What is the purpose of trivalent chromium blue zinc passivation in the alkaline galvanizing process?
1. Enhance the corrosion resistance of the galvanized coating
As zinc is an amphoteric metal, it reacts with both acids and bases. Zinc itself is not prone to natural passivation. In the atmosphere, the electro-galvanized layer is quickly corroded, eventually forming white basic zinc carbonate corrosion products and growing white ash and white fuzz. The main purpose of passivation is to enhance the anti-corrosion ability of the zinc coating. A good color dull layer can increase the anti-corrosion ability by 5 to 40 times.
2. Use the pretreatment for painting
The porous passivation layer can enhance the adhesion between the coating and the zinc layer. Some electrical appliance enclosures and the like only undergo surface coating treatment. When applying coating locally, the uncoated parts are directly used for rust prevention.
3. Endow the workpiece with various tones and certain functions
Direct passivation can result in various tones such as rainbow, blue-white, silver-white, golden yellow, and black, depending on the passivation process. After passivation, coloring or dyeing can also obtain a richer variety of colors. Black passivation has functions such as matting and heat absorption. Different tones can be matched with the overall color of the machine, making the appearance more harmonious and beautiful, and achieving a certain decorative effect.
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Guangdong Bigely Technology Co., Ltd. ,founded in 2003, is a high-tech enterprise integrating R & D，production, sales and service, specializing in the production of electroplating additives. As a famous electroplating additives source manufacturer in China, our products are widely used to meet the plating needs of different industries and exported to many countries from all over the world. They can meet the environmental protection standard after use, mainly used in automobile parts, sanitary ware, electronic products, hardware, furniture, building accessories and other fields.
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