Electrochemical corrosion studies of thixomolded AZ91D alloy in sodium chloride solution

Isao Nakatsugawa*, Hidenori Takayasu, Katsuyuki Araki, Tadayoshi Tsukeda

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

8 Scopus citations

Abstract

The influence of chloride ion concentration on the corrosion behavior of thixomolded AZ91D alloy under anodic polarization and natural immersion into sodium chloride solution was investigated. A small passivation following its breakdown at critical potential was observed on anodic polarization curves. The critical potential showed a linear relationship with square root of scanning rate and logarithm of sodium chloride concentration. In natural immersion condition, electrochemical noise at corrosion potential and an inductive loop on the impedance diagram appeared after certain period. Those behaviors indicated the start of depassivation which would bring about filiform corrosion and pitting in later stage. The critical concentration of depassivation was estimated to around 10-2 kmol/m3. If it was lower than this value, the corrosion rate showed a constant value around 7 mg/m2/h (0.03 mm/y).

Original languageEnglish
Pages (from-to)845-850
Number of pages6
JournalMaterials Science Forum
Volume419-422
Issue numberII
DOIs
StatePublished - 2003
EventProceedings of the Second Osaka International Conference on Platform Science and Technology for Advanced Magnesium Alloys 2003 - Osaka, Japan
Duration: 2003/01/262003/01/30

Keywords

  • Corrosion
  • Electrochemistry
  • Impedance spectroscopy
  • Magnesium alloy
  • Passivation

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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