The classification of aluminum oxidation of die castings: mainly aluminum oxidation, hard oxidation, casting oxidation, aluminum anodization, electrolytic coloring, dye coloring, various surface conductive oxidations, etc. The details are as follows: Aluminum anodizing mainly includes: natural color oxidation, color oxidation, natural acid sand surface oxidation, natural color alkaline sand surface oxidation.
Uses of aluminum oxide for :
1. Among the main component bauxite of aluminum ore, alumina has the highest content. Industrially, bauxite is purified into alumina by the Bayer process, and then converted into aluminum metal by the Hall-Heroult process.
2. Alumina is the reason why metal aluminum is not easily corroded in the air. Pure metallic aluminum easily reacts with oxygen in the air to form a thin aluminum oxide film covering the surface of aluminum exposed to the air. This aluminum oxide film can prevent aluminum from being oxidized further. The thickness and properties of this oxide film can be enhanced by a process called anodic treatment (anodic corrosion protection).
3. Aluminum is a good conductor of electricity and heat. The crystal form of aluminum emery is suitable for abrasive materials and cutting tools because of its high hardness.
Various electrolytic coloring mainly include: imitation stainless steel color, bronze color, black oxidation, golden oxidation and so on.
Oxidation coloring is done artificially to oxidize aluminum and its alloys on the surface. The oxidation coloring methods of die-cast aluminum mainly include chemical coloring, electrolytic coloring and natural coloring:
Chemical coloring immerses the oxidized aluminum material in an organic or inorganic dye solution, and the dye penetrates into the pores of the oxide film to cause chemical or physical action to color. The chemical coloring equipment is simple, low-cost, and has a wide variety of colors, but it has poor light resistance and corrosion resistance and is only suitable for interior decoration.
Electrolytic coloring of the aluminum material after oxidation treatment is carried out in a single metal salt or multiple metal salt aqueous solutions for secondary electrolysis. Under the action of an electric field, metal cations penetrate into the pores of the oxide film and deposit on the bottom of the hole, thereby making the oxide film Produces bronze, brown, gray, red, cyan, and blue tones.
Naturally colored aluminum is a method of coloring at the same time as anodizing. There are alloy color method and solution color method. The alloy color development method is to control the aluminum alloy components to obtain different colors; the solution color method is also called the electrolytic color development method, which controls the color tone by controlling the composition of the electrolyte and the electrolysis conditions. In actual production, organic acid is generally used as electrolyte for natural coloring, and a small amount of sulfuric acid is added to adjust PH.
Link to this article：Application and coloring method of aluminum oxidation of die casting
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