To modify the corrosion protection provided by conversion coated Zn-Al-CO3 layered double hydroxides (LDHs) on electrogalvanized steel sheets (EG steels), methods to intercalate NO3- during post treatment were explored and the effect of intercalation on corrosion resistance was evaluated. EG steels were immersed in a Na-2 Al2O4 based solution to form a Zn-Al-CO3 LDH conversion coating layer, and were then immersed in a NaNO3 methanol solvent to intercalate NO3-. After 2 h of immersion, it was found that NO3- had completely exchanged with the originally intercalated CO32- anions in the conversion coated Zn-Al-CO3 LDHs. Corrosion resistance measurements of the EG steel surfaces protected by the NO3- intercalated in the LDH layer were performed by a simple immersion test and a droplet test. When the samples were immersed in a large amount of 0.1 M NaCl, the corrosion resistance of the NO3- intercalated LDH layer was inferior to that of the control sample. In contrast, the samples that were exposed to a 100 mu l droplet of 0.1 M NaCl displayed improved corrosion resistance. The difference in these results was attributed to the solubility of the LDH layer and the resulting effect on the release process of NO3- from the LDH layer. (C) The Author(s) 2018. Published by ECS.