Passivation

Passivation is usually done by treating metal parts in acid baths (very commonly using nitric acid or citric acid). During the process, all dirt, oils and other impurities are removed from the metal surface, followed by immersion in the acid solution, promoting the formation of a protective oxide layer. The steps of the passivation process are usually as follows:

1. Cleaning The surface of the metal is cleaned of oil, dirt and other impurities. This step increases the effectiveness of the passivation process because a clean surface allows the oxide layer to form more uniformly.

2. Acid Bath The cleaned metal parts are immersed in an acid solution that will allow the oxide layer to form. This step may vary depending on the type of metal and the level of protection required.

3. Rinsing Metal parts removed from the acid bath are rinsed to remove any acid residue. Usually deionized water is used.

4. Drying The water remaining on the surface of the metal parts must be completely dried. This is the final step of the passivation process and ensures that no moisture remains on the surface of the metal that could cause any corrosion.

Passivation plays an important role in the protection of metal parts used in various industries such as aerospace, automotive, food processing, medical and construction. This process improves the surface properties of the metal, while at the same time increasing its resistance to corrosion and thus extending the product's lifetime.