Corrosion behavior of Al-60 vol.% SiCp composites in NaCl solution

In this study, corrosion behavior of pure Al and Al-4 wt.% Mg alloy matrix composites, comprising 60 vol.% SiC particles, has been investigated. Composites were produced by pressure infiltration technique at 750 degreesC. The corrosion tests were carried out in 3.5 wt.% NaCl environment up to 28 days. The weight loss of the composites increased with increasing duration time up to 3-5 days then remained constant. Scanning electron microscopy (SEM) analysis showed that Al-4 wt.% Mg alloyed matrix composite exhibited higher corrosion resistance than pure Al matrix composite although potentiodynamic polarisation measurements showed higher i(corr) values of Al-4 wt.% Mg alloyed matrix composites than pure Al matrix composites. Experimental results revealed that precipitation of Mg2Si as a result of reaction between Al-Mg alloy and SiC particle has a beneficial effect on corrosion resistance of Al-4Mg alloy matrix composites due to interruption of the continuity of the matrix channels within the pressure infiltrated composites. (C) 2004 Elsevier B.V. All rights reserved.