Localized corrosion and electrochemical current noise

摘要

The analysis of current transients resulting from metastable pitting events is a useful method for the investigation of the mechanisms of localized corrosion. Until recently, the noise of the passive current limited the detection of smaller metastable and pit initiation events. The analysis of the noise itself was not very successful, and was only a disturbing factor in the detection of the current transients. Improvements made in electrochemical data acquisition instrumentation and the appearance of novel methods of analysis, such as microelectrochemistry, now enables the analysis of the electrochemical noise. The investigation of localized corrosion on stainless steels reveals, that the current noise is influenced by numerous small pit initiation events due to the dissolution of non-metallic inclusions. This observation and the dependence on surface area of the current noise help in clarifying the mechanistic aspects of pitting corrosion.