Shock-compression of C-N precursors for possible synthesis of #beta#-C_3N_4

摘要

We report on the possible synthesis of the theoretically predicted #beta#-phase of carbonnitride (C_3N_4) by shock compression of sodium dicyanamide mixed with sodum azide and carbon tetra-iodide. Shock-compression experiments wer performed on starting precursor blended with approx95 wt. Cu powder, statically pressed in steel capsules. The capsules were impacted under conditions of constant shock amplitude, but varying shock-pulse duration. TEM analysis of the recovered shock-compressed residue showed crystallites of a cubic C-N compound dispersed inan amorphous matrix, with overall yield of the crystalline phase being a function of the shock-pulse duration. Parallel-detection electron energy loss spectroscopy of the nitrogen-containing crystallites revealed diamond-like sp~3 bonding. Infra-red spectrscopy indicated absorption lines in regions calculated to e appropriate for #beta#-C_3N_4.