Synthesis of impregnated Na+-montmorillonite as an eco-friendly inhibitive carrier and its subsequent protective effect on silane coated mild steel

Abstract

Utilization of water-based coatings modified with green active agents is a novel protocol to replace high volatile organic content coatings contained toxic and carcinogenic agents such as hexavalent chromium compounds. So, in the present work, a sol-gel silane coating reinforced with green inhibitive nanocarriers was used to protect steel coupons against 3.5 wt.% NaCl electrolyte. The successful impregnation of montmorillonite (MMT) with the aqueous-based Basil extract as a green corrosion inhibitor was proved by different analyses. Also, the time-dependent release of the green inhibitor from the carriers was proved by UV–vis analysis. The electrochemical studies were done to perceive the protective effect of the green corrosion inhibitor loaded MMT (G-MMT) against steel corrosion in neutral saline solution. The Rct value of G-MMT (10 g/l) was 5 times higher than Additive-free sample, showing the considerable inhibitive action of G-MMT. In the second phase, the beneficial role of G-MMT on the protective behavior of silane coating was shown. The results of surface studies confirmed the precipitation of Basil-containing thin film on the mild steel panels which leads to enhanced corrosion protection behavior of steel coupons. Also, the surface chemical characterization results showed that the formation of Fe2+-inhibitor complex on the surficial active regions was the main inhibitive process in the presence of G-MMT.