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Activation of an Al-Zn-Mg-Li alloy by the Presence of Precipitates to be used as Sacrificial Anode

Published online by Cambridge University Press:  21 March 2011

S. Valdez ,
M. A. Talavera ,
J. Genesca  and
J. A. Juarez-Islas
S. Valdez
Affiliation:
Instituto de Investigaciones en Materiales, de Mexico, Circuito Escolar S/N, Cd. Universitaria, 04510, Mexico, D.F. Mexico
M. A. Talavera
Affiliation:
Fac. de Quimica, Universidad Nacional Autonomade Mexico, Circuito Escolar S/N, Cd. Universitaria, 04510, Mexico, D.F. Mexico
J. Genesca
Affiliation:
Fac. de Quimica, Universidad Nacional Autonomade Mexico, Circuito Escolar S/N, Cd. Universitaria, 04510, Mexico, D.F. Mexico
J. A. Juarez-Islas
Affiliation:
Instituto de Investigaciones en Materiales, de Mexico, Circuito Escolar S/N, Cd. Universitaria, 04510, Mexico, D.F. Mexico
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Abstract

This work reports the influence of microstructure on the electrochemical efficiency of Al- alloys to be used as sacrificial anodes. The microstructure of as-cast Al-ingots was characterized by X-ray diffractometry and scanning electron microscope (equipped with WDS microanalysis facilities). The electrochemical behavior was investigated in 3% NaCl solution simulating sea water at room temperature. Regarding microstructure, X-ray diffractometry detected the presence of the α-Al phase, and the τ-Al2Mg3Zn3, Mg7Zn3 and δ-AlLi precipitates. SEM observations confirmed the presence of α-Al dendrites with τ-Al2Mg3Zn3 and Mg7Zn3 particles in matrix. In interdendritic regions, it was observed the presence of the eutectic α-Al + τ-Al2Mg3Zn3 plus some primary Mg7Zn3 particles. δ-AlLi particles were identified at this step only by X-ray diffractometry. Finally, it was detected that an uniform distribution of precipitates in the α-Al dendrites together with an uniform distribution of a fine eutectic gave as a result in as-cast ingots an electrochemical efficiency up to 61.4 %.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 654: Symposia AA – Structure-Property Relationships of Oxide Surfaces & Interfaces , 2000 , AA3.5.1
Copyright
Copyright © Materials Research Society 2001

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References

1. Juarez-Islas, J.A., Tsakiropoulos, P. and Jones, H., Int. Journal of Rapid Solidification, 5 (1990) 177.Google Scholar
2. Barbucci, A., Cerisola, G., Bruzzone, G. and Saccone, A., Electrochemica Acta, 42 (1997) 2369.Google Scholar
3. Valdes, S., Genesca, J., Mena, B. and Juarez-Islas, J. A., in press, Materials Science and Technology, 2000.Google Scholar
4. Despic, A. R., J. Appl. Electrochem. 6 (1976) 499.Google Scholar
5. Salleh, M., Ph. D Thesis, UMIST, Manchester, U. K., 1978.Google Scholar
6. Clark, J. B., Trans. Am. Soc. Met., 53 (1961) 295.Google Scholar
7. Reading, J. T. and Newport, J. J., Mater. Protect., 5 (1966) 15.Google Scholar
8. Salinas, D. R. and Bessone, J. B., Corrosion 47 (1991) 665.Google Scholar
9. Salinas, D. R., Garcia, S. G. and Bessone, J. B., J. Appl. Electrochem., 29 (1999) 1063.Google Scholar
10. DNV Recommended Practice RP B401 (1993): “Cathodic Protection Design”, Det Norske Veritas Industry AS, Hovik, 1993.Google Scholar
11. Standard Specification for Substitute Ocean Water, ASTM D1141-75.Google Scholar
12. Foley, R.T. and Trzaskoma, P.P., in Passivity of Metals, Frankental, R.P. and Kruger, J. Editors, The Electrochemical Society, New Jersey (1978):p. 337.Google Scholar
13. NACE Standard Test Method “Impressed Current Laboratory Testing of Aluminum Alloy Anodes”, NACE Standard TM0190-98. NACE International, Houston, 1998.Google Scholar