Sacrificial anode: electrochemical oxidation of metal or alloy. A metal or alloy product is used as an anode, and an oxide film is formed on the surface by electrolysis. The metal oxide film changes the surface state and properties, such as surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, and protecting metal surfaces. For example, aluminum anodic oxidation, aluminum and its alloys are placed in the corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.) as the anode, and electrolysis is carried out under specific conditions and applied current. The anode aluminum or its alloy is oxidized to form a thin layer of aluminum oxide on the surface, the thickness of which is 5-20 microns, and the hard anodized film can reach 60-200 microns. The anodized aluminum or its alloy improves its hardness and wear resistance to 250～500 kg/mm2, good heat resistance, the melting point of hard anodized film is as high as 2320K, excellent insulation and shock resistance The breakdown voltage is as high as 2000V, which enhances the corrosion resistance and does not corrode in ω=0.03NaCl salt spray for thousands of hours. There are a large number of micropores in the thin oxide film, which can absorb various lubricants, which is suitable for manufacturing engine cylinders or other wear-resistant parts; the film has a strong adsorption capacity and can be colored into various beautiful and gorgeous colors. Non-ferrous metals or their alloys (such as aluminum, magnesium and their alloys, etc.) can be anodized.
Sacrificial anode: widely used in mechanical parts, aircraft and automobile parts, precision instruments and radio equipment, daily necessities and architectural decoration