USING METHYL UREA AS INHIBITOR FOR THE CORROSION OF CARBON STEEL IN 1M HYDROCHLORIC ACID MEDIUM

The corrosion behaviour of carbon steel in 1M HCl solution containing various concentration of methyl urea range (10^-3→5×10^-2)M at temperature range (285- 313)K was investigated. The corrosion inhibitive action of methyl urea on carbon steel was studied using weight loss measurement and atomic absorption analysis to find the amounts of dissolved metal in acidic solution in presence and absence of methyl urea. The results showed that urea caused protection efficiency reached to 82% when (10^-3)M methyl urea concentration was used. The coverage (ϴ) of metal surface by methyl urea could be obtained from the rate of corrosion in the presence and absence of methyl urea in the acid solution. Results obtained by gravimetric and atomic absorption are in good agreement. A linear relationship was found to exist between the value of (C/ϴ) and the corresponding methyl urea concentration (C) indicating that the inhibition action occurs via adsorption mechanism. Changes in the free energy, enthalpy and entropy associated with methyl urea adsorption have been determined. Apparent energies of activation have been calculated for the corrosion process of iron in the acid from corrosion rates and Arrhenius plots.