Stainless steel passivates naturally whenever a clean surface is exposed to an environment that can provide enough oxygen for it to form a chromium rich oxide surface layer.

This is an instant and automatic natural process in an environment with sufficient oxygen. The passive layer does however increase in thickness for some time after its initial formation.

Natural conditions, such as air or water, create and maintain the corrosion resistant surface layer in passive state. This self-healing surface protection system allows stainless steels to maintain their corrosion resistance even if the surface is mechanically damaged.

In order for the passive layer to form correctly, the stainless steel requires either an optimally sterile and contamination free environment or chemical treatment. By enriching the surface with chromium electrochemically, we are able to achieve the best possible passive layer for stainless steel.

There are several tests for inspecting passivated stainless steel surfaces. Most commonly used standards are ISO EN 9227:2012 and ASTM A967- 13.