Kinetic studies of the graphitization process—I Effect of ambient gas phase on the rate of graphitization

✍ Scribed by T. Noda; M. Inagaki; T. Sekiya

• Publisher: Elsevier Science
• Year: 1965
• Tongue: English
• Weight: 649 KB
• Volume: 3
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(65)90045-x

✦ Synopsis

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-The influence of ambient gas phase on the graphitixation rate of carbons was investigated. A calcined petroleum coke was heat treated in a high purity graphite tube furnace for various residence times at a maximum temperature ranging from 1900"-2400°C under air pressure of 4, 2 and 0.1 Torr. For each heat treated sample, the lattice constant c,, the crystallite dia. La and the size of the threedimensionally arranged region Llls were measured. The results show that the presence of oxygen in the ambient gas phase accelerates the graphitization. For heat treatments under gas pressure of 2 and 4 Torr the relation between log (c&708) and residence time was found to be linear and seems to consist of two stages. In the first stage of graphitization, c0 decreases from the original value to about 6.76 A, and L, increases rapidly to about 1000 A. The activation energy for the first stage is estimated to about 75 kcaljmole in both cases. For heat treatment under 0.1 Torr, on the other hand, no linear relation is observed; an activation energy of about 180 keal/mole is obtained using Fischbach's method.