Effect of LaCl3 on Corrosion Behavior of X80 Pipeline Steel in Acid Soil Simulated Solution

Weight loss method, electrochemical method and scanning electron microscopy (SEM) were used to investiguate the corrosion behavior of X80 pipeline steel in Yingtan soil simulated solution with three different concentrations of LaCl3 (0.25 g·L-1, 0.5 g·L-1 and 1.0 g·L-1). The results show that the corrosion rate of X80 steel obviously reduced by LaCl3, and the corrosion rate was the lowest when the concentration of LaCl3 was 0.5 g·L-1. It was because La(OH)3 and La2O3 were produced when LaCl3 combined with OH-, which produced by the cathodic reduction reactions. This makes the corrosion product film more compact and less defective and thus can block the anodic dissolution. Thus, the corrosion rate of X80 steel in acid soil solution decreased effectively by LaCl3.