Increase in yield of carbon fibres grown above the iron/carbon eutectic

This paper describes carbon fiber growth from methane in a regime of time and temperature not previously studied: temperatures up to 1208°C and gas phase residence times near 0.5 second. Fiber yield increases sharply >1140°C, a value which is calculated to be near the melting point of the catalyst particles. In fact, the yield curve as a function of temperature may be approximated by calculating the melting points of the measured size distribution of carbon saturated Fe catalyst particles and assuming that the particles can grow fibers only above their melting points. Fibers grown under these conditions are relatively short with no vapor deposited carbon overcoat; their lattice constant d 002 is only 0.340 nm, making them extraordinarily graphitic.