THE STRUCTURE OF PYROLYTIC CARBON
X-ray diffraction with electron and optical microscopy were used in the study of pyrolytic carbon deposits prepared in the range 850 to 2100 deg C. Investigations of material deposited on an electrically heated rod indicated that a severe temperature gradient was set up in the growing layer, leading to marked annealing of the inner layers. Substrate roughness was found to account for the growth of the large cones visible optically when the material is viewed in section. Preferred orientation measurements showed that greatest misorientation occurred for material deposited at about 1700 deg C (corresponding to the density minimum). Preliminary graphitization studies showed that a 2000 deg C deposit did not graphitize completely at about 2400 deg C but reached a quasi-stable state in which 60 to 70% of the layer planes were oriented as in the ideal graphite structure. No changes in preferred orientation or macroscopic dimensions occurred but electron microscope observations suggested that a kind of polygonization had taken place. Material with c planes inclined to the surface graphitized less readily than that with c planes parallel. The results are interpreted in terms of a proposed structure resulting from the incorporation, in the growing deposit, of small carbon black particles from the gas phase. (auth)
- Research Organization:
- Gt. Brit. Royal Aircraft Establishment, Farnborough, Hants, England
- NSA Number:
- NSA-17-035697
- OSTI ID:
- 4643642
- Report Number(s):
- RAE-TN-MET-PHYS-361
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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