Juglans regia L. extract as green inhibitor for stainless steel and aluminium in acidic media

Corrosion inhibition of stainless steel and aluminium with the promising green eco-friendly inhibitor Juglans regia L. was tested in 1 M HCl acidic solution by using various techniques such as gravimetric (weight loss), potentiodynamic polarization and electrochemical impedance spectroscopy. An increase in inhibition efficiency was identified with the increased concentration of the inhibitor, Juglans regia extract, both in water and in ethyl acetate solutions. The inhibition efficiency was found 88.8 % in water solvent for aluminium. For each experiment, water showed better efficiency as a solvent compared to ethyl acetate. It was also realized that the inhibitor molecule had a more positive inhibiting effect on aluminium metal. In addition, the effect of immersion time (2–8 h) was discussed and the adsorption mechanism was fitted with the Langmuir isotherm. Infrared spectra were also employed to discover the changes in functional groups of the organic molecules of the extract.