Journal of Applied Electrochemistry

, Volume 38, Issue 11, pp 1589–1598

Role of alloyed silicon and some inorganic inhibitors in the inhibition of meta-stable and stable pitting of Al in perchlorate solutions

  • Mohammed A. Amin
  • Hamdy H. Hassan
  • Omar A. Hazzazi
  • Mohsen M. Qhatani
Original Paper

DOI: 10.1007/s10800-008-9600-9

Cite this article as:
Amin, M.A., Hassan, H.H., Hazzazi, O.A. et al. J Appl Electrochem (2008) 38: 1589. doi:10.1007/s10800-008-9600-9

Abstract

The study of both meta-stable and stable pitting events on the surface of pure Al and three Al–Si alloys, namely (Al + 6%Si), (Al + 12%Si) and (Al + 18%Si) alloys, was carried out in deaerated neutral NaClO4 solutions of various concentrations (10−4–10−2 M). Measurements were carried out under the effect of various experimental conditions using potentiodynamic anodic polarization and potentiostatic techniques. The results presented below showed that meta-stable pits (appeared as oscillations in current) form at potentials close to the pitting potential (Epit) and during the induction time for stable pit formation. Various factors affecting the rate of meta-stable and stable pits were studied. The presence of Si as an alloying element in Al reduces the rate of formation of meta-stable pits, corresponding to a reduction in the probability of developing stable pits, and an increase in the pitting potential results. The inhibitive effects of chromate, silicate, molybdate and tungstate on pitting corrosion in Al were also studied. Results obtained showed that these known inhibitors retard both meta-stable and stable pitting events. This makes attainment of stable pit growth more difficult in presence of these inhibitors.

Keywords

Pitting corrosionMeta-stable and stable pitsAlAl–Si alloysSodium perchlorate solutionsInorganic inhibitors

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Mohammed A. Amin
    • 1
    • 2
  • Hamdy H. Hassan
    • 1
    • 3
  • Omar A. Hazzazi
    • 4
  • Mohsen M. Qhatani
    • 2
  1. 1.Faculty of Science, Department of ChemistryAin Shams UniversityCairoEgypt
  2. 2.Materials and Corrosion Lab (MCL), Faculty of Science, Department of ChemistryTaif UniversityTaifSaudi Arabia
  3. 3.Faculty of Science, Department of ChemistryKing Khalid UniversityAbhaSaudi Arabia
  4. 4.Faculty of Applied Science, Department of ChemistryUmm Al-Qura UniversityMakkahSaudi Arabia