Electrochemical corrosion behavior of X-65 steel in the simulated oil-sand slurry. II: Synergism of erosion and corrosion

Erosion-corrosion (E-C) of X-65 pipe steel was investigated in a simulated oil-sand slurry through an impingement jet system. Measurements of weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy combined with optical microscopy observation were performed to determine the synergism of corrosion and erosion in E-C of steel. It was found that passivity of the steel developed in static oil-water emulsion cannot be maintained in the flowing fluid due to the enhanced activity of the steel upon impingement of the emulsion/slurry. The effect of slurry impact angle on E-C of steel is complex, depending oil the magnitude and synergism of shear stress and normal stress exerting on the electrode surface, enhancing the steel E-C by degrading the oxide film formed on the steel surface. There is a synergism of corrosion and erosion in E-C of steel. The contributions of corrosion and erosion to E-C rate of the steel in oil-sand slurry rank approximately 30% and 70%, respectively. Erosion dominates the E-C of X-65 steel in oil-sand slurry. (c) 2008 Elsevier Ltd. All rights reserved.