Table of Contents Author Guidelines Submit a Manuscript
International Journal of Corrosion
Volume 2012, Article ID 452631, 10 pages
http://dx.doi.org/10.1155/2012/452631
Research Article

Corrosion Behaviour of AZ and ZA Magnesium Alloys in Alkaline Chloride Media

1Department of Mechanical Engineering, Dumlupinar University, 43100 Kütahya, Turkey
2Department of Mining, Metallurgical and Materials Engineering, Laval University, Quebec City, QC, Canada G1V 0A6

Received 16 August 2012; Revised 2 November 2012; Accepted 5 November 2012

Academic Editor: Chang-Jian Lin

Copyright © 2012 Mustafa Ö. Öteyaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Corrosion behaviour of AZ and ZA magnesium alloys in untreated, aerated, and deaerated chloride media was investigated. The influence of impurity, alloying element, and oxygen on corrosion potential, rate, and pitting was examined in alkaline media saturated with Mg(OH)2 at pH 9 and 25°C. After 8 h immersion, slightly less active corrosion potentials were generally observed in deaerated than oxygen containing solutions. AZ91D and ZA104 alloys recorded much lower corrosion rates in deaerated medium as compared to AZ91E, ZAC 10403 (0.3Ca), and ZACS1040305 (0.3Ca+ 0.5Sr). Generally, ZAC alloy showed the highest corrosion rate, followed by ZACS alloy, and both showed a constant value in the three media with or without oxygen. The effect of oxygen is then dependent on the alloy properties and is not a simple acceleration of the cathodic reaction but could cause also inhibition and/or passivation. Pit depth and distribution were influenced by alloy composition. The pits were found deeper and more localized on AZ and more uniformly dispersed on ZA alloy surfaces.