Corrosion behaviour of Sn-containing oxide layer on AZ91D alloy formed by plasma electrolytic oxidation

Corrosion phenomenon of magnesium alloys is one of the limits for using magnesium alloys in automotive and aerospace industries. The aim of this study is the development of Sn-containing protective oxide coating by a simple plasma electrolytic oxidation in KOH/KF/Na 3PO 4 electrolyte on AZ91D magnes...

Full description

Saved in:
Bibliographic Details
Published in:Surface & coatings technology 2008-05, Vol.202 (17), p.4145-4152
Main Authors: Barchiche, C.-E., Rocca, E., Hazan, J.
Format: Article
Language:English
Subjects:
Anodic film
Applied sciences
AZ91D magnesium alloy
Corrosion
Corrosion environments
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Materials science
Metals. Metallurgy
PEO
Physics
Stannate
Surface treatments
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Corrosion phenomenon of magnesium alloys is one of the limits for using magnesium alloys in automotive and aerospace industries. The aim of this study is the development of Sn-containing protective oxide coating by a simple plasma electrolytic oxidation in KOH/KF/Na 3PO 4 electrolyte on AZ91D magnesium alloy in galvanostatic mode. The film morphology and composition were analysed by SEM coupled with EDS, XRD and Raman spectroscopy. In the oxide, tin is mainly incorporated as crystallised MgSn(OH) 6 compound in the layer. The main properties of Sn-containing oxide coating on AZ91D are both keeping the corrosion rate at open-circuit conditions at an acceptable value, and providing a sufficient passivation plateau to reduce the pitting sensibility. The lather characteristic, revealed by pitting tests, addresses the major drawback of magnesium alloys which often undergo important galvanic coupling in service. Consequently, the addition of low stannate concentration in the electrolyte to form Sn-rich anodic oxide on magnesium alloys represents an interesting way to synthesize protective coatings by PEO in a short time of anodization.
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2008.03.010