Sacrificial anode: Electrochemical oxidation of metals or alloys. The metal or alloy 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 performance, such as surface coloring, improves corrosion resistance, enhances wear resistance and hardness, and protects the metal surface. For example, aluminum anodizing, the aluminum and its alloys are placed in the corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.) as the anode, under certain conditions and the application of current, electrolysis. The aluminum or its alloy of the anode is oxidized, and a thin layer of aluminum oxide is formed on the surface, with a thickness of 5-20 microns, and a hard anodized film of 60-200 microns. Anodized aluminum or its alloy improves its hardness and wear resistance, up to 250 ~ 500 kg/mm2, good heat resistance, hard anodized film melting point up to 2320K, excellent insulation, resistance to impact The penetration voltage is up to 2000V, which enhances the anti-corrosion performance, and does not corrode in the salt spray of ω=0.03NaCl for thousands of hours. The thin layer of the oxide film has a large number of micropores, which can absorb various lubricants, and is suitable for manufacturing engine cylinders or other wear-resistant parts; the microporous film has strong adsorption capacity and can be colored into various beautiful 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 auto parts, precision instruments and radio equipment, daily necessities and building decoration, etc.