New (Z)-N'-(1-phenylethylidene) benzohydrazide as Corrosion Inhibitors for Carbon Steel in 1 M HCl Solutions
A.S. Fouda 1, K. Shalabi1, A.E.El-Shennawi2, R.M. Abo Shohba2, A.A.El-Naggar2
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The corrosion inhibition of carbon-steel in 1 M HCl by some (Z)-N'-(1-phenylethylidene) benzohydrazide derivatives (PEBH) has been investigated using weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. Results obtained showed that these investigated compounds are good inhibitors and their inhibition efficiencies increase with increasing inhibitor concentration and decrease with increase in temperature. Moreover, polarization studies clearly revealed that the presence of inhibitors changes the mechanism of hydrogen evolution and the metal dissolution i.e. they act as mixed type inhibitors. EIS study showed that charge transfer resistance increases with the increase of inhibitor concentration but the capacitance of double layer decreases. The adsorption of investigated compounds obeys Langmuir’s adsorption isotherm. The activation parameters were determined and discussed. The mechanism of adsorption had been explained on the basis of chemical structure of the investigated inhibitors. It was found that there is a good agreement between the different tested techniques.