Kinetic analysis of the quasi-stable pitting propagation in the 304 SS based on the asymmetrical electrochemical noise

A slightly asymmetrical electrode pair configuration was employed on the 304 SS to promote the possible preferential pitting propagation on one electrode, while the other was relatively quiet. The pitting propagation kinetics was analyzed based on the estimated anodic current according to an allocation model as validated by the microscopic examination. The quasi-stable propagation mode was revealed due to its kinetic feature in between the metastable and the stable pitting, which resulted in a serious of dispersive pits gathered around some weak sites of the passive film. The proposed electrochemical noise signal collection device as well as the signal processing method may be beneficial for the understanding of the real pit propagation at free potential.