Authors : Enas Hussien Ali and Takialdin A. Himdan
Abstract: Corrosion of aluminium in 0.6 mol. dm–3 NaCl solution in acidic medium (pH = 1) was investigated in the absence and presence of different concentrations of tannin as environmentally friendly corrosion inhibitor over temperature range (298-313) K. The investigation involved electrochemical polarization method using potentiostatic technique and optical microscopy, the inhibition efficiency increased by increasing inhibitor concentration but decreased with temperature raising. Results showed that the inhibition occurs through adsorption of the inhibitor molecules on the metal surface and it was found to obey Langmuir adsorption isotherm. Some thermodynamic parameters (ΔGads) and activation Energy (Ea) were calculated to elaborate the mechanism of inhibition. The polarization measurements indicated that tannin is of mixed type. The surface characteristic of the inhibited and uninhibited metal samples were investigated by optical microscopy.
Enas Hussien Ali and Takialdin A. Himdan, 2020. Tannin as Corrosion Inhibitor for Aluminium in Acidic Medium. Journal of Engineering and Applied Sciences, 15: 3250-3257.