Experimental and modeling studies of single pits on pure aluminum in pH 11 NaCl solutions I. Laser initiated single pits

Marta Verhoff, Richard Alkire

Research output: Contribution to journalArticlepeer-review


The anodic dissolution of pure aluminum in pH 11 chloride media was investigated. Individual hemispherical corrosion pits were produced by a laser initiation technique, and electrochemical measurements were analyzed to determine the effect of diffusion and migration on single pit growth. Several mathematical models, which included both migration and diffusion as transport modes, were developed to interpret experimental results and to predict concentration profiles that resulted from dissolution based on the assumption of a hemispherical corrosion pit geometry. Model equations were solved by a quasi-potential transformation technique. The results for a model that considered a simple case of three ionic species demonstrated that it was essential to include both migration and diffusion phenomena in the model, contrary to previous experimental studies that concluded that pit dissolution was controlled by diffusion only. The results of a more advanced model that included two hydrolysis reactions for aluminum predicted a pH (<3.5 in 90% of the computational domain) that was in good agreement with experimental data (pH 3-4). The addition of the hydrolysis reactions had no effect on the concentration profiles of the three species considered in the simple chemistry model. Models that included homogeneous reactions to test the hypothesis of formation of an aluminum oxychloride salt [Al(OH)2Cl] predicted a pH ≥ 5, and also that the concentration of the salt was significantly smaller than the estimated saturation concentration of 3 mol/L.

Original languageEnglish (US)
Pages (from-to)1349-1358
Number of pages10
JournalJournal of the Electrochemical Society
Issue number4
StatePublished - Apr 2000

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Renewable Energy, Sustainability and the Environment


Dive into the research topics of 'Experimental and modeling studies of single pits on pure aluminum in pH 11 NaCl solutions I. Laser initiated single pits'. Together they form a unique fingerprint.

Cite this