handbook of carbon, graphite, diamond and fullerenes

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200 400 600 800
Temperature °C
Vitreous Carbon 127
1000
Figure 6.3. Dimensional changes of phenolic resin during carbonization.! 6 '
2.3 Graphitization
Vitreous carbon is essentially a char and generally does not graphitize
to any extent. Heat-treating at 1800°C produces a material with a interlayer
spacing (d) of 0.36 nm and a crystallite size (LJ of 1.5 nm. The crystallite
size is estimated from the broadening of the (110) and (002) lines of the xray
diffraction patterns.
These patterns are not appreciably altered after heating the vitreous
carbon to 2750°C, in contrast with the pattern of heat-treated petroleum
coke which indicates a well-graphitized material as shown in Fig. 6.4.I 7 ! The
crystallite size (Lc) of the vitreous carbon remains small (up to 3 nm) and the
interlayer spacing (d) shows only a slight reduction to a minimum of 0.349
nm.Pl
Heat treatment up to 3000°C causes a volumetric expansion of
approximately 5%J 1 '