Study on Polycrystalline C_3N_4 Prepared by Blast Shock

A new technique was developed to synthesize the superhard material C3N4 in which high pressure and temperature needed in the reaction were supplied by RDX explosive charge and dicyandiamide(C2H4N4) was used as the primary precursor.The structure,valence-bond character and elemental composition of the sample prepared under 16GPa pressure were characterized by the scanning electron microscope(SEM),X-ray diffraction analysis(XRD),X-ray photoelectron spectroscopy analysis(EDS) and infrared spectrometer(FTIR) respectively.The results show that the XRD pattern is in accordance with the theoretical value,i.e.,α-C3N4,β-C3N4,graphite-C3N4 and intercrystal-C3N4 are recognised in the products.The mass ratio of carbon to nitrogen is about 1.00∶2.98 and nitrogen is mostly bonded with carbon by C-N.Some hexagonal β-C3N4 particles with size of 2μm are observed through SEM.Powder of polycrystalline C3N4 is synthesized successfully and its formation mechanism is discussed.