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Effects of NH 4 + , Na + , and Mg 2+ ions on the corrosion behavior of galvanized steel in wet–dry cyclic conditions
Author(s) -
Neupane Shova,
Hastuty Sri,
Yadav Neelima,
Singh Nilima,
Gupta Dipak K.,
Yadav Brahamdeo,
Singh Sanjay,
Karki Nabin,
Kumari Das Anju,
Subedi Vivek,
Nakarmi Krishna B.,
Yadav Amar P.
Publication year - 2021
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.202112360
Subject(s) - corrosion , ion , chemistry , relative humidity , anode , galvanization , inorganic chemistry , nuclear chemistry , polarization (electrochemistry) , materials science , metallurgy , layer (electronics) , electrode , physics , organic chemistry , thermodynamics
The effect of cations on the corrosion of galvanized steel (GS) is scarcely reported. In this study, a wet–dry cyclic test was conducted to study NH 4 + , Na + , and Mg 2+ cation effect on the corrosion behavior of GS available in Nepal. Fourteen wet–dry cycles (18 h wet and 6 h dry) were performed by exposing samples at 298 K with a relative humidity of 90% in a wet cycle and 50% in a dry cycle for 14 days. The cations strongly affect the corrosion rate of the GS sample estimated by weight loss and potentiodynamic polarization. The potentiodynamic polarization curves showed the inhibition of cathodic and anodic reactions by Mg 2+ ion, while the NH 4 + ion only changed the cathodic reaction. Mg 2+ ion was found to shift the corrosion potential to noble values compared with NH 4 + and Na + ions. A compact and thin corrosion products layer was developed in Mg 2+ salt solution in contrast to a thick and porous corrosion products layer in NH 4 + and Na + salt solutions. Red rust due to corrosion of underlying steel appeared in the presence of NH 4 + and Na + salt solutions. Finally, the weight loss data revealed that the corrosivity of cations for GS decreased in the order Na + > NH 4 + > Mg 2+ .