Corrosion Inhibition of Carbon Steel By Some Nonionic Surfactants in 1M H2so4
Authors: Branzoi Florina , Branzoi Viorel , Pacuretu Catalina , Stanca Angela 
Published: February 2020

The inhibitory effect of some nonionic surfactants on the corrosion behavior of two carbon steel type OL 37 and OLC45 in 1M H2SO4 at temperature of 25°C was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FT-IR) and metallurgical microscopy techniques. In the present study, three types of organic inhibitors Span 80, Tween 80 and Tween 60 were investigated.

The effect of inhibitor concentration on the corrosion rate, surface coverage and inhibition efficiency is investigated. Results show that these organic inhibitors exert a strong inhibiting effect on carbon steel corrosion and acts as a mix-type inhibitor. The inhibition efficiency of organic inhibitors may be due to either the adsorption of inhibitor molecules building a protective film or the formation of an insoluble complex of the inhibitor adsorption obeys the Langmuir model. Further, characterization using FT-IR demonstrates the adsorption of inhibitors and the formation of corrosion products on the electrode surface. The inhibition process was attributed to the formation of the adsorbed film on the carbon steel surface that protects the material against corrosive agents. The EIS measurements have confirmed this protection and pointed out the formation of adsorption layers on the electrode surface. The metallographic micrographies made before and after the potentiodynamic polarizations pointed out the evolution of the corrosion process. The addition of the organic inhibitors led in all the cases to inhibition of the corrosion rate.The inhibitory effect of some nonionic surfactants on the corrosion behavior of two carbon steel type OL 37 and OLC45 in 1M H2SO4 at temperature of 25°C was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FT-IR) and metallurgical microscopy techniques. In the present study, three types of organic inhibitors Span 80, Tween 80 and Tween 60 were investigated.

The effect of inhibitor concentration on the corrosion rate, surface coverage and inhibition efficiency is investigated. Results show that these organic inhibitors exert a strong inhibiting effect on carbon steel corrosion and acts as a mix-type inhibitor. The inhibition efficiency of organic inhibitors may be due to either the adsorption of inhibitor molecules building a protective film or the formation of an insoluble complex of the inhibitor adsorption obeys the Langmuir model. Further, characterization using FT-IR demonstrates the adsorption of inhibitors and the formation of corrosion products on the electrode surface. The inhibition process was attributed to the formation of the adsorbed film on the carbon steel surface that protects the material against corrosive agents. The EIS measurements have confirmed this protection and pointed out the formation of adsorption layers on the electrode surface. The metallographic micrographies made before and after the potentiodynamic polarizations pointed out the evolution of the corrosion process. The addition of the organic inhibitors led in all the cases to inhibition of the corrosion rate.