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What Is the Passivation Process?

The passivation process is a method of improving the corrosion resistance of stainless steel parts by removing ferrous contaminants like free iron from their surface, restoring them to their original corrosion specifications.

To passivate stainless steel parts, they must be submerged in a chemical solution of citric acid or nitric acid for a certain period of time and at a certain temperature. This removes foreign matter like free iron from the surface, but does not remove the heat tint or oxide scale that may be left behind by welding or heat treating. The passivation process improves corrosion resistance and leaves a clean finish, but ultimately does not change a part’s appearance nor make it visibly brighter.

By comparison, electropolishing removes burrs, heat tint and oxide scale and makes parts made from a wider variety of stainless steel and other metal alloys visibly brighter.

While you can passivate stainless steel to improve its corrosion resistance, not all grades are suited for this process, and some parts may require additional cleaning operations beforehand.

Contact us to learn more about the passivation process

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Frequently Asked Questions

What services does Able Electropolishing provide?

We provide electropolishing, nitric & citric passivation, and vacuum vapor degreasing.

What are the maximum part sizes that can be processed for electropolishing, passivation, and vapor degreasing?

Electropolishing:

  • 300 & 400 series stainless steel: 108” Length x 41” Width x 42” Height
  • Copper, brass, aluminum, steel, and nickel alloys: 72” Length x 14” Width x 17” Height (best results are achieved on parts that are no larger than 12” square)
  • Titanium, Nitinol, tungsten, and niobium, etc. (refractory metals): 26” Length x 8-3/4” Width x 9-3/4” Height

Passivation:

  • Standard nitric acid passivation: 72” Length x 30” Width x 30” Height
  • Nitric acid/sodium dichromate: 20” Length, 20” Width x 20” Height
  • Citric acid: 26” Length x 18” Width x 15” Height

Vapor degrease:

  • Vapor degrease (vacuum): 23” Length x 16” Width x 10” Height

Note: If there is a question regarding our capabilities, please email a print for review to sales@ableelectropolishing.com.

What information do you require in order to receive a quotation?

We need a copy of the drawing, service needed, lot and annual quantities, process specification and packaging requirements.

What is your standard lead-time?

Standard delivery is 3 to 5 working days after receipt of order. Next day and same day services are offered at an additional cost. Please contact our sales department for further details.

What is the difference between passivation and electropolishing?

Passivation is a chemical process designed to remove free iron and other contaminants from the part surface. Electropolishing is an electro-chemical process that removes surface metal which improves micro finish, provides deburring and adds to the aesthetics of your part.