Passivate

Passivation is used to clean and improve the surface condition of stainless steel by dissolving the iron that is embedded in the surface by forming, machining, or other manufacturing steps. If allowed to remain the iron corrodes and often gives the appearance of large or small rust spots on the stainless steel. In order to prevent this condition on the finished parts, they are given a passivation treatment. This treatment, which consists of immersing the stainless steel parts in a solution of citric acid or nitric acid without oxidizing salts for a specific period of time, will dissolve the embedded iron and restore the original corrosion-resistance surface by forming a thin transparent oxide film.

Passivated Surfaces Features:

• Stainless steel does not have to be plated to achieve maximum corrosion protection 
• Provides a superior clean surface
• No rust discoloration of the stainless steel when in service
• Surface preparation for other finishes such as priming or painting
• Passivated stainless steel will not react with other materials because of iron contamination

What are the governing specifications that cover Passivation?

• AMS 2700
• AMS QQ P 35
• ASTM A 380
• ASTM A 967
• MIL S 5002