Effect of ca addition on corrosion behavior of wrought am60 magnesium alloy in alkaline solutions

Polina Metalnikov, Guy Ben‐hamu, Kwang Seon Shin, Amir Eliezer

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Magnesium (Mg) alloys possess the lowest density among structural materials, and their application in the automotive and aircraft industries might enhance fuel efficiency. The mechanical properties can be improved by the addition of alloying elements. However, since Mg and its alloys are very susceptible to corrosion degradation, it is important to study the effect of these elements on the alloys’ corrosion behavior. In this study, 1 wt% of calcium (Ca) was added to wrought AM60 Mg alloy, and the electrochemical corrosion behavior of the alloys in alkaline solutions with and without Cl ions was compared. The corrosion behavior was investigated by means of immersion tests, gravimetric measurements and potentiodynamic polarization (PDP); the characteristics of the oxide layer were studied by electrochemical impedance spectroscopy (EIS) and X‐ray photoelectron spectroscopy (XPS). The addition of Ca resulted in precipitation of the ternary aluminum‐rich (Mg‐ Al)2Ca phase. Scanning Kelvin probe force microscope (SKPFM) identified that this phase has a cathodic behavior relative to the α‐Mg matrix; hence it can serve as additional sites for initiation of pitting corrosion. As a result, the corrosion resistance of wrought AM60 alloy with 1 wt% Ca addition deteriorated in a NaCl solution. However, in the absence of Cl ions, alloying with Ca improves the corrosion resistance of wrought AM60 alloy due to the stabilization of the corrosion products layer. The effect of long‐period immersion time on the corrosion behavior and alloy oxidation is discussed.

Original languageEnglish
Article number1172
JournalMetals
Volume11
Issue number8
DOIs
StatePublished - 1 Aug 2021

Keywords

  • Calcium addition
  • Corrosion resistance
  • Magnesium
  • Oxide layer

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