Zn-Al-NO_2 layered double hydroxide as a controlled-release corrosion inhibitor for steel reinforcements

摘要

Zn-Al-NO2 layered double hydroxide (LDH) is proposed as a controlled-release inhibitor for steel reinforcements in chloride-contaminated concrete. The cumulative amount of nitrite released from LDH is sensitive to the chloride concentration in the solution. Compared with NaNO2, Zn-Al-NO2 LDH increased the chloride threshold value from 0.15 to 0.25 M and simultaneously decreased the critical [NO2]/[Cl] molar ratio from 0.09 to 0.02. In conclusion, the Zn-Al-NO2 LDH exhibits considerably higher inhibiting performance due to the on-demand release of NO2-. (C) 2018 Elsevier B.V. All rights reserved.