Potency of ZnFe2O4 Nanoparticles as Corrosion Inhibitor for Stainless Steel; the Pigment Extract Study

The corrosion inhibition of nanoparticulates zinc ferrite (NZF) pigment was studied. The steel samples were immersed in the NZF pigment extract in 3.5 wt. % NaCl. Electrochemical tests such as electrochemical impedance spectroscopy (EIS) and polarization as well as surface analysis were employed to evaluate the effect of NZF on the steel corrosion. The concentration of Zn and Fe in the pigment extracts before and after immersion of mild steel samples was evaluated by inductively coupled plasma-optical emission spectrometry (ICP-OES). EIS results in total agreement with results of polarization test demonstrated superiority of NZF as an anticorrosion pigment. In the case of samples exposed to NZF extract, the higher resistance and lower double layer capacitance extracted from impedance spectra as well as lower current density from polarization results might be attributed to precipitation of an inhibitive layer on the surface. This was also supported by SEM/EDS and ICP-OES results.