INFLUENCE OF PH ON THE DISSOLUTION KINETICS OF IRON IN SULFURIC-ACID-SOLUTIONS

The effect of pH on the kinetics and mechanism of Armco iron (99.99%) corrosion in deaerated, nitrogen saturated solutions at 21 degrees C w as studied. The total concentration of sulphate ions in the solutions tested was 0.5 M. The increase in the pH in the range tested caused a change in the Tafel anodic straight line slope from 28 mV dec(-1) (pH 0.6) to 75 mV dec(-1) (pH 4.15), without a change in the anodic mechan ism. For the anodic dissolution the order of reaction with respect to the OH- ion was found to be -1. The effect of pH on the corrosion pote ntial and current was also found.