Corrosion Inhibition by Prussian Blue

The inhibition efficiency (1E) of K-3[Fe(CN)(6)] in controlling corrosion of carbon steel in aqueous solution containing 60 ppm of Cl- in the presence and absence of Zn2+ has been evaluated by weight loss method. The formulation consisting of 100 ppm K-3[Fe(CN)(6)] and 50 ppm Zn2+ offers 98% inhibition efficiency to carbon steel immersed in aqueous solution containing 60 ppm Cl-. A synergistic effect exists between K-3[Fe(CN)(6)] and Zn2+. As immersion period increases, the inhibition efficiency of K-3[Fe(CN)(6)]-Zn2+ system decreases. Polarization study reveals that this formulation controls the cathodic reaction predominantly. AC impedance spectra reveal that a protective film is formed on the metal surface. FTIR spectra reveal that the protective film consists of Prussian blue and Zn(OH)(2). The film is found to be UV fluorescent.