Electrochemical investigation on the corrosion of API 5L X52 carbon steel in simulated soil solutions

Potentiodynamic polarization and electrochemical impedance spectroscopy (eis) methods were used to investigate the corrosion behaviour of api 5l x52 carbon steel in simulated solutions of soil. the corrosion rates were estimated at different ph values (4.9,7.0 and 9.0) and over a temperature range 30 to 50 °c. results obtained from potentiodynamic polarization measurements revealed that the corrosion current density increases with increase in temperature signifying an increasing corrosion rate with temperature. the polarization resistance was observed to increase with increase in the ph of the simulated solutions of soil indicative of a reduction in the corrosion rate with increasing alkaline environment. the activation energy for corrosion was found to range from 43-47 kjmol-1 falling within limits of the activation energy of steel corrosion in acidic soils. nyquist plots showed capacitive loops with varying arc sizes depending on the duration of immersion and on the corrosive test solution. impedance curves were matched against an appropriate model to obtain the parameters that characterize the corrosion process. polarization resistance,corrosion current density and corrosion rate parameters of the carbon steel were used to evaluate the soil corrosivity. © 2017,university of mohammed premier oujda morocco.