Inhibitive Action of Sulphonic Acid on the Corrosion of Aluminium in NaOH Solutions

摘要

Corrosion inhibition of sulphonic acid on aluminium in 0.5M NaOH and 1M NaOH at 303K and 313K was studied using gravimetric technique. From the results obtained corrosion rate of aluminium reduced in the 0.5M NaOH and 1M NaOH solutions containing sulphonic acid from what was observed in the NaOH solutions without sulphonic acid. The inhibition efficiency increased as concentration of sulphonic acid increased. The corrosion inhibition of the inhibitor is attributed to its molecules getting adsorbed to the metal surface thereby creating a barrier between the metal surface and corrodent. The trend in thermodynamic parameters like activation energy and heat of adsorption and inhibition efficiency temperature relations, suggested that the inhibitor molecules were chemically adsorbed to the metal surface at 120minutes and below120minutes of the reaction period, but between 120minutes and 150minutes mixed adsorption of chemisorptions-physisorption mechanism was involved. The adsorption of the inhibitor fitted into Langmuir adsorption isotherm.