Title
Modified hydrotalcites for improved corrosion protection of reinforcing steel in concrete – preparation, characterization, and assessment in alkaline chloride solution
Author
Yang, Z.
Fischer, H.
Cerezo, J.
Mol, J.M.C.
Polder, R.
Publication year
2016
Abstract
Six MgAl hydrotalcites (Mg/Al = 2 and 3) were synthesized through the modification of two carbonate hydrotalcites (i.e., Mg(2)AlCO3 and Mg(3)AlCO3) by two amino acids (11aminoundecanoic acid and paminobenzoic acid) and sodium nitrite. They were characterized by means of XRD, FTIR, TG/DSC, and elemental analysis. The ion exchange of the modified hydrotalcites (MHTs) were investigated in alkaline chloride solution and the results showed that ion exchange occurred between free chloride ions and the intercalated inhibitive anions in MHT. The corrosion inhibition of three MHTs (Mg/Al = 2) was evaluated based on the open circuit potential and linear polarization resistance evolution of steel coupons in 0.1 M NaOH solution stepwise enriched with chlorides and the results showed that MHT, in particular, Mg(2)AlpAB exhibited an improved corrosion inhibiting effect in terms of a higher chloride threshold compared to its constituent free inhibitor ions (i.e., pAB). This study confirms the dual protection that MHT, in particular, Mg(2)AlpAB, offers to the steel: capturing chlorides and simultaneously releasing the intercalated inhibitors to further protect the steel from corrosion.
Subject
Nano Technology
MAS - Materials Solutions
TS - Technical Sciences
Chemistry
Industrial Innovation
Amino acids
Chloride-induced corrosion
Corrosion inhibitors
Modified hydrotalcites
Amino acids
Alkaline chlorides
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DOI
https://doi.org/10.1002/maco.201508618
TNO identifier
573074
Publisher
Wiley-VCH Verlag
ISSN
0947-5117
Source
Materials and Corrosion, 67 (7), 721-738
Document type
article