Stainless steel depends on the alt-thin and strong chromium rich oxide film on its surface to prevent the oxygen atom infiltrating and oxidizing. And for one reason, this film was destroyed, the oxyen atom in the air will infiltrate to form loose iron oxide. The metal surface will be corroded and rusted. There are many forms of destroying this film. We often see these:
1. The surface of stainless steel has attachment with other metal dust and metal metal particles. In the west air, the condensate between attachment and stainless steel will connect them into a micro battery. And then initiating an electrochemical reaction and destroying the protective film. It is called electrochemical corrosion.
2. The surface of stainless steel contains acids, bases, and salt substances. In the presence of water and oxygen, It constitutes an organic acid, and the organic acid corrodes the metal surface for a long time.
3. The surface of stainless steel adheres to substances containing acids, alkalis and salts (such as alkali water and lime water splashing from the decoration walls), causing local corrosion.
4. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide and nitrogen oxide), when encountering condensed water, it will form liquid spots of sulfuric acid, nitric acid and acetic acid, causing chemical corrosion.
The above conditions can cause damage to the protective film on the stainless steel surface and cause rust. Therefore, to ensure that the metal surface is permanently bright and not rusted, we recommend:
1. The surface of decorative stainless steel must be cleaned and scrubbed frequently to remove attachments and eliminate external factors that cause modification.
2. 316 stainless steel should be used in seaside areas, which can resist seawater corrosion.
3. Different materials of stainless steel are used in different places. Generally, 304 is used as the standard for decoration, but it is not suitable for seaside use, because it does not have corrosion resistance.