Surface Processes Accompanying Corrosion-Induced Hydrogen Absorption into Aluminum

Abstract

The role of hydrogen-containing species in the alkaline dissolution of aluminum was studied by secondary ion mass spectrometry (SLMS). Large number densities of submicron particles nucleated and then disappeared during dissolution, at intervals of approximately 3 min. The particles were composed of aluminum hydride, with an aluminum hydroxide surface layer. When particles first appeared, the aluminate ion concentration near the surface was at the solubility of Al(OH)3, and the potential was close to the Nernst potential for oxidation of AlH3 to Al(OH)3. The observed formation of AlH3 indicates that the dissolving Al surface was poised near this equilibrium potential, i. e. that a hydride species serves as an intermediate in the dissolution process.Keywords alkaline dissolution, aluminum hydrides, hydrogen absorption, ion concentrations, surface processing, corrosion, high performance liquid chromatography, aluminum Disciplines Biochemical and Biomolecular Engineering | Biology and Biomimetic Materials CommentsThe archival version of this work was published in S. Adhikari, J. Lee and K. R. Hebert, "Surface Processes Accompanying Corrosion-Induced Hydrogen Absorption into Aluminum," ECS Trans., 3, (31) 173-184 (2007 The role of hydrogen-containing species in the alkaline dissolution of aluminum was studied by secondary ion mass spectrometry (SIMS). Large number densities of submicron particles nucleated and then disappeared during dissolution, at intervals of approximately 3 min. The particles were composed of aluminum hydride, with an aluminum hydroxide surface layer. When particles first appeared, the aluminate ion concentration near the surface was at the solubility of Al(OH) 3 , and the potential was close to the Nernst potential for oxidation of AlH 3 to Al(OH) 3 . The observed formation of AlH 3 indicates that the dissolving Al surface was poised near this equilibrium potential, i. e. that a hydride species serves as an intermediate in the dissolution process.