The corrosion behavior of mild steel in 11% hydrochloric acid solution (HCl) and the effect of using black pepper as a corrosion inhibitor has been studied. Specimens were exposed in the acidic media for maximum five days and corrosion rates evaluated, using the weight loss method. The results indicate that the black pepper functioned as a good corrosion inhibitor in this environment and inhibition efficiency increased with increasing the inhibitor concentration. The effect of temperature from 25 oC to 45 oC revealed an increase in inhibition efficiency with rise in temperature and activation energies decreased in the presence of the inhibitor. Moreover, the thermodynamic parameters of the adsorption process free energy of adsorption, enthalpy and entropy were calculated the values of these parameters showed good interaction. The order of the reaction obtained from graph between logarithm concentration of inhibitor vs. logarithm corrosion rate of mild steel indicts that it is first order reaction.
Mild steel, Hydrochloric acid, Corrosion inhibition, Black pepper, Weight loss tech, Langmuir kinetic parameters