Corrosion influence on surface appearance and microstructure of compo cast ZA27/SiCp composites in sodium chloride solution
(1. Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Belgrade 11000, Serbia;
2. Faculty of Technology and Metallurgy, University of Belgrade, Belgrade 11000, Serbia;
3. "Vin？a" Institute of Nuclear Sciences, University of Belgrade, Belgrade 11000, Serbia)
2. Faculty of Technology and Metallurgy, University of Belgrade, Belgrade 11000, Serbia;
3. "Vin？a" Institute of Nuclear Sciences, University of Belgrade, Belgrade 11000, Serbia)
Abstract: The influence of corrosion on the surface appearance and microstructure of particulate ZA27/SiCp composites was examined after 30 d immersion in a sodium chloride solution with the access of atmospheric oxygen. The composites with different contents of SiC micro-particles were synthesized via compo casting. Microstructural studies by means of optical microscopy (OM) and scanning electron microscopy (SEM) showed that corrosion occurred in the composite matrices, preferentially in regions of the η phase, rich in zinc. The corrosion processes did not affect the silicon carbide particles incorporated in the matrix alloy. According to the results of electrochemical polarization measurements, an increase in the content of SiC particles in the composite matrice has led to the lower corrosion resistance in the composites.
Key words: metal-matrix composites; ZA27 alloy; corrosion; microstructure; polarization resistance; corrosion rate