Corrosion protection of 304L stainless steel by chemical vapour deposited alumina coatings.
Résumé
The corrosion protection of 304L stainless steel by aluminium oxide coatings deposited by metal–organic
chemical vapor deposition (MOCVD) was investigated in a 0.1 M NaCl solution at room temperature by
polarization curves and electrochemical impedance spectroscopy. The effect of the coating thickness
was specifically considered. Transmission electron microscopy cross-section observations of the stainless
steel/alumina coating showed that the coating is amorphous and porosity-free. The impedance response,
for short immersion times, confirmed the absence of porosity and revealed that the alumina coatings
with thickness ranging from 250 nm to 1700 nm provide high corrosion resistance. The corrosion
protection increased when the alumina coating thickness increased. However, from the impedance data
obtained for different exposure times to the aggressive solution, a threshold film thickness of
500–600 nm was determined, above which the corrosion protection was not improved. Due to their
interesting physicochemical properties, such films of amorphous alumina are an innovative and economically
accessible alternative to improve the stainless steel corrosion resistance and could be used in
miniaturized sensors operating in marine environment.
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)
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