Musa acuminata (Green corrosion inhibitor) as anti-pit and anti-cracking agent for mild steel in 5M hydrochloric acid solution

Abstract

• Dried peel of fruit of Musa acuminate was tested as green corrosion inhibitor. • Weight loss, Gasometric, electrochemical polarization and impedance spectroscopy (EIS) techniques were used. • SEM and metallurgical research microscopy study was carried out for the surface study. • Warburg impedance ( Z w ), faradaic current (I F ), capacitive current ( I c ), charge transfer Resistance, r ct and capacitive loop were observed. • 90.00% corrosion inhibition efficiency was observed for mild steel. • Musa acuminate proved to be anti-pit and anti-cracking agent for mild steel in acidic medium. Musa acuminata (Banana peels) was tested as green corrosion inhibitor (GCI) for controlling the problems of pitting and cracking corrosion of mild steel (MS) when comes in contact with 5 M HCl solution. Immersion test, gasometric, electrochemical polarization and impedance spectroscopy (EIS) techniques were employed for the corrosion study. SEM and metallurgical microscopy studies were carried out for the surface study of corroded specimens which confirms the adsorption of GCI molecules on MS surface. Surface study proves the formation of uniform, nonporous film over MS surface confirmed by decline in Faradaic current, increase in capacitive current ( I c ), charge transfer resistance, R ct (8.76 to 33.41 Ωcm 2 ), Warburg Impedance ( Z w ) and capacitive loop in Nyquist plot. High percentage corrosion inhibition efficiency i.e. 90.00% was observed for MS in presence of 4 g/L dried fruit peels of Musa acuminata in 5 M HCl solution. No evidence of pitting and cracking corrosion was seen on the surface of MS treated with Musa acuminate as GCI. Nyquist plots (EIS) of mild steel immersed in 5.0 M HCl.