Study of the anodic oxidation of stainless steel alloys, and their constituent elements, in acidic electrolytes

Abstract

The chronoamperometric behaviour of certain stainless steel alloys and their constituent metals in various electrolytes indicates metal dissolution followed by nucleation and growth of anodic surface films at transpassive potentials. These processes resulted in the appearance of previously unreported rising current transients whose characteristic form is sensitive to the prevailing nucleation and growth mechanism. Rising current transients have been observed for Fe, Mo, Cr and FexCr (x= 16, 18, 20, 23), 444, 4732, 4733, 304L and 316L stainless steels. The temperature, alloy and electrolyte composition were shown to have a significant influence on the form of the rising current transients. A phenomenological model is proposed to describe the nucleation process on the metals under investigation.