Cu complexes of -Br and -OC[H.sub.2]C[H.sub.3] substituted Schiff bases as corrosion inhibitors for aluminium in acidic media

A group of CU(II), NI(II) and Co(II) complexes of -Br and -OC[H.sub.2]C[H.sub.3] substituted Schiff bases as a new class of corrosion inhibitors for aluminium has been studied in 0.1 M HCl by the addition of 10 ppm compound using potentiodynamic polarization, electrochemical impedance spectroscopy, linear polarization methods and gas evolution tests at 25° C. The inhibition efficiencies obtained from all methods employed are in good agreement. Results show Ni(II) complex of -OC[H.sub.2]C[H.sub.3] substituted Schiff bases was the best inhibitor with a mean efficiency of 69% at 10 ppm additive concentration. The potentiodynamic polarization curves showed both the cathodic and the anodic processes of aluminium corrosion were suppressed, and the Nyquist plots of impedance gave mainly a capacitive loop. Scanning electron microscopy (SEM) was done from the surface of the exposed sample indicating uniform film on the surface.