Passivation Service

Citric Acid Passivation

All the benefits of nitric acid passivation, yet more efficient and environmentally safe

Under ideal conditions, pure stainless steel (SS) forms an oxide film when exposed to oxygen which protects the SS from corrosion. Under realistic, normal conditions, foreign material in a manufacturing environment, sulfides added for improved machinability or particles of iron from machining may be transferred to the surface of the stainless steel. These all can inhibit the formation of the oxide film which protects stainless steel from corrosion. The contaminants need to be removed down to the surface grain boundaries / structure of the stainless steel surface. This removal and oxide growth process is called passivation.

Passivation is a non-electrolytic process using nitric or citric acid which removes free iron from the surface and forms an inert, protective oxide layer that renders the stainless steel more rust-resistance due to lack of iron to react with the atmosphere.

Greystone Medical offers both citric acid passivation and nitric acid passivation. Our capabilities include:

• Choice of citric or nitric bath
• Certified to ASTM A967, ASTM A380, ASTM F86, AMS-QQ-P-35, AMS 2700

When you choose citric acid passivation, you gain:

• Easier and more efficient removal of free surface ions
• Improvement in both human safety and environmental impact
• Greater results on salt, immersion and humidity tests
• No dichromate used which can be inherent to Nitric passivation processes