Synthesis of Cubic Silicon Nitride in a Cylindrical Recovery Capsule

Abstract

Cubic silicon nitride was synthesized from a mixture of hexagonal silicon nitride and copper powder in a cylindrical recovery capsule. It was shown that the synthesis occurred only in the region of the Mach reflection of shock waves near the axis of the capsule. A method of loading the material with ejection of the sample from the capsule into an airtight container was developed. As a result of loading, up to 20% of the starting hexagonal silicon nitride transforms to the cubic phase.

Effects of structural differences in starting materials on the formation behavior of cubic silicon nitride by shock compression

“…6) The third is shock compression of a low-pressure phase, ¡-Si 3 N 4 or ¢-Si 3 N 4 , at above 20 GPa. 7) 12) Polysilazanes, which possess SiN backbones, have been known for decades as precursors to SiN(C) materials. 13) Among polysilazanes, perhydropolysilazane (PHPS) essentially contains only silicon, nitrogen and hydrogen and serves as a precursor for silicon nitride ceramics.…”