Investigation of pitting corrosion of stainless steel by means of acoustic emission and potentiodynamic methods

Measurements of pitting corrosion by potentiodynamic method and also by acoustic emission technique were carried out simultaneously. Cumulative distribution function of pitting corrosion (CDF_P) occurrence was determined based on the results of potentiodynamic measurements. Independently cumulative distribution function of acoustic events (CDF_AE) was found. The correlation analysis of both distributions was also performed. The occurrence of pitting corrosion was checked by metallographic observation. The measurements proved that observable acoustic activity is an effect of hydrogen evolution inside the pits. The random character of acoustic events during polarization, statistical analysis and existence of pits are good confirmation.