Two kinds of mesocarbon microbeads (MCMBs) with different chemical composition have been synthesized. The MCMBs were molded and heat treated at temperatures above 2000 °C to obtain graphite blocks. The effects of chemical composition of MCMBs on the pore morphology, carbon texture and thermal properties of the derived graphite blocks have been explored. The pore morphology was investigated by small angle X-ray scattering technique and a graphitization-induced morphology transition was observed. When the graphitic crystallite size exceeded a threshold value, the association of crystallites and migration of randomly distributed pores took place extensively. For the graphite blocks made of MCMBs which had light components with higher aromaticity value, the growth of crystallites caused a significant enhancement in thermal conductivity for the specimens. However, for the other kind of MCMBs, their light components tended to form solid porous carbon texture after graphitization, and the thermal conductivity coefficients of their graphite blocks could only increase slightly as crystallites grew. It was suggested that the thermal resistance at the granule’s boundary became noticeable in the latter case and thus the growth of thermal conductivity coefficients was prominently hindered.

    Abstract
    1 Introduction
    2 Materials and methods
        2.1 Materials and fabrication of graphite blocks
        2.2 Characterization of graphite blocks
    3 Results and discussion
        3.1 Characterization of MCMBs
        3.2 Pore morphology of graphite blocks
        3.3 Thermal conductivity coefficients of graphite blocks
    4 Conclusions
    Acknowledgements 
    References

• Jen‑Yung Hsu(New Materials Research & Development Department, China Steel Corporation)
• Chun‑Jen Su(National Synchrotron Radiation Research Center)
• Yung‑Lin Yen(Research & Development Department, China Steel Chemical Corporation)
• Che‑Yun Lee(Research & Development Department, China Steel Chemical Corporation)