In the field of metal surface treatment, passivation and sealing both play an important role. Electroplating is a common method of rust prevention, while passivation and sealing are often used as further protective measures. So, is the passivation treatment after electroplating equivalent to sealing? What are the differences in the treatment effects of the two?
Author: Marisa
In the field of metal surface treatment, passivation and sealing both play an important role. Electroplating is a common method of rust prevention, while passivation and sealing are often used as further protective measures. So, is the passivation treatment after electroplating equivalent to sealing? What are the differences in the treatment effects of the two? Let's discuss it together.
First understand the mechanism of action
Passivation agent: Passivation treatment is to form a dense passivation film on the metal surface to isolate the metal from external oxygen and moisture, prevent the metal from oxidation reaction, and thus extend the service life of the metal. Chromium-free passivation agent is usually used for passivation treatment, which is suitable for metal materials such as stainless steel, aluminum alloy, and galvanized steel.
Sealing agent: Sealing treatment is to form a thin film on the metal surface to fill and seal the pores on the metal surface, thereby improving the corrosion resistance, sun resistance, wear resistance and insulation of parts. Sealing treatment can make up for the defects of the anodized film or phosphating film on the metal surface, making it denser and more stable.
Secondly, start from the application scenario
In a humid and corrosive environment, passivation treatment may be more advantageous because its passivation film can more effectively isolate moisture and oxygen and prevent metal corrosion. In situations where wear resistance, light resistance and insulation need to be improved at the same time, sealing treatment may be more appropriate. However, it should be noted that the contribution of sealing treatment to improving corrosion resistance may be relatively small.
In practical applications, passivation and sealing can complement each other. Galvanized metal can be first passivated to form a dense oxide film or chemical conversion film to improve the corrosion resistance and stability of the metal. Then, sealing can be performed to seal the tiny pores and cracks on the metal surface to further enhance the metal's rust resistance.
Summarize
The main difference between metal passivators and metal sealers is their mechanism of action. Metal passivators prevent further oxidation and corrosion of metals by forming a thin passive film on the metal surface, whereas metal sealers prevent metals from coming into contact with corrosive substances in the surrounding environment by forming a protective film on the metal surface.