Abstract
The aim of the present work was to report the effect of increasing the immersion time and the solution temperature on the electrochemical corrosion behavior of API 5L grade X-65 pipeline steel in 1.0 M H2SO4 pickling solutions using different experimental measurements. The potentiodynamic polarization results showed that increasing the immersion time from 10 min to 60 min and further to 24 h for the steel in the sulfuric acid solution before measurements increased the anodic and cathodic currents and corrosion current density (j(Corr)) and decreased the polarization resistance (Rp). Electrochemical impedance spectroscopy (EIS) measurements confirmed the polarization data that the increase of immersion time decreases the solution and polarization resistances. Both polarization and EIS data also revealed that increasing the solution temperature in the range from 20 degrees C to 60 degrees C highly increased the corrosion of the X-65 steel due to the faster and contentious dissolution of the surface with temperature. Results collectively were consistent with others and proved clearly that the corrosion of the investigated steel in the 1.0 M H2SO4 solution increases with elongating the immersion time as well as increasing the solution temperature.