Elastic recoil detection analysis (ERDA), RBS and TEM study of barrier film formation on Al-4.5 at.% Mg-0.05 at.% Cu alloy
✍ Scribed by Thompson, G. E.; Skeldon, P.; Wood, G. C.; Zhou, X.; Kreissig, U.; Wieser, E.; Habazaki, H.; Shimizu, K.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 172 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0142-2421
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✦ Synopsis
The inÑuences of magnesium upon the formation of barrier-type anodic Ðlms on an Al-4.5 at.% Mg-0.05 at.% Cu alloy have been examined by elastic recoil detection analysis, Rutherford backscattering spectroscopy and analytical transmission electron microscopy. The results reveal that magnesium species are distributed uniformly throughout the anodic alumina Ðlm, with magnesium species migrating outwards in the Ðlm approximately twice as fast as Al3' ions. Upon reaching the Ðlm surface, the magnesium species are ejected into the electrolyte under the particular conditions of anodizing, whereas Al3' ions are retained within the Ðlm. The oxidation of magnesium results in voids at the alloy/Ðlm interface, which are probably associated with the low Pilling-Bedworth ratio of Mg/MgO relative to that of
The voids are formed in the presence of a high enrichment of copper (to 1.0 Â 1019 Al/Al 2 O 3 . Cu atoms m-2) in the alloy region immediately beneath the anodic Ðlm, with copper species (which migrate outward faster than Al3' ions) present throughout the anodic Ðlm.