Under potentiostatic conditions on stainless steel electrodes in chloride solution, a novel electrochemical cell equipped with an ultrasonic transducer has been designed to evaluate the metastable and stable pitting corrosion behaviors. The advantage of the cell is that the rupture of pit cover can be controlled during the metastable or stable pitting growth periods, and in which the effect of the cover on pitting stability is affirmed. Some shallower stable pits, which were formed at higher anodic potential, were found to repassivate after ultrasonic cover rupture due to their shorter diffusional length. in terms of the relative susceptibility to localized corrosion, repassivation potential (E-r) determined by the cyclic potentiodynamic polarization curve was found to describe more properties of the occluded pit cover than the others. (C) 2008 Published by Elsevier Ltd.