What does the term passivation mean?

1 : to make inactive or less reactive passivate the surface of steel by chemical treatment. 2 : to protect (something, such as a solid-state device) against contamination by coating or surface treatment.

What is passivation with Example?

As a technique, passivation is the use of a light coat of a protective material, such as metal oxide, to create a shell against corrosion. When connected to an external power source, the anode material will electrochemically corrode due to oxidation, while the cathode will be subjected to passivation.

What is passivating a weld?

This cleaning process, also known as “passivation”, isn’t just to enhance the looks of the welds but also prevents corrosion. In other words, passivation is the process of restoring the damaged oxide layer to prevent corrosion in stainless steel.

What does passivating stainless steel do?

Passivation is a widely-used metal finishing process to prevent corrosion. In stainless steel, the passivation process uses nitric acid or citric acid to remove free iron from the surface. The chemical treatment leads to a protective oxide layer that is less likely to chemically react with air and cause corrosion.

What materials can be passivated?

Chemical layers that protect metal from corrosion

  • Stainless steel has a passivation layer that protects it from corrosion.
  • Passivation was discovered during explorations of electrochemical reactions.
  • Stainless steel alloys include chromium and other elements to create a passive layer.

How do you passivate?

Passivating stainless steel is typically accomplished in industry by dipping the part in a bath of nitric acid. Nitric acid dissolves any free iron or other contaminants from the surface, which cleans the metal, and it re-oxidizes the chromium; all in about 20 minutes.

Why is passivation needed?

Passivation is required to restore or enhance the chromium oxide film on the stainless steel surface when it has been manipulated by surface finishing, welding, grinding, external contamination, etc.

Does passivation prevent rust?

Passivation is the process of treating or coating a metal in order to reduce the chemical reactivity of its surface. In stainless steel, passivation means removing the free iron from the surface of the metal using an acid solution to prevent rust.

Which metals can be passivated?

Stainless steel and aluminum are both self-passivating materials, but they are not impervious to corrosion. Irregularities in grain, created by manufacture or heat treatments, can create weakness. Surface deposits of oil or other chemicals also may interrupt the passive film.

How do you passivate at home?

Where normally you would use about 1 oz in 5 gallons to sanitize, for passivation you need to use 1 oz per gallon. Soak the parts in concentrated star-san for 20-30 minutes at room temperature, and then allow them to air dry overnight so the oxygen can passivate the metal.