The present study has shown that only pickling is not the decisive
step for reaching the appropriate corrosion protectiveness
on type 304 stainless steel surfaces. It was corroborated by
ECN measurements under anodic polarisation that the susceptibility
to pitting corrosion of type 304 stainless steel surfaces
depends strongly on the conditions at which the surface is subsequently
passivated. The self-adjustment mechanism of the
passive film being supported by the strong cathodic process in
a high-humidity atmosphere reduced significantly the susceptibility
to pit nucleation of the type 304 stainless steel. In
contrast, a subsequent exposition of the pickled surface to a
low-humidity environment leads to a less stable passive film,
and therefore, more susceptible to metastable pitting corrosion.
The differences in the susceptibility to metastable pitting corrosion
determined between these pickled surfaces can be ascribed
to the dissimilar chemical stability of their passive layers as
confirmed by ECN measurements on type 304 stainless steel
surfaces under cathodic polarisation.