Polycrystalline nickel was reacted at 680 °C with a carbon-supersaturated CO/H_2/H_2O gas. Graphite deposited on the metal surface as (a) very thin (20-200 rrm) layers on a smooth metal surface, (b) thick (1-2 mu m), relatively uniform layers which developed serrated incursions into the metal, and (c) nodules which stood proud of, and protruded into, the metal surface. The thin, benign graphite deposits formed on {002} nickel surfaces but thicker graphite layers grew on {111} surfaces. Thickening of that layer, and graphite nodule growth, were both associated with the inward growth of graphite basal planes parallel to nickel {111} and {113} planes located within the metal interior. Microanalysis showed that the graphite contained nickel, which was identified by dark-field imaging and selected-area diffraction as nanoparticulate metal. These nanoparticles are thought to have resulted from metal disintegration caused by the volume expansion accompanying graphite nucleation and growth.
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