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Development of cerium‐based conversion coatings on 2024‐T3 Al alloy after rare‐earth desmutting
Author(s) -
Hughes A. E.,
Gorman J. D.,
Miller P. R.,
Sexton B. A.,
Paterson P. J. K.,
Taylor R. J.
Publication year - 2004
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.1652
Subject(s) - cerium , intermetallic , x ray photoelectron spectroscopy , conversion coating , auger electron spectroscopy , materials science , oxide , scanning electron microscope , alloy , cerium oxide , metallurgy , dissolution , aluminium , chemistry , chemical engineering , composite material , physics , nuclear physics , engineering
The deposition of Ce‐based conversion coatings onto 2024‐T3 Al alloy sheet was studied using Rutherford backscattering spectroscopy, scanning electron microscopy, Auger electron spectroscopy, x‐ray photoelectron spectroscopy and atomic force microscopy. The Al sheet was pretreated with an alkaline clean followed by treatment in a Ce(IV) and H 2 SO 4 ‐based desmutter. The Ce(IV)‐based conversion coating solution contained 0.1 M CeCl 3 ·7H 2 O and 3% H 2 O 2 and was acidified to pH 1.9 with HCl. Upon immersion, there was an induction period that included activation followed by aluminium oxide growth over the matrix and cerium oxide deposition onto cathodic intermetallic particles and along rolling marks on the surface. After the induction period cerium oxide deposited generally across the whole surface and thickened. The strongest anodic sites initially were adjacent to the intermetallic cathodes and resulted in aluminium dissolution but also oxide thickening. Copyright © 2004 John Wiley & Sons, Ltd.