Evolution of Corrosion Films on X52-MS Pipeline Steel in Saturated H2S and Cl- Solution

The morphology, structure and composition of the corrosion product films on X52 MS pipeline steel in 5% NaCl solution with saturated H2S were investigated by weight loss method, surface analysis techniques such as field emission scanning electron microscopy (SEM) and X-ray Diffraction (XRD), electrochemical techniques such as linear potential sweep and electrochemical impedance spectroscopy. The results showed that, in the experimental conditions, the main composition of the corrosion product films was mackinawite FeS, and with the increase of time, the thickness of the corrosion product films increased gradually, and the structure became dense. In addition, not only the average corrosion rates of weight loss, but also the instant current density both reduced with the time increased. The relatively dense corrosion product films had some protection properties, which could inhibit the general corrosion of X52 MS pipeline steel.