The principle and treatment process of stainless steel passivation

source:RUIHONG FASTENER  author:RUIHONG FASTENER release date:2021/10/28 269

1. The principle of passivation treatment can be explained by film theory, that is, passivation is due to the interaction of metal and oxidizing medium, and a very thin (about 1nm), dense, covering performance will be formed on the metal surface during the action. A good passivation film that can be firmly attached to the metal surface. This film exists as a separate phase, usually a compound of oxygen and metal. It plays the role of completely separating the metal from the corrosive medium, preventing direct contact between the metal and the corrosive medium, so that the metal basically stops dissolving and forming a passive state to achieve the purpose of anti-corrosion and anti-rust.

2. Advantages of stainless steel passivation treatment:

(1) Salt spray resistance test can be improved by 5-20 times;

(2) It can be used repeatedly, and the cost is low;

(3) Do not change the color of the workpiece, and the size of the workpiece;

(4) Through the national standard blue dot method, no blue dot will appear for more than 35 seconds;

(5) Stainless steel passivation solution is simple to use, soaking at room temperature is enough;

(6) Environmental protection and low cost (2/3 cost savings compared to outsourcing processing);

(7) There is no need for special equipment and strict processing conditions, just a few general plastic tanks.

3. Stainless steel passivation treatment process:

1. Degreasing and degreasing, if you are sure that there is no oil on the surface of the workpiece, you can omit this step;

2. Activation, soaking time is 2-5 minutes, if you are sure that there is no rust, welding spot and other impurities on the surface of the workpiece (such as a newly polished workpiece), you can omit this step;

3. Passivation must go through the process. The soaking time is 30 minutes, the longer the time, the more complete the passivation film;

4. Neutralization, soaking time is 3 minutes, if the surface shape is simple, there is no gong pattern, no blind holes, this step can be omitted;

5. To pass pure water, it must go through the process, and the time is 3 minutes.