O. Benali

Corrosion inhibition of steel in sulfuric acidic solution by the Chenopodium Ambrosioides Extracts

Abstract The influence of natural occurring extract of Chenopodium Ambrosioides (CAE) on the corrosion inhibition of carbon steel in sulfuric acid solution is studied by the weight loss method, potentiodynamic polarization and impedance spectroscopy (EIS) measurements. The experimental results reveal that extract has a good inhibiting effect on the metal tested in 0.5 M H2SO4 solution. The protection efficiency increases with increasing inhibitor concentration to attain 94% at 4 g/l. Potentiodynamic polarization studies clearly reveal that it acts essentially as a cathodic inhibitor. EIS results show that the change in the impedance parameters (Rt and Cdl) with concentration of extract of Chenopodium Ambrosioides is indicative of the adsorption of molecules leading to the formation of a protective layer on the surface of carbon steel. The efficiency decreases with temperature. The adsorption of Chenopodium Ambrosioides extract is found to obey the Langmuir adsorption isotherm. The activation energies and enthalpies of the corrosion process of carbon steel in acidic medium were determined.

Inhibition of carbon steel corrosion in 1 M HCl medium by potassium thiocyanate

Abstract The effect of potassium thiocyanate (KSCN) on the corrosion of carbon steel (C-steel) in 1 M HCl has been investigated in relation to the concentration of the inhibitor by polarization curves, electrochemical impedance spectroscopy and weight loss measurement. The results obtained revealed that this compound is a good mixed type inhibitor with predominant cathodic effectiveness. The effect of temperature on the corrosion behavior with the addition of optimal concentration of KSCN was studied in the temperature range 298–328 K. The value of inhibition efficiency decreases slightly with the increase in temperature. Changes in impedance parameters (charge transfer resistance, Rct, and double layer capacitance, Cdl) were indicative of adsorption of KSCN on the metal surface, leading to the formation of a protective film. Adsorption of KSCN on the C-steel surface was found to obey the Langmuir adsorption isotherm. Some thermodynamic functions of dissolution and adsorption processes were also determined and discussed.

Carob seed oil: an efficient inhibitor of C38 steel corrosion in hydrochloric acid

BackgroundThe carob seed oil (CO) was tested as inhibitor of the corrosion of C38 steel in 1 M HCl by weight loss and electrochemical measurements. The extract was found to inhibit the corrosion of C38 steel in 1 M HCl.ResultsThe results of the study reveal that the inhibition efficiency of CO depends on its concentration and attains approximately 86.7% at 0.5 g/L. Polarization curves reveal that CO is a mixed-type inhibitor. Changes in impedance parameters (charge transfer resistance, Rt, and double-layer capacitance, Cdl) were indicative of CO adsorption on the metal surface, leading to the formation of a protective film. The effect of temperature on the corrosion behavior with the addition of 0.5 g/L of carob seed oil was studied in the temperature range of 298 to 328 K.ConclusionsResults show that the inhibition efficiency of the plant extract increases with increasing temperature, and the adsorption of the latter on the C38 steel surface is found to obey the Langmuir adsorption isotherm. Some thermodynamic functions of dissolution processes were also determined.