electrolytic tinting oxide film, organic colored oxide film, ceramic oxide film, hard oxide film and imitation stainless steel oxide film. Generally speaking, the factors that affect the oxidation of aluminum profile are as follows:

1. Influence of impurities in electrolytic solution

(1) The copper ion will be deposited onto the surface of the aluminum, resulting in the release of the oxide film, and the ability to reduce the transparency, corrosion resistance and electrical insulation, therefore, the content of copper ions is not allowed to exceed 0.02 g/L.

(2) The chloride ion from the cooling water after the rupture of the tap water or the cooling pipe, the content of chloride ions should be less than 0.2 g/L, otherwise the oxide film produced is rough and loose, and the surface of the aluminum surface is etched (punctured).

(3) Aluminum ions in aluminum ion electrolyte are gradually increasing. When the content is greater than 25 g/L, the conductive property of the electrolyte decreases, the surface of the making part is white spot or block white spot, and the absorption capacity of the membrane layer is decreased and the dyeing is difficult.

(4) Iron ion content in iron ion electrolyte is not allowed to exceed 0.2 g/L, otherwise dark stripes will appear.

(5) Organic impurities can hinder the generation of oxide film, and the film adsorbs oil stains, causing uneven coloring and appearance of spots.

2. Factors affecting the color quality of the oxide film

(1) If the oil removal process about aluminum grating is not thoroughly treated before, it can cause obvious white spots on the film layer and make it difficult to color.

(2) When the Sn salt concentration in the electrolytic solution is too low, the upper color is slow. When the concentration is higher than 25 g/L, it is fast, but not easy to grasp, it often produces a large chromatic aberration.

(3) The coloring temperature has a great influence on coloring, if the temperature is below 15 ℃, the color is slow, if the temperature is too high, hair coloring film will fog, and prone to Sn salt hydrolysis reaction, which can make bath cloudy.

(4) Time: the length of pigmentation will also affect the color quality and color resistance. If the color time is short, the color is easy to fade, the time is long, the color is too deep, the surface is easy to hair flowers.

(5) When the color voltage is low, the color is slow, and the tone is not uniform. When the voltage is high, the dyeing speed is fast, and the coloring film is easy to flake off.

(6) Additives and stabilizers, which are mainly surfactant, are added in the anodized film or electrolytic coloring. The aim is to stabilize the film speed and film thickness, and inhibit the dissolution of the oxide film and improve the uniformity of coloring.

In addition, the pH value, water quality and pigmentation material have a certain influence on the color quality. The quality of the electrolytic tinted oxide film can be guaranteed only if the parameters are within the control range.