THE CVD OF PYROLYTIC GRAPHITE

The CVD of pyrolytic graphite is theoretically simple and is based on the thermal decomposition (pyrolysis) of a hydrocarbon gas. The actual mechanism of decomposition however is complex and not completely understood.f l This may be due in part to the fact that most of the studies on the subject of hydrocarbon decomposition are focused on the improvement of fuel efficiency and the prevention of carbon formation (e.g., soot), rather than the deposition of a coating. 

Although many studies of the CVD of graphite have been carried out, a better understanding of the pyrolysis. eactions, a more accurate p.redic-tion of the results, and more complete experimental, thermodynamic, and kinetic investigations are still needed. 

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The CVD of pyrolytic graphite can be optimized by experimentation. The carbon source (hydrocarbon gas), the method of activating the decomposition reaction (thermal, plasma, laser, etc.), and the deposition variables (temperature, pressure, gas flow, etc.) can be changed until a satisfeictory deposit is achieved. However, this empirical eipproach may be too cumbersome and, for more accurate results, it should be combined with a theoretical analysis. 

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