Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9572193 | Applied Surface Science | 2005 | 7 Pages |
Abstract
Chemical dissolution of the barrier layer of porous oxide formed on thin aluminum films (99.9% purity) in the 4% oxalic acid after immersion in 2 mol dmâ3 sulphuric acid at 50 °C has been studied. The barrier layer thickness before and after dissolution was calculated using a re-anodizing technique. It has been shown that above 57 V the change in the growth mechanism of porous alumina films takes place. As a result, the change in the amount of regions in the barrier oxide with different dissolution rates is observed. The barrier oxide contains two layers at 50 V: the outer layer with the highest dissolution rate and the inner layer with a low dissolution rate. Above 60 V the barrier oxide contains three layers: the outer layer with a high dissolution rate, the middle layer with the highest dissolution rate and the inner layer with a low dissolution rate. We suggest that the formation of the outer layer of barrier oxide with a high dissolution rate is linked with the injection of protons or H3O+ ions from the electrolyte into the oxide film at the anodizing voltages above 57 V.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
I. Vrublevsky, V. Parkoun, V. Sokol, J. Schreckenbach,