Extrato hidroetanólico de folhas de Senna pendula como inibidor de corrosão do aço carbono 1020

Abstract

The present study aimed to evaluate the efficiency of the hydroethanolic extract (10% v/v) of Senna pendula leaves, which contain antioxidant compounds belonging to the flavonoid and anthraquinone classes, in inhibiting the corrosion of carbon steel 1020 (1.96 cm2) in 0.5 mol L-1 HCl medium. For this study, mass loss tests were performed in 500 ppm of extract and electrochemical techniques of linear potentiodynamic polarization (PPL) and electrochemical impedance spectroscopy (EIE) were used in concentrations of 0, 500, 1000 and 2000 ppm. In the mass loss tests, the immersion times were 0.5, 1 and 24 hours. The inhibition efficiency results were 54.3, 54.4 and 80.1%, respectively. The results of the PPL curve showed that with the increase in concentration there was a decrease in the corrosion efficiency, from 80.1 to 21.3% for 500 and 2000 ppm, respectively. In the IEE tests, the efficiency increased proportionally to the increase of the concentration presenting a maximum value of 97.1% for 2000 ppm, proving that Senna pendula is an inhibiting potential.