College of Arts and Sciences (CAS) Publications
Abstract
Scanning electrochemical microscopy (SECM) is used to image variations in electrochemical activity over the surface of an aluminum-based metal matrix composite (MMC) in contact with buffered or unbuffered neutral solutions. The composite consists of an Al - 13.5% Si - 9% Mg alloy matrix and reinforcing silicon carbide particles (SiCp). Feedback mode SECM imaging using ferrocenemethanol as a redox mediator in 0.1 M NaCl solution and in buffer solution (pH 6.8) revealed that the SiC particles are electrochemically active. The data suggest that the electronic conductivity at these sites is higher than that of the Al2O3 film covering the alloy matrix surface. The reduction of dissolved oxygen on the silicon carbide particles was investigated by in situ SECM images of samples and current vs. tip-substrate distance curves. The results with samples of SiCp/Al composites immersed in distilled water alone or in either 0.1 M NaCl or boric acid/borax buffer containing ferrocenemethanol as mediator demonstrate that the silicon carbide particles are conductive and act as local cathodes for the reduction of oxygen.
Publisher
The Electrochemical Society
First Page
B299
DOI
https://doi.org/10.1149/1.1737384
Publication Date
2004
College
College of Arts and Sciences
Department
Department of Chemistry
Keywords
Chemistry, Corrosion, Electrochemistry, Scanning Electrochemical Microsopy, Aluminum, Silicon Carbide, Composites, Metal Matrix Composites
Disciplines
Analytical Chemistry | Materials Chemistry
Recommended Citation
Wipf, David O.; Díaz-Ballote, L.; Veleva, L.; Pech-Canul, M. A.; and Pech-Canul, M. I., "The Activity of Silicon Carbide Particles in Al-Based Metal Matrix Composites Revealed by Scanning Electrochemical Microscopy" (2004). College of Arts and Sciences (CAS) Publications. 24.
https://scholarsjunction.msstate.edu/cas-publications/24
Comments
Postprint manuscript of the accepted article