Electrophoretic coating of magnesium alloy

Magnesium alloy is rich in resources, known as the lightest green metal structural materials in the 21st century, China is the country with the largest magnesium resources, and is committed to the development and application of magnesium alloys. Since magnesium alloy is easily corroded by environmental media, anti-corrosion has become a key issue for industrialization of magnesium alloy and popularization and application of a large number of deep processing.

Due to the active nature of magnesium alloy, the processed magnesium alloy products are quickly oxidized in the air to produce loose oxide film, which has no anti-corrosion ability and poor basic adhesion, and cannot be directly painted on it, and must be pre-treated to be painted, so as to effectively prevent corrosion of magnesium alloy. The traditional magnesium alloy surface treatment adopts chemical oxidation and anodic oxidation methods to form a protective oxide film on the surface of magnesium alloy, but the oxide film layer is thin and has poor anti-corrosion performance, so it must be coated with alkaline primer and multi-layer paint to meet the anti-corrosion requirements of magnesium alloy. It is suitable for painting large workpieces and workpieces with low anti-corrosion requirements, but the operation is cumbersome and the production efficiency is not high. In recent years, high voltage micro-arc discharge anodizing technology has been used on magnesium alloys. The ceramic film obtained has high hardness, good wear resistance, high insulation resistance, and great anti-corrosion performance. However, there are some weaknesses such as brittle film, high voltage operation, great energy consumption, and not good for large-scale use. The film layer is not conductive, and can only be painted with organic paint, which consumes a lot of organic solvents, which is easy to pollute the environment and cause security risks.