Corrosion Inhibition of Tin in Sodium Chloride Solutions Using Propaneitrile Derivatives

Abstract

Inhibition of corrosion of tin in 0.6 M NaCl by some propaneitrile derivatives namely: (2E)- 3-(1H-indol-3-yl)-3-oxo-2-(3.4-diphenyl thiazol-2(3H)-ylidene)propanenitrile, (E)-3-(1H - indol-3- yl) -3-oxo-2- (5-oxo-3-phenyl thiazolidin-2-ylidene) propanenitrile, (E)-3-(1H-indol-3-yl)-3-yl)-3-oxo- 2-(5-oxo-3-phenyl thiazolidin-2-ylidene) propanenitrile and (2-imino-2H-chromen-3-yl)(1H-indol-3- yl) methadone as investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Polarization studies were carried out at different temperatures and showed that the investigated compounds were mixed type inhibitors. The effect of temperature on corrosion inhibition has been studied and some thermodynamic activation and adsorption parameters were calculated and discussed. The inhibition occurs through adsorption of the investigated compounds on the tin surface without modifying the mechanism of corrosion process. The experimental data fit Freundlich adsorption isotherm.