Functional Surface Properties of Stainless Steels

Parts from stainless steels owe their chemical resistance to the functional properties of their surfaces. They are responsible for the corrosion resistance and also for other properties like adhesion of substrates or ease to clean. The passive layer forms the phase boundary between metal and environment. It is formed either spontaneously during the fabrication or can be produced in an accelerated way by specific chemical treatments. The quality of the passive film is dependant of the alloying content of the metal, but also largely influenced by other factors like fabrication processes, surface topography and type of mechanical and chemical surface treatment. The passive layer is also a kind of living system whose properties and stability is largely influenced by the environment where it is used in. Combination of special electrochemical techniques in combination with measurements of the surface energy are shown to be useful tools to characterize the functional surface properties. They are used to study the individual and synergic influences of mechanical and chemical surface treatments on these properties.