Corrosion Inhibition of Water-Soluble Polyaniline for Cast Iron

Water-soluble polyaniline was used as a inhibitor for cast iron. The inhibiting ability of the inhibitor for cast iron in 0.2 mol/L H2SO4 was studied using weight loss testing method and scanning electron microscopy (SEM). Experiments showed that the inhibition efficiency increased with the increase in concentration of the inhibitor but decreased with the increase in immersion time and temperature. The adsorption lehavior of the inhibitor molecules on the cast iron surface obeyed Langmuir isotherm at 15 ℃ and 55 ℃, the adsorption equilibrium constant was 9.67 and 2.59 respectively. SEM observations showed that the inhibitor played a significant protective action on cast iron corrosion.