Graphitization of synthetic diamond crystals: A morphological study

In the present work, the morphological and structural evolution occurring upon graphitization of synthetic diamond microcrystals of cuboctahedral shape at 1600 °C during vacuum annealing was studied. The most developed facets of the initial diamond crystals are octahedral {111} and cube {100} facets. It was found that graphitization starts from the vertices and edges of the crystals. The {111} facets were more prone to graphitization than the {100} facets. Annealing of the partially graphitized diamond microcrystals in air helped revealing the orientation relationship of the forming graphite platelets with the parent diamond substrate. The graphite structures forming upon full graphitization of the diamond microcrystals retained the shape of the initial crystals. • Graphitization of synthetic diamond microcrystals at 1600 °C was studied. • Graphitization starts from the vertices and edges of the crystals. • {111} facets are more prone to graphitization than {100} facets. • Annealing in air helps reveal graphite platelets/substrate orientation relationship. • Graphite structure forming on full graphitization retains shape of initial crystal.