Corrosion Inhibition of Zn-Al-Cu Alloy by 2-Aminothiazole

The inhibitive effect of 2-aminothiazole on corrosion of Zn-Al-Cu alloy was investigated in acid, neutral and alkaline media by impedance and polarization techniques. The impedance data were fitted to a simple equivalent circuit model and indicated control by a diffusion process. Satisfactory inhibition was obtained in alkaline and neutral media. On the other hand, quite low inhibition efficiency was observed in acid medium. Increase in concentration of the inhibitor increased the inhibitive effect, whereas the reverse was observed when the temperature was increased. Different adsorption isotherms were tested in neutral and alkaline media, the best fit was obtained for the Freundlich isotherm. The highest value for the free energy change was recorded in alkaline medium in accordance with the high inhibition efficiency observed in this medium.