Crevice corrosion and pitting detection on 304 stainless steel using electrochemical noise

Abstract

Random fluctuations in current and voltage under free corroding conditions have been measured on austenitic steel 304 in sodium chloride solutions with different aggressiveness. The evolution of these fluctuations in time and frequency domains is analysed and related to the corrosion process on the surface electrode. When the metal is passive, the noise becomes white meanwhile during localised attack changes in the current and voltage can be found. Electrochemical noise (EN) measurements also showed the ability of the technique to distinguish between different corrosion processes such as pitting or crevice corrosion.