EFFECT OF cL- ON IRON CORROSION IN H2S-CONTAINING STRONG ACIDIC SOLUTIONS

The effect of Cl-on iron corrosion in 0.5mol/L and 0.005mol/L H2SO4 solutions containing H2S hasbeen studied by electrochemical potentiodynamic polarization and impedance measurements. The resultsshow that Cl-ion can simultaneouly inhibit the anodic and cathodic reaction of iron in 0.5mol/L H2SO4containing H2S. For the inhibition action of Cl- a critical concentration is observed and the critical point is1mol/L. In 0.005mol/L H2SO4 containing H2S, small amount of Cl- can increase the protective propertyof the corrosion product on iron surface, but weaken the adhesive force of the corrosion product, however,large amount of Cl- retard the formation of the corrosion product.