JMMCE  Vol.10 No.2 , February 2011
Effects of Zinc Addition on the Performance of Aluminium as Sacrificial Anode in Seawater
Abstract: In this work, the effect of zinc addition on the performance of aluminium-based sacrificial anode in seawater was investigated. The parameters used in assessing the performance of the cast anodes are anodic efficiency, protection efficiency and polarized potential. The percentages of Zn in the anodes were varied from 1 to 8%Zn. The alloys produced were tested as sacrificial anode for the protection of mild steel in seawater at room temperature. Current efficiency as high as 86.69% was achieved at 6%Zn in the alloys. The polarized potential obtained for the couples(steel/Al based alloys) are as given in the pourbaix diagrams with the steel lying within the immunity region/cathodic region ( S-0.5V SHE) and the sacrificial anodes within the anodic region. The protection offered by the sacrificial anodes to the steel after the 7th and 8th week were measured. Protection efficiency values as high as 99.26% and 99.13% were achieved after the 7th and 8th with Al-6%Zn. The microstructure showed the intermetallic structures of β-phase which breakdown the alumina passive film and thus enhancing the anode efficiency.
Cite this paper: A. Muazu and S. Yaro, "Effects of Zinc Addition on the Performance of Aluminium as Sacrificial Anode in Seawater," Journal of Minerals and Materials Characterization and Engineering, Vol. 10 No. 2, 2011, pp. 185-198. doi: 10.4236/jmmce.2011.102013.

[1]   Baxter, D. and Britton J. (2006). Offshore Cathodic Protection 101, 10851 Train Court, Houston, USA.

[2]   Talbot, D. and Talbot, J. (1997), Corrosion Science and Technology; CRC Press, LLC, London.

[3]   Unified Facilities Criteria (2005), Cathodic Protection, Department of Defence, United States of America.

[4]   Evans, U.R. (1963); An Introduction to Metallic Corrosion, London Edward Arnold (Publishers) Ltd.

[5]   Corrosion –, htm, (2009).

[6]   Genesca, J. and Juareg, J. (2007), Development and Testing of Galvanic Anodes for Cathodic Protection, Contributions to Science 1 (3): 331 – 334, Catalan, Barcelona.

[7]   Gurappa, J. Corrosion Prevention and Control 44, Pp. 69, India.

[8]   Reboul, M.C., Gimenes, P.H., Rameau, J.J., (1984), Article on Corrosion 40, Pp.366.

[9]   Cathodic Protection Handbook.1997), Theory and Practice of Electrochemical Protection Processes.

[10]   Di Gabriele, F. and Canterbury, J. D. (2003), Corrosion Behaviour of Magnesium Sacrificial Anodes in tap water; Corrosion protection centre, Umist, P O. Box 88, Manchester, M60 1QD, UL.

[11]   Metals Handbooks (1990), Properties and Selection; Nonferrous Alloys and Special – Purpose Material, American Society of Metals (ASM) Vol. 2.

[12]   Shibli, S.M.A., Archana, S.R. and Muhammed, P.A. (2008); Development of Nano Cerium Oxide Incorporated Aluminium Alloy Sacrificial Anode for Marine Applications, Department of Chemistry, University of Karalla, India.

[13]   Meillier, A., A Review of Galvanic Anode Cathodic Protection Design Procedure, Corrosion Control Services Limited,Stafford Park, Telford, U.K.