Stability of graphite intercalation compounds with TaCL5 or NbCL5 against water or dilute acids a study with xrd, sem/eds and electron microprobe analysis (EMPA)
✍ Scribed by J. Walter; H.P. Boehm
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 573 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0008-6223
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✦ Synopsis
Graphite intercalation compounds were prepared from flakes of natural graphite and Thornel P-120 carbon fibers. Stage 2 compounds were obtalned with TaCI, at 400 C, and stage 4 compounds with NbClj at 200 C. The compounds with TaCI, were stable in amblent air or under water at 25-C. At 90 C with water or dilute hydrochloric acid small quantities of the stage 3 compound appeared. The NbCI, compound did not change at all under these conditions. In contrast. the intercalated Thornel P-120 fibers were deintrrcalated after 30 minutes' exposure to air. Pomt analysis by EDS of the exposed flakes showed onl! Ta (or Nb) and ('I to be present in the central regions of the flakes whilst oxygen could be detected III addition m a small border zone at the edge of the flakes of a few micrometers width. Quantitative electron microprobe analysis (EMPA) Indicated that TaOCI, had formed. This polymeric and therefore immobile compound protects the mterlor from attack by water. The diameter of the fiber is too small to allow protection by this mechanism Key Words-Electron mlcroprobe analysis. de-intercalation. graphite intercalation compounds. intercalated carbon tibers. KbCI,-graphite. TaCl,-graphite. stability in air or water. I. INTRODt>CTION