The Effect of Post-treatment Time and Temperature on Cerium-based Conversion Coatings on Al 2024-T3
Corrosion performance, morphology, and electrochemical characteristics of cerium-based conversion coatings on Al 2024-T3 were examined as a function of phosphate post-treatment time and temperature. Corrosion resistance improved after post-treatment in 2.5 wt.% NH4H2PO4 for times up to 10 min or temperatures up to 85 °C. Electrochemical impedance spectroscopy and polarization testing correlated to neutral salt spray corrosion performance. Hydrated cerium oxide and peroxide species present in the as-deposited coatings were transformed to CePO4·H2O for post-treatments at longer times and/or higher temperatures. Based on these results, processes active during post-treatment are kinetically dependent and strongly influenced by the post-treatment time and temperature.
D. K. Heller et al., "The Effect of Post-treatment Time and Temperature on Cerium-based Conversion Coatings on Al 2024-T3," Corrosion Science, Elsevier, Feb 2010.
The definitive version is available at http://dx.doi.org/10.1016/j.corsci.2009.09.023
Materials Science and Engineering
Keywords and Phrases
Aluminum; Rare Earth Elements; Pitting Corrosion; Oxide Coatings
Article - Journal
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