Apparent catalysis of graphitization. 3. Effect of boron

The catalytic effect of boron on the graphitization behaviour of three diverse industrial carbons has been studied. It is found that the rate of graphitization increases with increasing boron concentration in the ranges of catalyst employed. The activation energy for boron-catalysed graphitization is found to be 963 kJ/mol which is the same as the value obtained for the graphitization of boron-free carbons. To attain the same lattice constant or extent of graphitization at the same residence time, the boronated carbons can be heat-treated at temperatures 400–500 ° C lower than the normal graphitization temperature of boron-free carbons. The increased rate of graphitization is due to the increased pre-exponential factor of the rate equation which is found to be nearly 10 times as great at the 0.5 wt % boron level and nearly 100 times as great at the 1.0 wt % boron level as that of the boron-free carbons.