Influence of different polyphenol extracts of Taxus baccata on the corrosion process and their effect as additives in electrodeposition

Abstract

The corrosion inhibition of carbon steel in 1 M HCl solution by methylene dichloride (MDE), ethyl acetate (EAE) and butanolic (BE) extracts of Taxus baccata and the evaluation of their behaviours as additives in electroplating were studied. Potentiodynamics polarization, electrochemical impedance spectroscopy (EIS), weight loss meseurment and scanning electron microscopy (SEM) methodes were employed for this investigation. The experimental results indicate that all tested extracts exhibited a good corrosion inhibition reaching values of 79%, 82% and 74% for MDE, EAE and BE respectively. However, the protection efficiency decreased whil temperature goes up. The polarization curves showed that MDE, EAE and BE acted as mixed type inhibitors. The free adsorption energies of the extracts vary from (−23 KJ/mol) to (−19 KJ/mol) revealed a spontaneous physical adsorbtion on the steel surface following Langmuir isotherm. The electrodeposition of zinc on the steel in chloride solution using different concentrations of Taxus baccata extracts as additives was performed using a DC-supply. The presence of the extracts as additives in the electrolytical bath performes the quality of the electrodeposition of the zinc. These constatation was observed throught the deposit parameters as the brightness, the adhesion and the thickness. It was found that the electrodeposition process changed in both additive concentration and extract type. In addition their efficiency against corrosion was evaluated indicating that the samples coated in the presence of extracts were more resistant.