The passivation process of stainless steel is a chemical treatment that improves the corrosion resistance of stainless steel by forming a dense, stable oxide film (usually chromium oxide, Cr2O3) on its surface. Passivation not only restores the passivation film of stainless steel that has been damaged during processing and welding, but also further enhances its corrosion resistance. The following
Author: Anna
The passivation process of stainless steel is a chemical treatment that improves the corrosion resistance of stainless steel by forming a dense, stable oxide film (usually chromium oxide, Cr2O3) on its surface. Passivation not only restores the passivation film of stainless steel that has been damaged during processing and welding, but also further enhances its corrosion resistance. The following is a detailed description of the stainless steel passivation process:
1. The basic principle of passivation
The main principle of passivation is to use oxidizing agents to react with chromium on the surface of stainless steel to produce a dense layer of chromium oxide. This chromium oxide layer has high chemical stability and can effectively isolate the metal from the corrosive medium, thus preventing further corrosion.
2. Selection of passivation solution
Commonly used passivation liquids include nitric acid, hydrofluoric acid, citric acid and so on. Passivation solutions of different compositions are suitable for different types of stainless steel. For example, nitric acid is usually used for austenitic stainless steel (such as 304, 316), while hydrofluoric acid is suitable for ferritic stainless steel (such as 430).
3. The process steps of passivation
4. Inspection after passivation
The surface of stainless steel after passivation needs to be tested to ensure the quality of the passivated film. Commonly used detection methods include:
The stainless steel passivation process is to chemically form a dense chromium oxide film on the metal surface to improve its corrosion resistance. Passivation treatment requires strict control of process parameters, including the selection of passivation solution, passivation time and temperature, etc., to ensure the quality and uniformity of the passivation film.
In addition, the test after passivation is also an important step to ensure the corrosion resistance of stainless steel. Through scientific passivation treatment, stainless steel can maintain its excellent performance in various corrosive environments.