Citric or Nitric Passivation

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What is Passivation?

Passivation is the chemical treatment for protecting metal from corrosion. The process of passivation is actually a corrosive process in which corrosion occurs on the surface, forming a thin layer over the surface, creating a natural seal.  The process of passivation is something that accelerates the process, which (passively) occurs over time, thus the term “passivation.”

Why Passivize Fittings?

Industry standards require that all stainless-steel fittings are passivated. Though there are multiple methods of passivation, OmegaOne passivates our stainless-steel fittings in compliance with ASTM A967. 

ASTM A967 discusses two, nitric or citric.  Both methods of passivation are intended to remove free iron particles from the surface of the metal.  Iron particles or other contaminants may be present from the machining process when the fitting is manufactured.  Nitric and citric passivation both make stainless steel more resistive to oxidation (rust-resistant).

OmegaOne uses the citric method of passivation, performing a copper-sulfate test to confirm that free iron and other potential contaminants have been removed from the surface.  OmegaOne selected the citric method of passivation as this method because it is environmentally friendly.  However, the citric method of passivation may not be acceptable for certain applications.

MS and AMS Passivization Certification

Some specifications, such as Aerospace Material Specification (AMS), require passivization per SAE AMS 2700. This standard recognizes two methods of passivization, citric and nitric. Use of citric passivization is permitted by AMS 2700 when approved by the end user. If you have a customer that’s requiring nitric passivization per the SAE AMS 2700, contact our sales team to ensure compliance with this standard.

If you have any questions about our passivation processes or to get information about our fittings, we are happy to help. We make finding the right fittings easy!

Passivation Technical Bulletin