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Article
Participation of Aluminum Hydride in the Anodic Dissolution of Aluminum in Alkaline Solutions
Journal of the Electrochemical Society
  • Saikat Adhikari, Iowa State University
  • Kurt R. Hebert, Iowa State University
Document Type
Article
Disciplines
Publication Date
1-1-2008
DOI
10.1149/1.2883827
Abstract
The mechanism of anodic alkaline dissolution of aluminum was investigated through the analysis of cyclic voltammetry (CV) and potential step experiments. Attention was focused on the role of aluminum hydride as a reaction intermediate, as suggested by the recent detection of formation during open-circuit dissolution. Potential step experiments at pH 11.75 revealed that the potential at the metal–surface film interface was close to the Nernst potential of oxidation. This finding suggested a reaction mechanism in which an interfacial layer is formed continuously by reaction of cathodically formed H with Al, and is then oxidized to the dissolution product, aluminate ions. However, potential step experiments at pH 11 did not indicate the presence of interfacial ; instead, the metal–film interface was close to the equilibrium potential of Al oxidation. Analysis of the CV indicated an abrupt transition in dissolution behavior between the two pH values, from a relatively rapid dissolution controlled by diffusion and film conduction in highly alkaline solutions, to a slow dissolution at a lower pH controlled by a highly resistive surface film. The formation of interfacial occurs readily at the higher pH, but is suppressed as the pH approaches neutrality.
Comments

This article is from Journal of the Electrochemical Society 155 (2008): C189–C195, doi:10.1149/1.2883827. Posted with permission.

Copyright Owner
ECS—The Electrochemical Society
Language
en
File Format
application/pdf
Citation Information
Saikat Adhikari and Kurt R. Hebert. "Participation of Aluminum Hydride in the Anodic Dissolution of Aluminum in Alkaline Solutions" Journal of the Electrochemical Society Vol. 155 Iss. 5 (2008) p. C189 - C195
Available at: http://works.bepress.com/kurtr_hebert/1/