Anodic oxidation of die casting aluminum is electrochemical oxidation of metal or alloy. Aluminum and its alloys in the corresponding electrolyte and specific process conditions, due to the effect of external current, on the aluminum products (anode) to form a layer of oxide film process. Different from other chemical oxidation processes, it has the effect of reducing natural color. If not specified, it usually refers to sulfuric acid anodizing.
     In anodizing, metal or alloy parts are used as anodes to form oxide films on their surfaces by electrolysis. Metal oxide film changes the surface state and properties, such as surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, protecting metal surface, etc. Aluminum and its alloy are put in corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.) as anode, and electrolysis is carried out under specific conditions and applied current. A thin layer of alumina is formed on the surface of anodized aluminum or its alloy, with a thickness of 5-20 μ m, and a hard anodized film of 60-200 μ M.
    The hardness and wear resistance of anodized aluminum or its alloy are improved to 250-500 kggm2, good heat resistance, melting point of hard anodized film up to 2320k, excellent insulation, breakdown voltage up to 2000V, enhanced corrosion resistance, and no corrosion after thousands of hours in ω = 0.03nacl salt spray. There are a lot of micropores in the thin oxide film, which can absorb all kinds of lubricants, so it is suitable for manufacturing engine cylinders or other wear-resistant parts; the micropores of the film have strong adsorption capacity, and can be colored into a variety of beautiful colors. Non ferrous metals or their alloys (such as aluminum, magnesium and their alloys) can be anodized. This method is widely used in mechanical parts, aircraft and automobile parts, precision instruments and radio equipment, daily necessities and architectural decoration.
    In addition to metals, other substances do the oxidation caused by the anode, also known as "anodizing". In reality, anodizing of aluminum alloy, more, can be applied in daily life, that the characteristics of this process, so that the surface of aluminum produce a hard protective layer, can be used for the production of kitchenware and other daily necessities. But the anodizing effect of cast aluminum is not good, the surface is not bright, and it can only be black. Aluminum alloy profiles die-casting aluminum anodizing color is better.