From the point of view of the need for colorless and transparent oxide film after oxidation, the 5 and 6 series aluminum alloys are better, and they can also be colored after oxidation. If only anodic oxidation is required to form a dense anodic oxide film, most Aluminium Profiles can be oxidized if there is no requirement for color. Before choosing the oxidation process, you should have some understanding of the aluminum or aluminum alloy material, because the quality of the material and the difference in the components will directly affect the quality of anodized aluminum products. For example, if there are defects such as bubbles, scratches, peeling, and roughness on the aluminum surface, all defects will still be exposed after anodizing. The alloy composition also directly affects the surface appearance after anodizing. The effects of copper, silicon, iron and other impurities on the surface the appearance of the oxide film in aluminum alloys are as follows: copper can make the oxide film reddish, damage the electrolyte quality and increase oxidation defects; silicon can make the oxide film gray, and the effect is more obvious; Due to its characteristics, iron will exist as black spots after anodizing.
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In addition, there are other impurities in the alloy that affect the appearance of the oxide film: 1-2% manganese aluminum alloy, brown blue after oxidation, with the increase of manganese content in the aluminum, the surface color after oxidation from brown blue converted to dark brown. Aluminum alloy containing 0.6-1.5% silicon is gray after oxidation, and white-grey when silicon is 6% -6%. Zinc-containing is opacified, chromium-containing is uneven to golden to gray, and nickel-containing is pale yellow. Generally speaking, only aluminum-containing magnesium-containing magnesium and titanium-containing more than 5% containing gold can obtain a colorless, transparent, bright, and smooth appearance after oxidation.
As a Modular Pipe System Manufacturer, it should be noted that some aluminum profiles are made in different colors. These colors are not oxidized but are formed by anodizing aluminum after being anodized, dyed or electrolytically colored. Dyeing basically has all colors, but electrolytic coloring is less, you can do it, black, bronze, champagne, golden yellow, imitation stainless steel.
The most common harmful impurity in aluminum is iron. In the production process of aluminum profiles for the construction industry, when the iron content is greater than 0.25%, a very normal hue is not obtained. As the iron content increases, the gloss decreases and the hue is uneven. Green, grayish gray is ugly. When the content of silicon in gold is low, the effect of iron is more obvious. When the silicon is high, the harmful effects of iron can be reduced to a certain extent. At this time, iron and silicon form AlFeSi intermetallic compounds, and some of them are also consumed. Excess silicon. The main reason that iron affects coloring is that iron and aluminum form a pointed or rod-like structure, ranging from a few microns to tens of microns. Its electrode potential is different from aluminum, so it affects the uniformity and continuity of oxidation coloring, and also makes the oxide film gloss. And the transparency is reduced, affecting the coloring effect.
A small amount of copper is beneficial to the mechanical properties and surface brightness of the aluminum profile without reducing the corrosion resistance. However, when the copper content is large, the oxide film becomes black, which can be seen by the naked eye. Our company also has Modular Pipe System on sale, welcome to consult.
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