A novel corrosion inhibitive system comprising Zn-Al LDH and hybrid sol-gel silane nanocomposite coating for AA2024-T3

A novel layered double hydroxide (LDH)/silane bilayer system was introduced as an effective non-hazardous protective coating for AA2024-T3. Also, the loaded corrosion inhibitors' effect on the bilayer coating system's active anticorrosion properties was studied. For this purpose, diethyldithiocarbamate (DEDTC) molecules, as an eco-friendly corrosion inhibitor, were intercalated in the LDH conversion layer. Furthermore, Ce3+ cations were loaded in the sodium montmorillonite and then incorporated in the mixture of tetraethoxysilane and gamma-amino propyltriethoxysilane. The grazing incidence X-ray diffraction, Fourier-transform infrared spectroscope, and scanning electron microscope (SEM) equipped with energy dispersive spectroscope were used to analyze the structural, surface functional groups, microstructure, and chemical composition of the coatings. Electrochemical impedance spectroscopy, potentiodynamic polarization, and electrochemical current noise technique were employed to investigate the layers' protection behavior. Based on the obtained results, the presence of corrosion inhibitors in the structure of the coatings resulted in a dramatic enhancement in the protection behavior of the substrate. The polarization results illustrated that the corrosion current density of the bilayer system was reduced from 170 to 6.7 nA/cm(2) after employing the corrosion inhibitors into the coating structure. The electrochemical tests and SEM results illustrated the induction of the active anticorrosion properties for the bilayer system containing the DEDTC molecules and Ce3+ cations. The total noise energy for the scratched double-layer coating in the presence and absence of corrosion inhibitors was calculated to be 4.1 and 9.5 pA(2), respectively, indicating efficient corrosion inhibition. (C) 2022 Published by Elsevier B.V.

Automated summary

A novel LDH/silane bilayer system was developed as a non-hazardous protective coating for AA2024-T3. The incorporation of corrosion inhibitors in the coating structure resulted in improved protection behavior, reducing the corrosion current density and inducing active anticorrosion properties. The bilayer system showed efficient corrosion inhibition, as demonstrated by electrochemical tests and SEM results.