| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
|
| Presentation Title |
Impact of Grain Boundaries on the Dielectric Behavior of Graphite |
| Author(s) |
Deborah D.L. Chung, Xiang Xi |
| On-Site Speaker (Planned) |
Deborah D.L. Chung |
| Abstract Scope |
It is well-known than grain boundaries and interfaces affect the electrical conduction behavior. However, their effects on the dielectric behavior have not been previously addressed, in spite of the negative effect of electric polarization on electrical conduction. The polarization (DC/AC) is due to the interaction of a small fraction of the charge carriers with the atoms. This work shows that a decrease in the grain size of polycrystalline graphite increases the resistivity slightly, but it increases the permittivity greatly. The carrier-atom interaction occurs mainly at the grain boundaries, which affect the polarization more than conduction. A decrease in the grain size also promotes the electret (permanent electric dipole) behavior, which is consistent with the asymmetry in the DC polarization upon polarity reversal. The graphite is important for electrochemical electrodes, sliding electrical contacts and heating elements, and represents the graphite allotrope family, which includes graphene, carbon fibers and carbon nanotubes. |