Effect of Oxygen and Benzotriazole on the Corrosion Characteristics of Rotating Iron Disk Electrodes in Acidic Chloride Solutions

The corrosion behavior of iron in 1M HCl and 0.1M HCl-0.9M NaCl containing various amounts of dissolved oxygen has been investigated with rotating disk electrodes. The reduction of oxygen on iron in acidic chloride solutions is diffusion controlled near the corrosion potential. The diffusion coefficient of oxygen in acidic chloride solutions was determined as 1.4 ± 0.1 × 10^–5 cm²/s from the limiting diffusion currents of oxygen reduction. The addition of benzotriazole significantly decreased the rates of both iron dissolution and hydrogen evolution but decreased only slightly the limiting currents for oxygen reduction.