The effect of zirconium grain refinement on the corrosion behaviour of magnesium-rare earth alloy MEZ

Song G. and StJohn D. (2002) The effect of zirconium grain refinement on the corrosion behaviour of magnesium-rare earth alloy MEZ. Journal of Light Metals, 2 1: 1-16. doi:10.1016/S1471-5317(02)00008-1


Author Song G.
StJohn D.
Title The effect of zirconium grain refinement on the corrosion behaviour of magnesium-rare earth alloy MEZ
Journal name Journal of Light Metals   Check publisher's open access policy
ISSN 1471-5317
Publication date 2002
Sub-type Article (original research)
DOI 10.1016/S1471-5317(02)00008-1
Volume 2
Issue 1
Start page 1
End page 16
Total pages 16
Subject 2500 Materials Science
Abstract Corrosion performance of sand cast magnesium alloy MEZ was investigated for unrefined (MEZU) and Zr-grain-refined (MEZR) microstructures in 5% NaCl solution using salt spray, immersion, in situ examination of the corrosion morphology, ESEM, electron probe microanalysis, hydrogen evolution and polarisation curves. MEZU demonstrated higher rates of anodic dissolution and cathodic hydrogen evolution than MEZR. The central zirconium-rich areas within the grains of the MEZR microstructure was more corrosion resistant than the outer zirconium-depleted areas of the grains, whereas MEZU showed little difference in corrosion between the centre and the edge of the grains. Based on the analyses of the corrosion process, polarisation behaviour and the microstructure of these two alloys, it is postulated that zirconium acts in a number of ways to improve corrosion resistance. Zirconium stabilises the solid solution and makes it inactive in anodic dissolution, significantly passivates the precipitated particles reducing cathodic hydrogen evolution and increases the barrier effect of the grain boundary phase through a finer grain size and thus a more continuous layer of the grain boundary phase.
Keyword Corrosion
Electrochemical tests
Magnesium
Zirconium grain refiner
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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Created: Tue, 05 Jul 2016, 01:32:14 EST by System User