Acoustic emission during pitting corrosion of 304 stainless steel

Acoustic emission (AE) during pitting corrosion of 304 stainless steel (304 SS) in H2SO4 solutions with different pH values and Cl− concentrations was studied. Two types of AE signals are detected in all solutions. Each type of signals is characterized by AE parameters (rise time, counts number, duration and amplitude) and waveform carefully. It is believed that the hydrogen bubbles evolution inside the pits is the AE source.

Research highlights
► Two types of AE signals are detected in all solutions.
► Duration and amplitude seem to be better to classify different pitting steps.
► Hydrogen bubbles evolution is believed to be AE source during pitting corrosion.