Magnesium alloy is rich in resources, known as the lightest green metal structural material in the 21st century, China has the largest magnesium resources, and is committed to the development and application of magnesium alloy. As magnesium alloys are susceptible to environmental corrosion, corrosion protection becomes a key issue for industrialization and extensive application of magnesium alloys.
Due to the active nature of magnesium alloy, processed magnesium alloy products are quickly oxidized in the air to produce loose oxide film, which has no anticorrosion ability and poor basic adhesion, and cannot be directly coated on it. It must be pretreated for coating, so as to carry out effective anticorrosion on magnesium alloy. Traditional magnesium alloy surface treatment with chemical oxidation and anodic oxidation method, forming a protective oxide film in the surface of magnesium alloy, but thin oxide film layer, the anti-corrosion performance is poor, must be alkaline primer coating, and through the layers of paint coating to meet the requirements of corrosion of magnesium alloys, suit for large workpiece and anti-corrosion coating, the part with not high demand but cumbersome to operate, and the production efficiency is not high. In recent years, high voltage micro arc discharge anodic oxidation technology has been applied to magnesium alloys. The ceramic film obtained has high hardness, good wear resistance, high insulation resistance and improved corrosion resistance. However, it has some disadvantages, such as high brittleness of the film, high energy consumption and operation under high voltage, which is not suitable for large-scale use. The film layer is not conductive and can only be sprayed with organic paint, which consumes a lot of organic solvents and is easy to pollute the environment and cause potential safety hazards.
