Time-lapse observation of crevice corrosion in grade 2205 duplex stainless steel

Aoki, So  ; Engelberg, D. L.*

The objective of this study was to investigate and visualize the initiation and propagation behaviour of crevice corrosion in grade 2205 duplex stainless steel by means of time-lapse, in-situ observations. All observed crevice corrosion initiated close to the edge of the washer, where the crevice gap was very tight. Crevice corrosion then expanded underneath the crevice forming disk into areas with wider gaps towards the crevice mouth. This was associated with a rise in anodic current, leading into hydrogen gas evolution within the crevice. Once crevice corrosion reached the crevice mouth, the corrosion propagated Circumferentially, but also in depth.