INITIAL-STAGES OF CATHODIC BREAKDOWN OF THIN ANODIC ALUMINUM-OXIDE FILMS

The cathodic breakdown of thin anodic oxide films on aluminium (3-15 n m) was monitored by current transients of potentiostatic pulse experim ents, electrochemical impedance spectroscopy and simultaneously record ed optical reflectivity. The time to breakdown t(B) taken from current transients as the point of inflection, varies in a very wide range fr om 10(-3) to 10(6)s and depends clearly on the film thickness and on t he polarization potential, A mechanism of the cathodic breakdown accor ding to the experimental results is discussed.