Inhibition of Al-Mg alloy in hydrochloric acid using Schiff bases as corrosion inhibitors

The effect of some new synthesized Schiff bases namely o-Chloroaniline-N-(p-methoxy benzylidene) and p-Chloroaniline-N-(p-methoxy benzylidene) on the corrosion of Al-Mg alloy in 2 M HCl was investigated. The investigation involved weight loss, galvanostatic polarization and EIS measurements. The inhibition efficiency increased with increase in inhibitor concentration but decreased with increase in temperature. Schiff bases are found to adsorb on the metal surface according to the Langmuir isotherm. Thermodynamic parameters and activation energy were calculated to elaborate the mechanism of inhibition. The results of polarization method show that these Schiff bases act as mixed type, but the cathode is more preferentially polarized.