Corrosion Inhibition Performance and Healing Ability of a Hybrid Silane Coating in the Presence of Praseodymium (III) Cations

Abstract

In this study, combinations of two environmentally friendly compounds including a silane-based organic-inorganic coating and a rare earth (RE) salt have been investigated for mitigation of corrosion activity of mild steel. Bilayer silane coatings based on methyl triethoxy silane (MTES) and tetraethyl orthosilicate (TEOS) were reinforced by different amounts of praseodymium cations (Pr3+). The effects of Pr3+ loading on the hydrophobicity and surface properties of the coating were studied by contact angle measurements. Fourier Transform Infrared (FT-IR) spectroscopy was done to scrutinize the curing process and possible structural changes of silane network in the presence of inhibitor. Despite the decrease in the hydrophobic nature of silane coating, the Pr3+ cations did not change the curing of the coating. Electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) measurements confirmed the high corrosion inhibition power for the mild steel sample immersed in 400 ppm Pr3+ containing the saline solution. The results of EIS, polarization and salt spray tests besides the scanning electron microscopy (SEM) images confirmed the silane coating healing ability and corrosion protection properties enhancement in the presence of Pr3+ cations.