ABSTRACT

The acoustic emission (AE) technique was used to study the development of pitting corrosion on AISI304L and 316L austenitic stainless steel, in a 3% NaCl solution acidified to pH 2. In order to validate the use of this Non-Destructive Technique for on-site corrosion monitoring, both applied current density and AE activity were recorded during potentiostatic polarisation tests on different alloys. It appears that for the three types of studied samples, pit development is emissive after a time delay which is directly linked to the sensitivity of the material towards pitting. Moreover, it appears that the size of the pits is not a discriminating criteria for a pit to be emissive. Therefore, pitting development can be followed by acoustic emission, whatever the type of austenitic stainless steel or amount of inclusions. This result is encouraging for the industrial detection of pitting evolution.