Preferential alignment of carbon layers around pores in hard carbon and multi-phase graphitization
✍ Scribed by K. Kamiya; K. Suzuki
- Publisher
- Elsevier Science
- Year
- 1975
- Tongue
- English
- Weight
- 457 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0008-6223
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✦ Synopsis
The structure of a phenol formaldehyde resin char and its changes with heat treatment to temperatures from 1600 to 2700°C were investigated by polarized light microscopy and by X-ray diffraction. Concentrical carbon layers were observed to be aligned along the periphery of pores with diameters of the order of 100 km. After removing the peripheral parts by wet oxidation, the specimens were subsequently heat-treated again up to 2700°C: this however produced no indication of graphitization in the residual. These results imply that the graphitization takes place in packets of carbon layers around pores which were formed in the processes of hardening and carbonization of the resin, while the isotropic carbon matrix is left ungraphitized. This may be the mechanism of the so-called multi-phase graphitization in hard carbons.