Enhanced active/barrier corrosion protective properties of epoxy coatings containing eco-friendly green inorganic/organic hybrid pigments based on zinc cations/Ferula Asafoetida leaves

In this study, a novel inorganic/organic hybrid pigment based on zinc cations/Ferula Asafoetida leaves extract (Zn-FALE) was synthesized, and its corrosion protection properties were investigated in a saline solution and an organic coating. Interactions of components between Zn2+ cations and FALE were assessed by Thermo-gravimetric analysis (TGA) and ultraviolet-visible (UV-visible) spectroscopy. Corrosion inhibitive performance of FALE and Zn-FALE pigments in the solution phase and coating phase was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). TGA and UV-visible results revealed the proper chela lion between inorganic and organic components of Zn-FALE hybrid green pigments. Electrochemical measurement results showed that the addition of 200 mg L-1 FALE and Zn-FALE in the saline solution increased the total impedance of mild steel plates from similar to 672 to similar to 8154 and 12,786 Omega cm(2), respectively, after 24 h immersion. Also, FALE and Zn-FALE showed a mixed-type inhibition mechanism with an efficiency of 67 and 90.2%, respectively. Moreover, EIS results in the coating phase showed that in the presence of 3 wt% of Zn-FALE pigments, the barrier and active corrosion protection performance of epoxy coatings enhanced significantly. The results showed that Zn-FALE pigments have a better performance compared to other extracts reported in the literature. (C) 2020 Elsevier B.V. All rights reserved.