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The inhibition of aluminium corrosion in potassium hydroxide by “Congo Red” dye, and synergistic action with halide ions

E.E. Oguzie (Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology, Owerri, Nigeria)
G.N. Onuoha (Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology, Owerri, Nigeria)
A.I. Onuchukwu (Electrochemistry and Materials Science Research Laboratory, Department of Chemistry, Federal University of Technology, Owerri, Nigeria)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 1 October 2005

661

Abstract

Purpose

To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in strong alkaline solutions and evaluate the synergistic effect of halide ions on the inhibition efficiency.

Design/methodology/approach

Corrosion rates of aluminium test coupons were determined by gravimetric technique at 30 and 60°C. Inhibition efficiencies of the additives (0.01‐5.0 mM CR and 5.0 mM CR+0.5 mM halides) were evaluated by comparing corrosion rates of the test coupons in 2 M KOH solution in the absence and presence of the additives.

Findings

CR inhibited aluminium corrosion in 2 M KOH by physical adsorption of the dye molecules on the corroding metal surface. Maximum efficiency at 30 and 60°C was 31.72 and 19.32 per cent, respectively. Dye adsorption was enhanced in the presence of halides in the order KCl < KBr < KI, with KI increasing efficiency up to 48.63 and 41.70 per cent at 30 and 60°C, respectively.

Research limitations/implications

Further studies to involve variation of dye and halide concentrations for CR+halide systems to determine the best combination for optimum inhibition synergism.

Originality/value

This paper forms part of an extensive database on the inhibition characteristics of organic dyes for corrosion of different metals in various aggressive environments. This is to serve as a guide to possible applications in metal‐surface anodizing and as additives in surface coatings for service in different environments.

Keywords

Citation

Oguzie, E.E., Onuoha, G.N. and Onuchukwu, A.I. (2005), "The inhibition of aluminium corrosion in potassium hydroxide by “Congo Red” dye, and synergistic action with halide ions", Anti-Corrosion Methods and Materials, Vol. 52 No. 5, pp. 293-298. https://doi.org/10.1108/00035590510615794

Publisher

:

Emerald Group Publishing Limited

Copyright © 2005, Emerald Group Publishing Limited

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