Mechanism of pit nucleation by electrical breakdown of the passive film

Based on the similarity between the electrical breakdown of insulators and the pitting breakdown, the mechanism of the breakdown of passive film of transition metals in a chloride solution is described. It is proposed that nucleation of pits occurs by electrical breakdown, probably by the Zener mechanism. Creation of a very high current locally destroys the passive film and causes the dissolution of the metal forming metastable or stable pits. (C) 2002 Published by Elsevier Science Ltd.