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Microstructural characteristics and corrosion behavior of cerium oxide conversion coatings on AA6063
Author(s) -
Kanani M.,
Danaee I.,
Maddahy M. H.
Publication year - 2014
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201307539
Subject(s) - dielectric spectroscopy , corrosion , materials science , cerium , scanning electron microscope , cerium oxide , conversion coating , oxide , alloy , coating , metallurgy , polarization (electrochemistry) , aluminium , chemical engineering , energy dispersive x ray spectroscopy , electrochemistry , composite material , electrode , chemistry , engineering
Cerium‐based conversion coating was deposited on aluminum 6063 and its corrosion behavior was studied. Corrosion resistance was investigated at different pH in 3.5 wt% NaCl solution by means of electrochemical impedance spectroscopy, potentiodynamic polarization, and surface techniques. The coated samples showed a significant decrease in corrosion rate. The coating obtained by 600 s immersion covers uniformly the alloy surface. Electrochemical impedance data shows that with increasing immersion time, the charge transfer resistance of aluminum increased. Surface morphology and its chemical composition were analyzed by means of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). SEM images in agreement with the electrochemical results indicated that aluminum surface was not completely covered after short immersion time. The EDS analysis confirmed the presence of cerium oxide on the aluminum surface and the cerium content was increased with increasing immersion time.