Pit growth studies in stainless steel foils. I. Introduction and pit growth kinetics

Pits were grown from the edges of thin 304 SS (stainless steel, SS) foils, and the resulting cavities were viewed by video microscopy, allowing the study of real-time pit growth under different applied conditions, e.g. potential and temperature. This method also allowed direct comparison of the current recorded with the development of the pit. All pits developed a lacy metal cover, which was shown to provide a diffusion barrier necessary to sustain stable pit growth, especially in the early stage of a pit's life, Pit growth, morphology and cover formation are explained with the help of a semi-quantitative model based upon concentration gradients and active/passive transitions. Pits grown in plate material and high alloy stainless steel have the same basic morphology. (C) 2002 Elsevier Science Ltd. All rights reserved.