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Study of the structure and corrosion behavior of PEO coatings on AM50 maginesium. alloy by electrochemical impedance spectroscopy

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Title Study of the structure and corrosion behavior of PEO coatings on AM50 maginesium. alloy by electrochemical impedance spectroscopy
 
Creator GHASEMI, A
RAJA, VS
BLAWERT, C
DIETZEL, W
KAINER, KU
 
Subject am60 magnesium alloy
anodic films
electrical breakdown
oxidation
titanium
magnesium
electrolyte
plasma electrolytic oxidation
coating
corrosion
 
Description In this work coatings were developed on the surface of AM50 magnesium alloy using four different electrolytes containing 10 wt.% each of K3PO4 and Na3PO4 in combination with either potassium or sodium hydroxides. Electrolyte conductivity and breakdown voltage were measured in order to correlate the property of the coating to the nature of electrolyte. Further, the coatings were examined using scanning electron microscopy for surface morphology and cross sectional investigation, X-ray diffraction for phase determination, and electrochemical impedance spectroscopy for corrosion resistance evaluation. The effect of employing different ions in the electrolytes results in different surface morphologies, chemical phases and, consequently, the corrosion resistance of the coatings. The EIS results indicate the presence of porous and compact layers in the structure of the PEO coatings, whilst the overall coating resistance mainly results from the compact layer, the role of the porous layer as a barrier against corrosion is negligible. Finally, a correlation between the passive current density of the bare alloy and the corrosion resistance of the PEO coating is proposed. (c) 2007 Elsevier B.V .
 
Publisher ELSEVIER SCIENCE SA
 
Date 2011-07-28T21:23:00Z
2011-12-26T12:47:21Z
2011-12-27T05:42:51Z
2011-07-28T21:23:00Z
2011-12-26T12:47:21Z
2011-12-27T05:42:51Z
2008
 
Type Article
 
Identifier SURFACE & COATINGS TECHNOLOGY, 202(15), 3513-3518
0257-8972
http://dx.doi.org/10.1016/j.surfcoat.2007.12.033
http://dspace.library.iitb.ac.in/xmlui/handle/10054/7500
http://hdl.handle.net/10054/7500
 
Language en