Document Type

Article

Research Focus Area

Advanced and Nanostructured Materials

Publication Date

2004

Journal or Book Title

Journal of the Electrochemical Society

Volume

151

Issue

1

First Page

B22

Last Page

B26

DOI

10.1149/1.1631821

Abstract

Positron annihilation spectroscopy (PAS) measurements were carried out to characterize open-volume defects associated with anodic oxidation of aluminum. The annihilation fractions with low and high momentum electrons (S and W spectral lineshape parameters, respectively) of the annihilation photopeak were determined, as a function of the positron beam energy. A subsurface defect layer, containing nanometer-scale voids in the metal near the metal/oxide film interface, was found after oxide growth, and was shown to contain new voids created by anodizing. Such interfacial voids in the metal are of interest because of their possible role as corrosion initiation sites. The Sparameter characterizing the defect-containing layer (Sd) was obtained by simulation of the S-energy profiles. On samples with two different surface conditions, Sd remained constant at its initial value during anodizing. Because Sd is related to the void volume fraction in the interfacial metallic layer containing the voids, that result suggests that formation of metallic voids, and their subsequent incorporation into the growing oxide layer, occurred repeatedly at specific favored sites. © 2003 The Electrochemical Society. All rights reserved.

Comments

This article is from Journal of the Electrochemical Society 151 (2004): B22–B26, doi:10.1149/1.1631821. Posted with permission.

Copyright Owner

ECS—The Electrochemical Society

Language

en

File Format

application/pdf

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