Hydrogen in aluminum during alkaline corrosion

TitleHydrogen in aluminum during alkaline corrosion
Publication TypeJournal Article
Year of Publication2010
AuthorsAdhikari S, Ai JH, Hebert KR, Ho KM, Wang CZ
Journal TitleElectrochimica Acta
Volume55
Pages5326-5331
Date Published7/30
ISBN Number0013-4686
Accession NumberISI:000280018800007
Keywordsadsorption, aluminum, corrosion, diffusion, electrode, HYDRIDE, hydrogen absorption, hydrogen chemical potential, hydrogen diffusion, metals, palladium, permeation, PH, system
Abstract

The thermodynamic state of hydrogen in aluminum during alkaline corrosion was investigated, using a two-compartment hydrogen permeation cell with an Al/Pd bilayer membrane. The open-circuit potential of the Pd layer in a pH 7.0 buffer solution was monitored to sense the hydrogen chemical potential, pH. At pH 12.5-13.5, the measurements established a minimum pH of 0.55 eV relative to the ideal gas reference, equivalent to a H-2 gas pressure of 5.7 GPa. Statistical mechanics calculations show that vacancy-hydrogen defects are stable in Al at this condition. A dissolution mechanism was proposed in which H at very high pH is produced by oxidation of interfacial aluminum hydride. The mechanism explains the observed rapid accumulation of H in the metal by extensive formation of vacancy-hydrogen defects. (C) 2010 Elsevier Ltd. All rights reserved.

URL<Go to ISI>://000280018800007
DOIDoi 10.1016/J.Electacta.2010.04.076