Corrosion Inhibition Effect of Methanol Extract of Nerium Oleander on Copper in Nitric Acid Solutions

摘要

Corrosion inhibition and adsorption studies of methanol extract of Nerium oleander for Cu in 0.5 MHNO 3 have been studied by weight loss and electrochemical techniques. Effect of temperature from 30to 50 o C on inhibition action of Nerium oleander extract (NOE) was studied. The inhibition efficiency(IE) of NOE increases with increasing its concentration. The adsorption process and IE were preferredat lower temperatures. Larger negative value of standard free energy was obtained at lower temperature.The polarization data indicated that NOE acts as a mixed type inhibitor. Adsorption isotherm obeyedFrumkin isotherm and NOE was adsorbed physically on the Cu surface. The surface morphology wasinvestigated by scanning electron microscopy (SEM).