Effects of Acid and Alkaline based Surface Preparations on Spray Deposited Cerium based Conversion Coatings on Al 2024-T3

Abstract

Cerium based conversion coatings were spray deposited on Al 2024-T3 and characterized to determine the effect of surface preparation on the deposition rate and surface morphology. It was found that activation of the panel using a 1-wt.% sulfuric acid solution increased the coating deposition rate compared to alkaline cleaning alone. Analysis of the surface morphology of the coatings showed that the coatings deposited on the acid treated panels exhibited fewer visible cracks compared to coatings on alkaline cleaned panels. Auger electron spectroscopy depth profiling showed that the acid activation decreased the thickness of the aluminum oxide layer and the concentration of magnesium on the surface of the panels compared to the alkaline treatment. Additionally, acid activation increased the copper concentration at the surface of the aluminum substrate. Based on the results, the acid based surface treatment appeared to expose copper rich intermetallics, thus increasing the number of cathodic sites on the surface, which led to an overall increase in the deposition rate.

Department(s)

Materials Science and Engineering

Research Center/Lab(s)

Peaslee Steel Manufacturing Research Center

Sponsor(s)

Strategic Environmental Research and Development Program (U.S.)

Keywords and Phrases

Aluminum 2024-T3; Cerium Conversion Coating; Coatings; Corrosion; Surface Preparation

International Standard Serial Number (ISSN)

0169-4332

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2009 Elsevier, All rights reserved.

Publication Date

01 Jan 2009

Link to Full Text

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