Stainless steel and Passivation

|Passive layer

Stainless steel has the remarkable property of being naturally resistant to corrosion due to the presence on its surface of a very thin layer of oxide rich in chromium and which forms spontaneously on contact with air. This layer is said to be “passive” because it prevents the metal from interacting with its environment. Under some circumstances, this passive layer may be damaged and locally lose its resistance to corrosion.


|Passivation, to recreate a protective layer

The natural passivation process may take several days. After degreasing for example, it is highly recommended to recreate a protective layer for the stainless steel within a very short time in order to avoid any risk of contamination or oxidation starting. After this passivation, a new layer of chromium oxide forms and naturally protects the metal from external damage.


|Passivation, a specific treatment

Passivation treatment of stainless steel with an acid and oxidising solution, normally nitric acid or citric acid, facilitates the development of a quality passive layer.


|Technochim – Large size baths

Technochim has various citric acid and nitric acid passivation baths. The baths are able to accommodate very large bulky parts due to their considerable size (7m x 2.5m x 3m).

On its customers’ sites, Technochim operates according to current procedures.