The Effect of Post-Treatment Time and Temperature on Cerium-Based Conversion Coatings on Al 2024-T3

Abstract

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.

Department(s)

Materials Science and Engineering

Research Center/Lab(s)

Peaslee Steel Manufacturing Research Center

Keywords and Phrases

Aluminum; Rare Earth Elements; Pitting Corrosion; Oxide Coatings

International Standard Serial Number (ISSN)

0010-938X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2010 Elsevier, All rights reserved.

Publication Date

01 Feb 2010

Link to Full Text

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