Wu_mesoscopic.pdf (1.85 MB)
Mesoscopic structure features in synthetic graphite
journal contribution
posted on 2018-02-26, 09:32 authored by Benjamin Maerz, Kenny JolleyKenny Jolley, Thomas James Marrow, Zhaoxia ZhouZhaoxia Zhou, Malcolm Heggie, Roger Smith, Houzheng WuThe mesocopic structure features in the coke fillers and binding carbon regions of a synthetic graphite grade have been examined by high resolution transmission electron microscopy (TEM) and Raman spectroscopy. Within the fillers, the three-dimensional structure is composed of crystal laminae with the basal plane dimensions (La) of hundreds nanometres, and thicknesses (Lc) of tens of nanometres. These laminae have a nearly perfect graphite structure with almost parallel c-axes, but their a-b planes are orientated randomly to form a “crazy paving” structure. A similar structure exists in the binding carbon regions, with a smaller La. Significantly bent laminae are widely seen in quinoline insoluble inclusions and the graphite regions developed around them. The La values measured by TEM are consistent with estimates from the intensity ratios of the D to G Raman peak in these regions. Atomistic modelling finds that the lowest energy interfaces in the crazy paving structure comprise 5, 6 and 7 member carbon rings. The bent laminae tend to maintain the 6 member rings, but are strained elastically. We suggest that a 7 member carbon ring leaves a cavity representing an arm-chair graphite edge contributing to the Raman spectra D peak.
Funding
This work was supported the EPSRC Advanced Materials for Nuclear Fission programme under UNIGRAF: Understanding and Improving Graphite for Nuclear Fission (grant number EP/M018822/1, EP/M018598/1, EP/M018679/1). The EPSRC grant, EP/K040375/1, for the ‘South of England Analytical Electron Microscope’ is also gratefully acknowledged.
History
School
- Science
Department
- Chemistry
Published in
Materials and DesignVolume
142Pages
268 - 278Citation
MAERZ, B. ... et al., 2018. Mesoscopic structure features in synthetic graphite. Materials and Design, 142, pp. 268-278.Publisher
© ElsevierVersion
- AM (Accepted Manuscript)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Acceptance date
2018-01-18Publication date
2018-02-03Notes
This paper was accepted for publication in the journal Materials and Design and the definitive published version is available at https://doi.org/10.1016/j.matdes.2018.01.038ISSN
0264-1275Publisher version
Language
- en