Stainless steel is an extremely thin, strong, dense, and stable chromium-rich oxide film (protective film) formed on its surface to prevent the relay of oxygen atoms. Continue to penetrate, continue to oxidize, and obtain the ability to resist rust. Once for some reason, this kind of film has been continuously destroyed, empty Oxygen atoms in gas or liquid will continue to infiltrate or iron atoms in metal will continue to separate out, forming loose iron oxide. The surface is constantly corroded.
There are many forms of damage to this surface film, and the following are common in daily life:
1. Dust or other metal particles containing other metal elements accumulate on the surface of the stainless steel. The condensed water between the object and the stainless steel connects the two into a micro battery, which triggers an electrochemical reaction, and the protective film is damaged. It is called electrochemical corrosion.
2. Organic matter juice (such as melon and vegetable, noodle soup, sputum, etc.) adheres to the surface of the stainless steel. In the presence of water and oxygen, it forms an organic acid for a long time. The organic acid corrodes the metal surface.
3. The surface of stainless steel contains acid, alkali and salt substances (such as alkali water and lime water splashing on the wall), causing local corrosion.
4. In contaminated air (such as an atmosphere containing a large number of sulfides, carbon oxides, and nitrogen oxides), when it encounters condensed water, sulfuric acid and nitrate are formed
The acid, acetic acid liquid point, causing chemical corrosion.
The above conditions can cause damage to the protective film on the surface of the stainless steel chemical pump and cause corrosion.
Post time: Jul-20-2020