Paper Title:

An Innovative Specimen for Mg Corrosion Studies

Periodical Materials Science Forum (Volume 690)
Main Theme Light Metals Technology V
Edited by Hajo Dieringa, Norbert Hort and Karl Ulrich Kainer
Pages 365-368
DOI 10.4028/www.scientific.net/MSF.690.365
Citation Zhi Ming Shi et al., 2011, Materials Science Forum, 690, 365
Online since June, 2011
Authors Zhi Ming Shi, Andrej Atrens
Keywords Crevice Corrosion, Magnesium, Polarisation, Scanning Electron Microscope (SEM), Weight Loss
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Abstract

Plug-in specimens enable measurement of reliable Mg polarization curves. Cathodic polarization curves were measured for high purity Mg in 3.5% NaCl saturated with Mg(OH)2 using (i) mounted specimens and (ii) plug-in specimens. Polarization curves yielded the corrosion current density icorr and the corresponding corrosion rate Pi, which was compared with corrosion rates evaluated from hydrogen evolution, PH, and weight loss, PW. Mounted specimens produce Pi values three times larger than plug-in specimens, due to crevice corrosion in the mounted specimens. Plug-in specimens had no crevice and allow simultaneous measurement of PH and Pi. Pi was less than PH and indicated an apparent valence of 1.45 in support of the existence of the uni-positive Mg+ ion.