AN ACOUSTIC-EMISSION TECHNIQUE FOR MONITORING PITTING CORROSION OF AUSTENITIC STAINLESS-STEELS

An acoustic emission (AE) technique was used to detect and study the d evelopment of pitting corrosion on AISI 316L austenitic stainless stee l 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 ob served between AE activity and pitting rate. The exact nature of AE so urces within pits is not identified clearly but the results demonstrat e that an acoustic emission technique can be used to detect and even m onitor the occurrence of such phenomena.