Electrochemical Society Proceedings
Salt Lake City, Utah
The effect of impurities on formation of interfacial metallic voids, during uniform dissolution of aluminum in 1 M NaOH, was investigated. These voids are thought to act as initiation sites for pitting. Foils of three different bulk purities were used: 99.98% (3N), 99.997% (4N), and 99.9995% (5N). Positron Annihilation Spectroscopy (PAS) and Atomic Force Microscopy (AFM) revealed that nm-scale voids were formed by dissolution in each foil. The void volume fraction increased to a maximum during dissolution, at a time which increased with foil purity. The concurrent accumulation of near-surface Cu and Fe impurities during caustic etching was characterized using Rutherford backscattering spectrometry (RBS). For the three foils, a correlation of void volume fraction with Cu surface concentration was suggested. Processes involving Cu impurities may then at least partly control the formation of voids.
© The Electrochemical Society, Inc. 2002. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS).
The Electrochemical Society
Huang, Renchun; Hebert, Kurt R.; Gessmann, Thomas; and Lynn, Kelvin G., "Effect of Impurities on Interfacial Void Formation in Aluminum" (2002). Chemical and Biological Engineering Conference Presentations and Proceedings. 15.