Please note that the passivation process is an optional service provided by PRIMUS

What is Passivation?

Passivation is the chemical treatment of stainless steel with a mild oxidant, such as a nitric acid solution or hydrogen peroxide, for the purpose of enhancing the spontaneous formation of the protective passive film.

The passivation process removes “free iron” contamination left behind on the surface of the stainless steel from machining and fabricating. These contaminants are potential corrosion sites that could result in premature corrosion and ultimately result in deterioration of the component if not removed.

In addition, the passivation process facilitates the formation of a thin, transparent chromium oxide film that protects the stainless steel from selective oxidation (corrosion).

PRIMUS Passivation Process

The PRIMUS process begins with a thorough cleaning of the metal. This is done to remove oils, greases, forming compounds, lubricants, coolants, cutting fluids and other undesirable organic and metallic residue left behind because of fabrication and machining processes.

After removing organic and metallic residues, PRIMUS pressure vessels are passivated with a hydrogen peroxide solution using the Avesta FinishOne Passivator 630 System. Avesta Finishing Chemicals is located in Malmo, Sweden and supplies equipment and chemicals to the USA market through Avesta Welding LLC located in Stafford, TX.


When the passivation option is ordered, PRMUS provides the end user a signed quality document detailing that the passivation process was completed on a specific pressure vessel.

Have a question or having difficulties? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at

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