This is an investigation of the chemistry occurring on and within catalyst particles that causes carbon filaments to grow in various conformations. Filaments can be formed in three basic conformations: whisker-like, branched, and multidirectional. Specific issues include the effects of the crystallographic features of the catalyst particle on the mechanism of the hydrocarbon decomposition reaction; how reaction conditions influence the structural characteristics of carbon filaments produced from a given catalyst hydrocarbon system; and the effects that the introduction of a second metal into the catalyst has on carbon diffusion pathways. A combination of techniques are used to study these aspects including controlled-atmosphere electron microscopy (CAEM), high-resolution transmission electron microscopy (HRTEM) with in-situ electron diffraction, specialized in-situ surface spectroscopy, carbon-13 nuclear magnetic resonance, and bulk kinetic studies. The notion of growing carbon filaments onto the surfaces of primary fibers by catalytic decomposition of a hydrocarbon offers the potential of producing a new generation of composites with unique physical, chemical, and electronic properties. Carbon filaments are produced by the catalytic decomposition of hydrocarbons on small metal particles. Iron, cobalt, or nickel promote this process. The filaments have a duplex structure - a graphitic skin surrounding a core that is more easily oxidized.
