Passivation is a chemical surface treatment method that creates or strengthens the protective passive layer on stainless steel surfaces.
During the process, a uniform, permanent chromium oxide layer forms on the surface, effectively protecting the steel against rust and pitting corrosion. At the same time, the treatment removes free iron and other impurities from the surface that weaken corrosion resistance.
Passivation improves the natural corrosion resistance of stainless steel by strengthening the passive layer and removing metallic impurities created during manufacturing. The process restores the steel's original corrosion protection without altering the part's dimensional accuracy or surface structure.
It is suitable for all stainless, acid-resistant and duplex steels, as well as various manufactured components whose corrosion resistance needs to be ensured.
Most commonly used standards: ASTM A967, ASTM A380, ISO 16048.
Stainless steel passivation is necessary whenever the surface's natural passive layer is weakened, discontinuous or contaminated – meaning when the steel's own corrosion resistance is not optimal.
Passivation is an especially critical procedure in the pharmaceutical, food, chemical and offshore industries, where corrosion resistance and cleanliness are essential.
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CEO, Sales
INOX Finland Oy
Pickling removes oxide layers, heat tints and scale from the steel surface. It is especially suitable for treating welded components.
Critical note: after pickling, the surface is highly susceptible to contamination and always requires passivation.
Passivation strengthens and recreates the passive layer, and removes free iron and metallic impurities from the component surface. Passivation is excellently suited as an independent treatment for machined or mechanically processed surfaces.
If the surface does not have:
If deeper surface cleaning is not required, passivation alone is sufficient to restore and strengthen the passive film.
For the most demanding applications and to achieve optimal corrosion resistance, we recommend a combination treatment, where both processes are performed sequentially:
Passivation is essential after pickling: it immediately forms a protective passive layer and eliminates contamination risk, while removing impurities left on the surface.
INOX Finland optimises the properties of stainless steel with chemical treatments. We specialise in bringing up the best in stainless steel. By selecting the right materials and optimising their qualities, we are able to produce the most outstanding results.