Glutamic Acid as Corrosion Inhibitor for Aluminium in Acidic Medium

Corrosion behavior of aluminium in 0.6 mol. dm-3 NaCL solution in acidic medium (pH= 0.7) was investigated in the absence and presence of different concentrations of aminoacid, glutamic acid, as environmentally – friendly corrosion inhibitor over temperature range(293-308)K. The investigation involved electrochemical polarization method usingpotentiostatic technique and optical microscopy, the inhibition efficiency increased with anincrease in inhibitor concentration but decreased with increase in temperature. Results showedthat the inhibition occurs through adsorption of the inhibitor molecules on the metal surfaceand it was found to obey Langmuir adsorption isotherm. Some thermodynamic parameters(ΔGads.) and activation energy (Ea) ere calculated to elaborate the mechanism of corrosioninhibition. The polarization measurements indicated that glutamic acid is of mixed type. Thesurface characteristic of the inhibited and uninhibited metal samples were investigated byoptical microscopy.