TEM investigation of CVD graphite on nickel

Graphite films have been deposited by chemical vapour deposition from C 2H 4 at 1170 K on polycrystalline Ni substrates. The graphite films were characterized with respect to surface morphology and microstructure. The interface between the deposited graphite and the Ni grains was investigated by transmission electron microscopy. A smooth interface between the graphite and the Ni was observed. Electron diffraction was used to determine orientation relationships between the graphite and the Ni grains. Four different Ni grain orientations were found and for all four the graphite layers grow parallel to the Ni grain surface. A nucleation and growth mechanism involving hydrogen abstraction reactions and formation of polycyclic hydrocarbons has been proposed.