Corrosion behaviour of Mg/Al alloys with composite coatings
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2009
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Elsevier
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A. Pardo, M.C. Merino, M. Mohedano, P. Casajús, A.E. Coy, R. Arrabal, Corrosion behaviour of Mg/Al alloys with composite coatings, Surface and Coatings Technology, Volume 203, Issue 9, 2009, Pages 1252-1263, ISSN 0257-8972, https://doi.org/10.1016/j.surfcoat.2008.10.030.
Abstract
The corrosion behaviour of aluminium/silicon carbide (Al/SiC) composite coatings deposited by thermal spray on AZ31, AZ80 and AZ91D magnesium-aluminium alloys was investigated by electrochemical and gravimetric measurements in 3.5 wt.% NaCl solution at 22 °C. Corrosion products were examined by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and low-angle X-ray diffraction (XRD). Al/SiC composite coatings in the as-sprayed state revealed high level of porosity with poor bonding at the Al/SiC and coating/substrate interfaces, which facilitated degradation of the magnesium substrates by a mechanism of galvanic corrosion. Cold-pressing post-treatment produced more compact coatings with improved corrosion performance in 3.5 wt.% NaCl compared with as-sprayed coatings.