In situ kinetics studies of Zn-Al LDH intercalation with corrosion related species.

Kinetic parameters for three anion exchange reactions - Zn-LDH-NO→ Zn-LDH-Cl, Zn-LDH-NO→ Zn-LDH-SO and Zn-LDH-NO→ Zn-LDH-VO- were obtained by in situ synchrotron study. The first and the second ones are two-stage reactions; the first stage is characterized by the two-dimensional diffusion-controlled reaction following deceleratory nucleation and the second stage is a one-dimensional diffusion-controlled reaction also with a decelerator nucleation effect. In the case of exchange NO→ Cl host anions are completely released, while in the case of NO→ SO the reaction ends without complete release of nitrate anions.

One-step synthesis and growth mechanism of nitrate intercalated ZnAl LDH conversion coatings on zinc.

An approach for the synthesis of ZnAl-NO3 LDH conversion coatings on zinc in an aqueous acidic Al(NO3)3/NaNO3 solution is demonstrated for the first time. The growth mechanism has been investigated using time resolved structural, microstructural and analytical methods. A LDH growth model involving both electrochemical and chemical processes is suggested.