Passivation is a process of producing a trivalent or six valence Chromizing Layer on its surface by the action of chromate solution and metal on its surface, also called chromizing. After the prototype has been chemically cleaned, the metal surface is very clean and very active, it’s easy to be corroded. Therefore, the passivation treatment must be carried out immediately to make the cleaned metal surface form a protective film to slow down the corrosion. Passivation is mostly used for surface treatment of aluminum, magnesium and its alloys, and also can form chromium coating on steel. It is often used in conjunction with phosphating, so as to close the pores of phosphating layer and passivate the bare steel in the phosphating layer, so as to inhibit the corrosion effect of the residual phosphating accelerating agent, and further increase the protective power. We know that metal products are easy to be corroded. In order to extend the life of metal products and improve the corrosion resistance of metal products, we must passivate them, such as machinery, aircraft, automobiles and other metal products, which are passivated.
Passivation is a way to transform the metal surface into a state that is not easy to be oxidized and to slow down the corrosion rate of the metal. An active metal or alloy, in which the chemical activity is greatly reduced and a phenomenon of the state of precious metals, also called passivation. Metal corrosion products due to the role of media if have a dense structure, forming a layer of thin, tightly covered on the surface of the metal, while the change of surface state of metal corrosion, become passive.
The Advantage of Passivation
The passivation treatment is simple, easy to use, economical and practical. At the same time, high efficiency corrosion inhibitor and fog suppressant are added to prevent metal from corrosion and hydrogen embrittlement, and to inhibit the production of acid mist. It is especially suitable for small complex workpieces that can not be pasted. We combine the advantages of several passivation processes:
1. Passivation promotes the formation of oxygen molecular structure passivation film on the surface of metal. The film is dense and stable, and it has self repairing function in air. Therefore, compared with the traditional method, the passivation film formed by passivation is more stable and more corrosion resistant.
2. Because the passivation process is non-reactive, the passivator can be added repeatedly, so the life is longer and the cost is more economical.
3. The traditional physical closed method compared with absolute passivated without increasing the workpiece thickness and change the color of the product, improves the precision and added value, make the operation more convenient.