The anodic behaviour of cathodically pretreated aluminum electrodes in 0.1M NaCl solution containing citrate ion

We obtain potentiodynamic curves of Al at different scanning rates beginnin g from - 1.8 V in 0.1 M NaCl at pH 4 and in 0.1 M NaCl + 0.06 M citrate at pH 4, 8 and 10; with or without buffered solution. The shapes of these curv es show that the electrochemical and chemical dissolution and precipitation reactions on the Al surface occurs competitively depending on the pH of th e solution, presence of buffer and on the scanning rate. This competition w as also confirmed by i-t curves obtained at constant potential. (C) 1999 El sevier Science B.V. All rights reserved.