For acoustic emission studies, all electrochemical tests were conducted using an Interface 5000 potentiostat (Gamry, U.S.A.) with the electrical connections set-up as shown in Figure (a). Data obtained for both set-ups were found to match closely with similar polarization curves and voltage fluctuation measurements. For the acoustic emission experiments, the data were collected following the same procedure as that used for the voltage fluctuation experiments with the exception of the timings for each step. Each current step was held for 60 s with 120 s rest periods between. This increase in time allowed for more statistically significant acoustic emission data to be collected.