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The effect of solution temperature and pH on corrosion performance and morphology of nanoceramic‐based conversion thin film
Author(s) -
Mohammadloo H. Eivaz,
Sarabi A. A.,
Alvani A. A. Sabbagh,
Salimi R.,
Sameie H.
Publication year - 2013
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.201106384
Subject(s) - nanoceramic , corrosion , materials science , dielectric spectroscopy , scanning electron microscope , coating , polarization (electrochemistry) , thin film , chemical engineering , conversion coating , composite material , ceramic , metallurgy , electrochemistry , nanotechnology , chemistry , electrode , engineering
In the present study, a nanoceramic hexafluorozirconic acid was used as an eco‐friendly conversion coating, which is free of the conventional phosphate salts. The effect of practical parameters on morphology and corrosion resistance of the coating was studied. Anti‐corrosion behavior of the nanoceramic‐based conversion coating on cold rolled steel substrates was evaluated at different solution pH and temperatures, utilizing the electrochemical impedance spectroscopy and direct current polarization. Moreover, the morphology of thin films was studied using field emission scanning electron microscopy (FE‐SEM). The results revealed that the conversion thin films formed at a dipping temperature of 20 °C and pH 4.5 showed best anti‐corrosion performance. SEM images indicated that increasing solution temperature resulted in micro‐cracks creation and lack of consistency on the surface of the conversion coating. Moreover, the morphological structure changed with increasing pH value.