Stainless steels (SS) with a chrome content of approx. 12% are able to spontaneously build up passive layer under humidity conditions. Stable passive alloys can be recognized by the fact that they have only a very low corrosion current density thereby ensuring that there can’t be any notable corrosion. Under these conditions the material forms a resistant, protective, but very thin chromium oxide layer on the surface. This barrier ensures that the external current conduction to the surrounding medium practically grinds to a halt. The material behaves in a similar manner as would a precious metal.

- Preferential points of attack

- The route to a better passive layer

- Electro-polished surfaces