The beneficial influence of halide ions on the inhibition characteristics of nitrogen‐containing organic inhibitors to reduce the corrosion rate of carbon steel in HCl

The beneficial effect of halide ions on the inhibition of corrosion of carbon steel in 20 per cent HCl solution in the presence of some nitrogen‐containing compounds, cetyl pyridinium chloride, cetyl pyridinium bromide, and hexamine was investigated using potentiodynamic polarisation measurements. Potentiodynamic polarisation studies revealed that all the tested compounds were of anodic‐type inhibitors. All of the compounds were able to reduce the corrosion of carbon steel and their performance was enhanced by the addition of iodide ions. The increase in surface coverage in the presence of the iodide ions indicated that iodide ions enhanced the absorption of inhibitor compounds on the metal surface. Auger electron spectroscopic analysis confirmed the joint absorption of the compounds with KI.