Experimental and Theoretical Studies to Examine the Inhibition Effect of a Schiff Base Against Magnesium Corrosion

The corrosion inhibition of magnesium by N,N-bis (salicylidene)-2-hydroxy-1, 3-propanediamine Schiff base has been studied in 0.01 M HCl using potentiodynamic polarization and electrochemical noise methods. The polarization curves reveals that the Schiff base used in this study is mixed-type corrosion inhibitor for magnesium and the inhibition efficiency increases as the inhibitor concentration increases. The results obtained by analysis of the electrochemical noise data in frequency domain and those obtained by potentiodynamic polarization measurements are in good agreement. It is found that the Schiff base compound acts by adsorption on the surface and its adsorption follows Fruendlich isotherm. Density function theory calculations shows that stable Mg-2(ligand)(4+) complex can be formed on the surface due to interaction between the Schiff base ligand and Mg2+ ions. Scanning electron microscope images reveals that the damage of magnesium surface diminishes in the presence of the inhibitor.