Corrosion inhibition by Prussian blue

Abstract

The inhibition efficiency (IE) of K3[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 K3[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 K3[Fe(CN)6] and Zn2+. As immersion period increases, the inhibition efficiency of K3[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.