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Passivation of Corrosion Resistant Metals

Ampere Metal Finishing offers specialized services such as passivation to our Toronto clients, as well as businesses across Canada and the United States.

Ampere Metal Finishing administers citric acid passivation in our Toronto facility that fully complies with automotive, aerospace, and military specifications.

What is Passivation?

Passivation is the process of removing iron and iron compounds from the surface of stainless steel alloys. These iron contaminants are invisible to the naked eye and can result from improper cleaning or storage. Contamination can also occur on the surface of the metal as a result of grinding, machining and other manufacturing operations. Sulfur, which is added to some alloys for increased machinability, can also increase the chances of corrosion to occur on stainless steel. Passivation of stainless steel will thus remove any sulfide contamination that may be present.

Passivation of Stainless Steel

Passivation of stainless steel can be accomplished chemically using formulations of nitric acid or citric acid. These formulations have been developed to achieve the removal of contaminants from the various stainless steel alloys (300 series, 400 series, P.H. Alloys, etc.), while at the same time avoiding any removal of the stock alloy. It should be noted that passivation of stainless steel does not remove heat staining that results from grinding, welding or heat treating.
Heat stains and certain other types of soils should be removed by acid cleaning (pickling) the stainless steel prior to the passivation process. If you require passivation in Toronto or anywhere in Canada or the United States, our technical representatives can assist you in determining your specification requirements.

Passivation Specifications

  • AMS-QQP-35
  • ASTM A380
  • ASTM A967
  • MIL-F-14072
  • MIL-S-5002
  • MIL-STD-171