Cerium-based conversion coatings were deposited on as-cast aluminum alloy 380 substrates by a spontaneous immersion process. In this study, the effects of rinsing temperature prior to immersion in the coating deposition solution were studied with respect to the surface morphology, electrochemical response, and corrosion resistance of the coatings. Panels rinsed at 25 degrees celsius prior to coating had large cracks and holes in the coating. In contrast, panels rinsed at 100 degrees celsius prior to coating had a uniform coating morphology with fewer, smaller cracks. Electrochemical testing revealed that coatings deposited on substrates rinsed at 100 degrees celsius had higher impedance (~80kilo-ohms*cm^2) and lower corrosion current (~0.34nu*A/cm^2) compared to coatings deposited on substrates rinsed at 25 degrees celsius which had 10 kilo-ohms impedance and 2.7 nu*A/cm^2 corrosion current. Finally ASTM B117 salt spray testing showed that rinsing at 100 degrees celsius prior to coating resulted in cerium-based conversion coatings that could resist the formation of salt tails for at least 8 days.
C. Lin et al., "Deposition of Cerium-based Conversion Coatings on Aluminum Alloy 380," International Journal of Corrosion, Hidawi Publishing, Jan 2012.
The definitive version is available at https://doi.org/10.1155/2012/760284
Materials Science and Engineering
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