Effect of corrosion inhibitor concentration of silane a) b)
films on AA2024-T3 alloy
Célia F. Malfatti1, Tiago L. Menezes1, Ester Rieder2,
1 3 3
Daniel A. Dalla Corte , Julien Esteban , Florence Ansart ,
Jean Pierre Bonino3.
Department of Metallurgy, PPGEM, UFRGS,
91501-970, Porto Alegre, Brazil.
Post-Graduadion Program in Engineering, ULBRA
Laboratoire Chimie des Matériaux Inorganiques et
Energétiques, Université Paul Sabatier - Bat. 2R1 118
Route de Narbonne 31062 Toulouse.
Aluminum and aluminum alloys due to their outstanding
properties, such as low density, high conductivity, easy Fig. 2 – Nyquist (a) and Nyquist (high frequencies) (b)
machining and corrosion resistance, have been diagrams for Al alloy 2024-T3 protected with silane
extensively used in many technological applications, coatings with and without Ce. Diagrams obtained after 24
including car manufacturing, building materials, and hours of immersion in NaCl 0.5 M.
aircraft industry [1,2]. Its use, however, have demanded a) b)
higher corrosion resistance. In this case, recent studies on
the use of silanes as a surface primer to protect against
corrosion have attracted the attention of researchers and
industries. The use of corrosion inhibitors added to silane
has demonstrated a prominent improvement in the
corrosion protection [3,4].
The aim of this work was to study the corrosion behavior
of aluminum alloy AA2024-T3 substrates pre-treated
with 3 glicidoxypropyltrimethoxysilane (GPTMS) silane
layers doped with the different concentrations (0, 0.01
and 0.05 M) of cerium salts. The coatings, obtained by
dip-coating process, were analyzed by scanning electron Fig. 3 – Nyquist (a) and Nyquist (high frequencies) (b)
microscopy – SEM (Fig. 1) and energy dispersive diagrams for Al alloy 2024-T3 protected with silane
spectroscopy (EDS). Electrochemical investigations were coatings with and without Ce. Diagrams obtained after 72
carried out using cyclic voltammetry, open circuit hours of immersion in NaCl 0.5 M.
potential (OCP) and electrochemical impedance
spectroscopy (EIS) measurements.
Fig. 2 and Fig. 3 present the Nyquist diagrams after 72 References
hours of immersion in NaCl 0.5 M solution. The results
show that silane doped with cerium 0.01 M demonstrate 1
higher corrosion resistance, while with higher Yasakau, K.A.; Zheludkevich, M.L.; Karavai, O.V.;
concentration (cerium 0,05 M) the corrosion resistance is Ferreira M.G.S. Progress in Organic Coatings, v. 63, p.
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Tamborim, S.M.; Maisonnave, A.P.Z.; Azambuja, D.S.;
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Substrate: Alloy 5591-6001, 2008.
Pathak, S.S.; Khanna, A.S.; Sinha, T.J.M. Progress in
Organic Coatings, v. 60, p. 211-218, 2007.
Silane Palomino L. M., Suegama P. H., Aoki I. V., Montemor
coating M.F., De Melo H. G. Corrosion Science, Article in Press,
Fig. 1 – SEM of silane coating with containing 0.01M of CNPq, Finep and CAPES.