Anodization of AZ91D magnesium alloy in silicate-containing electrolytes

Houng Yu Hsiao, Hua Chih Tsung, Wen-Ta Tsai

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131 Citations (Scopus)


The effects of Al(NO3)3 and/or Na2 SiO3 additions in the anodizing electrolyte on the properties of the anodic films formed on AZ91D magnesium alloy were investigated. The base electrolyte used in this investigation was 3 M KOH+0.21 M Na3PO4+0.6 M KF solution. The crystal structure, chemical state, surface morphology and cross-section microstructure of the anodic film was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The corrosion behavior of anodized Mg alloy is examined using electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. The results show that the anodic film was mainly composed of MgO. The additions of Na2SiO3 and/or 0.15 M Al (NO3)3 into to the base electrolyte enhanced the formations of Al2O3, MgAl2O4 in the silicate-containing anodized film, accompanied with silicate formation. Increased corrosion resistance of the anodic film was found when AZ91D Mg alloy was anodized in 3 M KOH+0.21 M Na3 PO4+0.6 M KF+0.15 M Al(NO3)3 with 0.1 M Na2SiO3 addition.

Original languageEnglish
Pages (from-to)127-134
Number of pages8
JournalSurface and Coatings Technology
Issue number2-3 SPEC. ISS.
Publication statusPublished - 2005 Sep 22

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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