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

Abstract

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 () 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/) 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.