THE NUCLEATION AND GROWTH OF GRAPHITE - THE MODIFICATION OF CAST-IRON

It is considered that all forms of graphite, precipitating from a metallic solution, must evolve from a basic hexagonal ring structure, growing into an open monolayer sheet. Subsequent growth of this precursor can lead to multi-layer sheets-flake graphite, to rolled or wrapped concentric shells-spheroidal graphite, or, possibly, to saturated fullerene units. The molecular attachment kinetics which might favor these alternatives are briefly discussed and compared with experimental evidence. Spheroidal graphite is the preferred morphology in a dean melt, flake graphite is an impurity modified form and growth to form fullerenes is presently unpredictable, but is considered to be improbable.