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Passivity and Localized Corrosion of AZ31 Magnesium Alloy in High pH Electrolytes

  • Sultan Alsagabi
  • Jakraphan Ninlachart
  • Krishnan S. Raja
  • Indrajit CharitEmail author
Article

Abstract

Electrochemical corrosion tests were carried out on AZ31 magnesium alloy specimens in pH: 4.5, 9.5, and 13.0 solutions with 0-2000 ppm of chloride additions at room temperature. No passivity breakdown was observed during cyclic polarization in pH:13 solutions containing up to 1500 ppm of chloride. Addition of sodium sulfate and sodium dihydrogen phosphate as supporting electrolytes offset the chloride effect on the corrosion of AZ31 in pH 4.5 and 9.5 solutions. The Mott-Schottky analysis showed the presence of a duplex surface layer consisting of an n-type MgO1−x inner layer (x = 0.024-0.05), and a p-type outer layer which thickened with time at the expense of the inner layer.

Keywords

corrosion magnesium wear x-ray 

Notes

Acknowledgment

One of the authors (KSR) acknowledges the support provided by the U.S. Nuclear Regulatory Commission through a faculty development grant NRC-HQ-84-15-G-0025.

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Copyright information

© ASM International 2016

Authors and Affiliations

  • Sultan Alsagabi
    • 1
    • 2
  • Jakraphan Ninlachart
    • 1
  • Krishnan S. Raja
    • 1
  • Indrajit Charit
    • 1
    Email author
  1. 1.Department of Chemical and Materials EngineeringUniversity of IdahoMoscowUSA
  2. 2.Atomic Energy Research InstituteKing Abdulaziz City for Science and TechnologyRiyadhSaudi Arabia

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