A Critical Implanted Cl Concentration for Pit Initiation on Aluminum Thin Films

The pitting potential of pure aluminum thin films in 50 mM K 2 SO 4 was measured as a function of implanted Cl fluence. Samples were implanted with 35 keV Cl + at room temperature using fluences from 2.25 X 10 16 to 3.25 X 10 16 ions cm -2 in increments of 0.25 X 10 16 . An empirical relationship between pitting potential and fluence was found which suggests a critical Cl concentration in the oxide is necessary for pit initiation. No correlation between pitting potential and the measured Cl concentration or distribution in the metal was found.