Eco-Friendly Roselle (Hibiscus Sabdariffa) Leaf Extract as Naturally Corrosion Inhibitor for Cu-Zn Alloy in 1M HNO3

The eco-friendly compounds especially plant extracts have emerged as great green corrosion inhibitors for metals and alloys. The inhibiting impact of Roselle extract on Cu-Zn alloy in 1M HNO3 solution was studied by weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). It was found that Roselle extract acts as a good mixed-type corrosion inhibitor for Cu-Zn alloy in acid solution. The corrosion rate decreases with increasing the extract concentration and increases with raising the temperature. The formation of a protecting film on the Cu-Zn alloy surface with the presence of Roselle extract was shown and confirmed by scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX). The high inhibition efficiency of 94.89 % was recorded for 80% extract solution. There are good agreements between the results from all techniques.