July 18, 2025
Passivation is a chemical process that uses a mild oxidizing agent, such as a mineral or organic acid solution, to promote the removal of excess iron from the surface of the stainless steel. This treatment will enhance the formation of a chromic oxide layer, thereby enhancing its corrosion-resistant properties.
Why Use a Passivation Machine?
Passivation is an essential process for making stainless steel rust-resistant. The process has been a best practice for steel production since the 1900s because of its ability to:
- Create a chemical barrier against rust.
- Extend the steel’s life span.
- Remove harmful contaminants from a piece’s surface.
How Does a Passivation System Work?
As an iron-based alloy, stainless steel consists of iron, chromium and nickel. The corrosion-resistant properties of stainless steel come from its chromium content. When exposed to oxygen, the chromium transforms into a layer of chromium oxide that protects the steel from rust.
Passivation works by immersing stainless steel parts into an acid bath that dissolves the surface’s iron particles while maintaining the chromium content. Removing the iron with acid allows the steel to develop a surface higher in chromium than the underlying steel.
Once you remove the stainless steel from its acid bath, oxygen reacts to the chromium-rich surface and forms a thick layer of protective chromium oxide. This thicker layer drastically reduces the risk of corrosion and extends the part’s life span.