1 Pitting corrosion of stainless steel by electrochemical noise technique

Electrochemical noise (EN) corrosion monitoring technique has become an interesting method in corrosion measurement systems. Detection and analysis of early stages of localized corrosion is the best advantage of this testing technique. Signal analyses and understanding the obtained current and potential transients are limited. In this work, the pitting corrosion behavior of 304 and 316 stainless steel in ferric chloride solution was investigated by electrochemical noise measurement technique. Results obtained from current and potential transients were in correlation with surface analysis performed by scanning electron microscopy. Tests were conducted at three different temperatures, 40, 50, and 60°C. Results showed that 304 stainless steel exhibited general corrosion associated with pitting corrosion, this effect increased as temperature increased. 316 stainless steel showed only pitting corrosion with no general corrosion, the effect of temperature on 316 was less.