Use of boron nitride in crystallogenetic experiments to forming carbonados-like agregates

Phase transformations of pyrolytic boron nitride were studied at temperature and pressure conditions providing direct transition of the hexagonal structure to the cubic one. Diamond-like aggregates with a highly equiaxed structure and submicron grain size are formed by martensitic mechanism of cooperative rearrangement of atoms. The presence of solvent-catalyst in the system increases particles size of the cubic phase through recrystallization by the diffusion mechanism. High catalytic activity of solvent-catalyst causes the appearance of directed crystal growth in the synthesized samples.