Abstract

ABD-EL-NABY, B. A. et al. Effect of Alkaline Etching on the Inhibition of the Acidic Corrosion of Aluminum by Lupine Extract. Port. Electrochim. Acta [online]. 2015, vol.33, n.1, pp.1-11. ISSN 0872-1904.  https://doi.org/10.4152/pea.201501001.

The inhibitive effect of Lupine extract on the corrosion of etched and non-etched aluminum in aqueous solution of 0.1 M HCl was investigated at 30 °C by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and optical microscopic techniques. Potentiodynamic polarization curves indicated that Lupine extract acts as anodic type inhibitor. EIS measurements showed that the charge transfer resistance and consequently the inhibition efficiency increase with increasing concentration of Lupine. The experimental data indicated that Lupine is more efficient as inhibitor for the acid corrosion of non-etched aluminum. The inhibitive effect of the extract was assumed to occur via adsorption of active ingredients of the extract on the metal surface. Theoretical fitting of the data to the Kinetic-thermodynamic model were tested to clarify the nature of adsorption. The optical micrographs obtained after surface pre-treatment show that alkaline etching reveals the surface to be porous-like in structure and both the acid and extract have limited effect on the size of pores.

Keywords : corrosion; adsorption; etching; electrochemical techniques; optical microscopy.

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