The Detection and Analysis of Electrochemical Damage in Bismaleimide/Graphite Fiber Composites
| Autor: | G. L. Cahen, S. R. Taylor, F. D. Wall |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Materials science
Aqueous solution Renewable Energy Sustainability and the Environment Composite number Condensed Matter Physics Electrochemistry Surfaces Coatings and Films Electronic Optical and Magnetic Materials Anode Cathodic protection Dielectric spectroscopy Materials Chemistry Galvanic cell Composite material Polarization (electrochemistry) |
| Zdroj: | Journal of The Electrochemical Society. 143:449-458 |
| ISSN: | 1945-7111 0013-4651 |
| Popis: | The use of advanced graphite fiber polymeric matrix composites in multimaterial assemblies which must maintain mechanical integrity in aqueous environments has initiated interest in the galvanic degradation of these materials. Of recent concern is the galvanic degradation of bismaleimide (BMI)/graphite fiber (GF) composites. This study has used electrochemical impedance spectroscopy to monitor material interfacial changes in an 8 ply, 0°, unidirectional BMI-GF composite subjected to cathodic and anodic polarization in NaCl solution, exposure to caustic solutions, and galvanic coupling with various metals in NaCl solution (Al, Fe, Cu, Ti). Cathodic polarization was found to produce porous electrode behavior which was attributed to breakdown of the fiber/matrix interface and subsequent moisture ingress. This is in contrast to caustic exposure which did not show a porous electrode response, presumably due to general BMI solvation. Results indicate that reaction intermediates generated during the oxygen reduction reaction, e.g., peroxide and superoxide radicals, and not OH ions are the key damaging species. This will have important implications on the development of more damage resistant polymer chemistries. Couples to titanium, previously believed to be a benign couple, caused changes in the impedance spectra similar to those for low cathodic overpotentials. The long-term implications of these changes on composite durability are not known at this time, and warrant further evaluation. |
| Databáze: | OpenAIRE |
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