Experimental Study of Green Cumin Corrosion Inhibition Properties for Conservation of Copper-Based Archaeological Artifacts

The effect of green cumin extract (Cumin C9H12) on the inhibition of copper-based artifacts from corrosion process was studied. The study examined the protection of copper-based artifacts from corrosion in 3.5% sodium chloride (NaCl) solution at room temperature, with and without different concentrations of green cumin extract as a green inhibitor. Several analyses techniques were used in the study, including gas chromatography was used to characterize in the functional group of the cumin extract. Also,  X-ray fluorescence (XRF), X-ray diffraction and scanning electron microscope attached with energy dispersive spectroscopy, to identify the chemical structure of the experimental coupons and the treated archaeological artifact. The study employed potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and colorimetric measurements to evaluate the efficiency of the cumin corrosion inhibitor. The study concluded that the corrosion inhibition efficacy increases with an increase in green cumin extract concentration. The inhibition efficiency of brass alloys was proven to be 96.33%, which is higher than the 93.89% inhibition efficiency of copper artifacts in 3% neutral media. According to colorimetric measurements, the cumin inhibitor was adsorbed on the metal surface, forming a thin protective layer that reduced corrosion rate.