A statistics-based mathematical treatment was used to compare the pitting behavior of Cl-implanted Al to the behavior of nonimplanted Al. Although pitting potentials for both types of samples fall within a similar potential range, the pit germination rates are much higher for the implanted samples. Differences in germination rates are attributed to the Cl adsorption/absorption and/or Cl migration processes that are bypassed by implanting Cl directly into the aluminum oxide. (C) 2004 The Electrochemical Society.