Abstract
Corrosion performance of sand cast magnesium alloy Mg-RE-Zr after aging treatments at 250 °C was investigated in 3.5% NaCl solution saturated with Mg(OH) 2 ,(pH = 10.5) using potentiodynamic polarization, immersion and auger microscopy. Microstructures have been carried out on Mg-RE-Zr alloy in different thermal states. The central zirconium-rich areas within the grains of the alloy micro structure were more corrosion resistant than the outer zirconium-depleted areas of the grains. Based on the analyses of the corrosion process, polarization behaviors and the microstructure of these alloy, 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.
Original language | English |
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State | Published - 1 Dec 2004 |
Event | European Corrosion Conference: Long Term Prediction and Modelling of Corrosion, EUROCORR 2004 - Nice, France Duration: 12 Sep 2004 → 16 Sep 2004 |
Conference
Conference | European Corrosion Conference: Long Term Prediction and Modelling of Corrosion, EUROCORR 2004 |
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Country/Territory | France |
City | Nice |
Period | 12/09/04 → 16/09/04 |
Keywords
- Corrosion behavior
- Magnesium alloys
- Potentiodynamic polarization
ASJC Scopus subject areas
- Surfaces, Coatings and Films