Synergistic inhibition effect of N-(furan-2-ylmethyl)-7H-purin-6-amine and iodide ion for mild steel corrosion in 1 mol/L HCl

The synergistic inhibition effect of N-(furan-2-ylmethyl)-7H-purin-6-amine (FYPA) and iodide ion on mild steel corrosion in 1 mol/L HCl was investigated using weight-loss tests, electrochemical techniques, and surface analysis. The experiments revealed that the FYPA + KI mixture was a temperature-dependent inhibitor, which strongly inhibited the corrosion of mild steel compared with FYPA. Based on electrochemical results, FYPA and FYPA + KI behaved as mixed-type inhibitors, and their inhibition efficiencies were 73.66% and 96.01%, respectively. The calculated synergistic parameter value was larger than unity, illustrating that enhancement of inhibition in the presence of KI could be a result of synergistic action. Surface analysis techniques (scanning electron microscope/scanning electrochemical microscope) confirmed the presence of additives on the studied mild steel surface. A plausible mechanism of corrosion inhibition was proposed.