BENDINELLI, E.V. ; AOKI, I.V. ; BARCIA, O. ; Margarit-Mattos, I.C.P. .
Resumo: The objective is to study the influence of Mg–Al layered double hydroxides (LDHs) reconstruction processes on inhibitor release kinetics and anion exchange properties, emphasizing the importance of the knowledge of these physicochemical properties to manage and optimize intelligent corrosion protective action. LDHs were prepared using two reconstruction methods after hydrotalcite (HT) calcination: i) reconstruction in terephthalic acid (HTCTe), followed by substitution of terephthalate by imidazole (HTCTe-Im) and ii) direct reconstruction in imidazole solution (HTC-Im). Imidazole (Im) is a film-forming corrosion inhibitor that was selected due to its molecule features. XRD showed that terephthalate and Im did not influence network parameters of reconstructed LDHs, but HTC-Im presented better crystallinity. Such difference strongly influence the kinetics of Im release and anion exchange process of the two LDHs. Similar corrosion inhibition efficiencies were measured for both particles by weight loss. However, localized corrosion was evidenced for HTC-Im. It was notable the synergistic effect of HTC-Im and HTCTe-Im mixtures due to the large amount of imidazole released by HTCTe-Im and removal of chloride from solution by HTC-Im. Results also suggested an active role of LDH itself on corrosion inhibition, attributed to pH and solubilization of structural components other than Im.
