Observations on the filamentary growth of graphite

A study has been conducted to show the dependency of the growth of graphite fibers on a metallic impurity. It was seen that heating carbon monofilament by striking a dc arc utilizing a tungsten electrode in a gaseous environment of Ar, N2, and HCl led to the filamentary growth of graphite. If the tungsten electrode was replaced by a carbon one, fiber growth was not observed. Repeating these experiments after removing HCl from the gaseous environment showed no fiber growth in either case. It is proposed that the growth of the fibers can be attributed to HCl reacting with the tungsten to form WCl6 which is reduced to tungsten on the carbon substrate serving as an impurity site.