This study focuses on the synthesis of lithium-exchange silica (Si/Li) particles and their corrosion protection for aluminum alloy substrates. Silica is synthesized via a sol-gel method as a raw material to prepare Si/Li in a saturated lithium nitrate solution. The obtained samples are characterized by X-ray diffraction, field emission scanning electron microscopy, zeta potential measurements, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectroscopy. Inhibition properties of synthesized Si/Li are investigated by electrochemical impedance spectroscopy (EIS). The results show that Si/Li prepared in the saturated lithium nitrate solution has a high content of loaded lithium. This amount relates to a high and stable corrosion protection of Si/Li in the electrolyte solution for the aluminum alloy substrate. After 96 h of immersion in the electrolyte solution, electrochemical results show a high value of an inhibition efficiency up to 98%. Water-based epoxy coatings containing Si/Li are also prepared to highlight their corrosion protection efficiency for the aluminum alloy substrate. Concerning the EIS measurement results, the coating containing 5 wt% Si/Li shows high and stable barrier properties for a long immersion time in the protection of the aluminum alloy substrate.

This study presents the inhibitive property of Co(II) ions in the corrosion protection of commercial hot-dip galvanized steel in aggressive solution. The polarization measurements reveal the action of Co(II) cations in the anodic branch with the inhibitive efficiency determined at 96% for 0.01 M of Co(II). The corrosion resistance was reinforced by a passive layer formed at Zn surface, that was assessed by the electrochemical measurements. The existence and the crystal structure of this protective layer was analyzed by field-emission scanning electron microscopy observations. X-ray diffraction analysis was confirmed the formation of zinc cobalt hydroxide and cobalt zinc oxide on the Zn surface that attributed to the inhibitive action of the Co cations.