Kinetics and synergistic effect of iodide ion and naphthylamine for the inhibition of corrosion reaction of mild steel in hydrochloric acid

The inhibition of mild steel corrosion in HCl solution by naphthylamine (NA), KI and the synergism of KI with NA was studied at different temperatures using weight loss and electrochemical techniques. Electrochemical techniques show that the NA-KI blend is a mixed-type inhibitor. The inhibition efficiency increases with an increase in inhibitor concentration but decreases with a rise in temperature. The adsorption followed the Freundlich isotherm with negative values of , suggesting a stable, and spontaneous inhibition process. The maximum blend efficiency was 95 % at high level of concentration and low level of temperature.