Synthetic graphite is a truly remarkable material whose unique properties have their origins in the material’s complex microstructure. The bond anisot­ropy of the graphite single crystal (in-plane strong covalent bonds and weak interplanar van der Waals bonds) combined with the many possible structural variations, such as the filler-coke type, filler size and shape distribution, forming method, and the distribu­tion of porosity from the nanometer to the millimeter scale, which together constitute the material’s ‘texture,’ make synthetic graphite a uniquely tailorable material.

The breadth of synthetic graphite properties is controlled by the diverse, yet tailorable, textures of synthetic graphite. The physical and mechanical properties reflect both the single crystal bond anisot­ropy and the distribution of porosity within the mate­rial. This porosity plays a pivotal role in controlling thermal expansivity and the temperature dependency of strength in polygranular synthetic graphite. Elec­trical conduction is by electron transport, whereas graphite is a phonon conductor of heat. This complex combination of microstructural features bestows many useful properties such as an increasing strength with temperature and the excellent thermal shock resistance and also some undesirable attributes such as a reduction in thermal conductivity with increasing temperature. The chemical inertness and general unreactive nature of synthetic graphite allow applica­tions in hostile chemical environments and at ele­vated temperatures, although its reactivity with oxygen at temperature above ^300 °C is perhaps graphite’s chief limitation.

Despite many years of research on the behavior of graphite, the details of the interactions between the graphite crystallites and porosity (pores/cracks within the filler coke or the binder and those asso­ciated with the coke/binder interface) have yet to be fully elucidated at all length scales. There is more research to be done.

Acknowledgments

This work is sponsored by the U. S. Department of Energy, Office of Nuclear Energy Science and Tech­nology under Contract No. DE-AC05-00OR22725 with Oak Ridge National Laboratories managed by UT-Battelle, LLC.

This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05- 00OR22725 with the U. S. Department of Energy. The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes.