Issue 2, 2016

The effect of iron re-deposition on the corrosion of impurity-containing magnesium

Abstract

This article provides a contribution towards the mechanistic understanding of surface phenomena observed during the corrosion of Mg-based substrates particularly in the low anodic polarization range. The concept considers the recent literature explaining cathodic hydrogen evolution from noble acting areas even during global anodic polarization. Heavy metal impurities in the ppm range or intermetallics are always present even in highly pure magnesium. Their potential effect was investigated here in more detail. The experimental results contribute to understanding the role of iron impurities in dark area formation and suggest a way for linking the observed phenomena to the recent literature. The shown enhanced cathodic activity of dark areas especially at the corrosion front and the superfluous hydrogen are linked to an iron re-deposition mechanism due to iron reduction. The proposed mechanism is based on the results obtained from innovative characterisation techniques using magnetic fields, diffraction experiments and transmission electron microscopy, which show the formation of iron rich zones, especially at the corrosion front offering “in statu nascendi” metallic Fe films acting as active cathodes for hydrogen reduction.

Graphical abstract: The effect of iron re-deposition on the corrosion of impurity-containing magnesium

Article information

Article type
Paper
Submitted
17 set 2015
Accepted
20 nov 2015
First published
26 nov 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2016,18, 1279-1291

Author version available

The effect of iron re-deposition on the corrosion of impurity-containing magnesium

D. Höche, C. Blawert, S. V. Lamaka, N. Scharnagl, C. Mendis and M. L. Zheludkevich, Phys. Chem. Chem. Phys., 2016, 18, 1279 DOI: 10.1039/C5CP05577F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements