An exploratory study of the corrosion of Mg alloys during interrupted salt spray testing

Zhao, M.C., Schmutz, P., Brunner, S., Liu, M., Song, G.L. and Atrens, A. (2009) An exploratory study of the corrosion of Mg alloys during interrupted salt spray testing. Corrosion Science, 51 6: 1277-1292. doi:10.1016/j.corsci.2009.03.014


Author Zhao, M.C.
Schmutz, P.
Brunner, S.
Liu, M.
Song, G.L.
Atrens, A.
Title An exploratory study of the corrosion of Mg alloys during interrupted salt spray testing
Journal name Corrosion Science   Check publisher's open access policy
ISSN 0010-938X
Publication date 2009-06-01
Year available 2009
Sub-type Article (original research)
DOI 10.1016/j.corsci.2009.03.014
Open Access Status DOI
Volume 51
Issue 6
Start page 1277
End page 1292
Total pages 16
Editor Burstein, G.T.
Place of publication United Kingdom
Publisher Pergamon
Language eng
Subject C1
8612 Fabricated Metal Products
0912 Materials Engineering
Abstract A first systematic investigation was carried out to understand the corrosion of common Mg alloys (Pure Mg, AZ31, AZ91, AM30, AM60, ZE41) exposed to interrupted salt spray. The corrosion rates were also evaluated for these alloys immersed in 3 wt.% NaCl by measuring hydrogen evolution and an attempt was made to estimate the corrosion rate using Tafel extrapolation of the cathodic branch of the polarisation curve. The corrosion of these alloys immersed in the 3 wt.% NaCl solution was controlled by the following factors: (i) the composition of the alpha-Mg matrix, (ii) the volume fraction of second phase and (iii) the electrochemical properties of the second phase. The Mg(OH)(2) surface film on Mg alloys is probably formed by a precipitation reaction when the Mg(2+) ion concentration at the corroding surface exceeds the solubility limit. Improvements are suggested to the interrupted salt spray testing; the ideal test cycle would be a salt spray of duration X min followed by a drying period of (120-X) min. Appropriate apparatus changes are suggested to achieve 20% RH rapidly within several minutes after the end of the salt spray and to maintain the RH at this level during the non-spray part of the cycle. The electrochemical measurements of the corrosion rate, based oil the "corrosion current" at the free corrosion potential, did not agree with direct measurements evaluated from the evolved hydrogen, in agreement with other observations for Mg. (C) 2009 Elsevier Ltd. All rights reserved.
Keyword Magnesium
CALCULATED PHASE-DIAGRAMS
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Mechanical & Mining Engineering Publications
ERA 2012 Admin Only
 
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Created: Thu, 03 Sep 2009, 17:56:18 EST by Mr Andrew Martlew on behalf of School of Mechanical and Mining Engineering