This is a study of the initiation and growth mechanisms of filamentous carbon on nickel, cobalt, and the alloys of nickel, cobalt, and iron. Computer.generated phase diagrams are used to control solid "surface" and bulk compositions. The gas phase consists of mixtures of carbon monoxide, carbon dioxide, methane, hydrogen, and water. Experiments are performed in an isothermal, differential, gravimetric reactor. Filament and solid structures are observed using electron microscopy along with metallurgical etching. Solid.phase identification is performed using X.ray and/or electron diffraction and magnetic susceptibility measurements. Laser interferometry and laser speckle metrology are used to generate low.temperature "surface" phase diagrams and explore crystalline orientation effects on filament initiation and growth. Carbon filaments grow as a result of catalytic decomposition of carbon.bearing gases on iron, nickel, or cobalt, or their alloys. These filaments can be used in high.strength, low.weight composites. However, they are also a serious corrosion problem for many transition.metal.based alloys and catalysts.
