Anticorrosion Film of Benzimidazole on Brass in Ammonia

Department of Chemistry, University of Kalyani, Kalyani-741 235 Manuscript received 8 May 1994, revised 3 August 1994, accepted 3 August 1994 Benzimidazole (Hbz) forms a highly stable insoluble film impeding dissolution of brass in ammonia. It is a mixed inhibitor, inhibiting primarily by blocking the reaction centres. Rise of temperature favours corrosion, but to a much lesser extent in presence of inhibitors, because of chemisorption, leading to a net increase in inhibition efficiency. From ir and electronic spectral measurements, the anticorrosion film has been ascribed to formation of bis-benzimidazolato complexes of CuII and ZnII