An evaluation of Acacia mearnsii tannin as an aluminum corrosion inhibitor in acid, alkaline, and neutral media

The electrochemical behavior of aluminum in tannin from Acacia mearnsii bark was evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in media under three different pH conditions: acid, alkaline, and neutral. A relationship among pH, polymerization grade...

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Bibliographic Details
Published in:Materials and corrosion 2020-07, Vol.71 (7), p.1160-1174
Main Authors: Rodrigues, Silvia R. S., Dalmoro, Viviane, Santos, João H. Z.
Format: Article
Language:English
Subjects:
Aluminum
Bark
corrosion
Corrosion inhibitors
Corrosion mechanisms
EIS
Electrochemical analysis
Electrochemical impedance spectroscopy
Electrode polarization
MALDI–TOF MS
pH effect
tannin
Zeta potential
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Summary:The electrochemical behavior of aluminum in tannin from Acacia mearnsii bark was evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in media under three different pH conditions: acid, alkaline, and neutral. A relationship among pH, polymerization grade (PG), zeta potential, surface, and electrochemical properties was observed in the inhibition performance of the tannin. At high pH, the oligomer structure of the tannin was affected, resulting in a low PG (4) and high zeta potential (−75 mV), and consequently, the inhibition efficiency decreased (68%) in comparison with that in acid (99%) and neutral media (96%). The Δ G a d s 0 values obtained indicate a physisorption mechanism for the aluminum corrosion inhibition in the studied conditions.
ISSN:0947-5117
1521-4176
DOI:10.1002/maco.201911407