Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/72419
Type: Artigo de periódico
Title: The roles of macro segregation and of dendritic array spacings on the electrochemical behavior of an Al-4.5 wt.% Cu alloy
Author: Osorio, WR
Spinelli, JE
Ferreira, IL
Garcia, A
Abstract: The microstructural pattern and the solute redistribution of as-east aluminum alloys play an important role on the resulting corrosion behavior. However, of the main aluminum alloys, Al-Cu alloys have the lowest negative corrosion potential. The purpose of this work was to evaluate the electrochemical behavior of an Al-4.5 wt.% Cu alloy solidified under unsteady-state heat flow conditions. This evaluation was carried out through the analysis of both potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) tests in a 0.5 M NaCl solution at 25 degrees C. The experimental segregation profile obtained in the solidification experiment was characterized by positive and negative copper content regions at the bottom and the top of the casting, respectively. Likewise, in conventional foundry practice, in a same casting both positive and negative copper segregation regions may occur. Such casting can exhibit different corrosion responses at different locations. The influences of solute redistribution during solidification, the magnitude of dendritic spacing and hence of the Al-rich phase and of Al2Cu particles distribution along the casting on the corrosion resistance, were examined in samples collected along the casting length. The corrosion rate and impedance parameters (obtained from an equivalent circuit analysis) are also discussed. (c) 2006 Elsevier Ltd. All rights reserved.
Subject: positive and negative macrosegregation
Al-4.5 wt.% Cu alloy
Al2Cu
corrosion resistance and electrochemical behavior
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Rights: fechado
Identifier DOI: 10.1016/j.electacta.2006.10.004
Date Issue: 2007
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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