Aerospace Material Specification
[AMS 2700 E]
This specification covers the requirement for a process to assure removal of free iron or other less noble contaminates from the surfaces of corrosion resistant steel parts.
Passivation methods covered by this specification are as follows:
Method 1: Passivation in Nitric Acid
Method 2: Passivation in Citric Acid
Method 1 shall be used unless Method 2 is authorized by the cognizant engineering organization.
More details (pdf) – coming soon.