Inhibition efficiency (IE) of carboxymethylcellulose in controlling corrosion of aluminium in well water at pH11 has been evaluated by weight loss method in the presence and absence of Zn2+ ion. The formulation consisting of 250 ppm of carboxymethylcellulose (CMC) and 25 ppm of Zn2+ has 95% inhibition efficiency. Polarisation study revealed that this formulation controls the cathodic reaction predominantly. AC impedance spectra revealed that a protective film is formed on the metal surface and the protective film was analysed by the technique of scanning electron microscope (SEM) and atomic force microscopy (AFM).
Aluminium, Inhibition efficiency, Protective film, Metal surface, Polarisation study