EFFECT OF SHOCK COMPRESSION CONDITIONS ON THE FORMATION OF CUBIC SI₃N₄

Abstract

The yield of cubic γ-Si₃N₄ phase depending on shock compression pressure and temperature and on the type of starting modification (α or β) is studied. Pressure and temperature depend on the power of the explosive and shock-wave loading pattern, KCl content of the charge and its density. The yield of the γ-phase was determined by quantitative X-ray diffraction using calculated intensities of lines from each of the phases. The optimal conditions of shock compression in which the maximum yield of the cubic phase is reached were found (for use of specific explosives). It is concluded that the cubic phase forms from hexagonal modifications by the diffusion mechanism and that the α-phase is metastable.