An acoustic emission technique for monitoring pitting corrosion of austenitic stainless steels

An acoustic emission (AE) technique was used to detect and study the development of pitting corrosion on AISI 316L austenitic stainless steel in laboratory experiments. Tests were conducted at room temperature in 3% NaCl solution acidified to pH 2, at the free corrosion potential or with applied anodic polarization. It appears that AE signals were easily detected during pitting corrosion and a good correlation was observed between AE activity and pitting rate. The exact nature of AE sources within pits is not identified clearly but the results demonstrate that an acoustic emission technique can be used to detect and even monitor the occurrence of such phenomena.