The study of the volume expansion of aluminum during porous oxide formation at galvanostatic regime
| Autor: | Vitaly Sokol, V. Parkoun, I. Vrublevsky, J. Schreckenbach, Günter Marx |
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| Rok vydání: | 2004 |
| Předmět: |
Anodizing
Chemistry Scanning electron microscope Oxalic acid technology industry and agriculture Analytical chemistry Oxide General Physics and Astronomy Mineralogy Sulfuric acid Surfaces and Interfaces General Chemistry equipment and supplies Condensed Matter Physics Microstructure Surfaces Coatings and Films chemistry.chemical_compound Porous medium Porosity |
| Zdroj: | Applied Surface Science. 222:215-225 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2003.08.014 |
| Popis: | The volume expansion factor of porous alumina, formed by through anodizing of an Al foil of thickness 11.5 mm in the range of current densities of 4–35 mA cm � 2 in oxalic and sulfuric acid at 18–24 8C has been studied. The microstructure of anodizing samples has been observed using scanning electron microscopy. The thickness of obtained porous alumina films was measured by a mechanical profilometer with a computer signal-processing. The volume expansion factor of porous alumina varied from 1.35 to 1.65. Linear dependences were obtained for the volume expansion factor of porous alumina versus the anodizing voltage and the ionic current-density logarithm versus the inverse volume expansion factor. Unlike oxide formation in sulfuric acid, these dependences have two subsequential rectilinear regions in oxalic acid. This peculiarity of the dependences in oxalic acid was explained by formation of a region of the immobile negative space charge in the barrier Al oxide layer and its influence on the ionic transport. # 2003 Elsevier B.V. All rights reserved. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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