Synthesis of the B1-type tantalum nitride by shock compression

B1-type tantalum nitride (polycrystalline bulk state) was synthesised by shock compression. Shock-compression recovery experiments of the porous sample of tantalum nitride with a hexagonal structure (CoSn-type) were performed in the impact-velocity range up to 1.5 km/s. The instrumental chemical analysis, X-ray and electron diffraction experiments were carried out on the recovered tantalum nitride sample and the combustion-synthesised B1-type sample for comparison. The recovery rate of the B1-type phase increased with increasing porosity, impact velocity and impactor thickness. Almost 100% recovery rate was achieved for the powder of 70% porosity impacted by a 2 mm thick tungsten plate with velocities above 1.4 km/s. It was confirmed by chemical analysis that the nitrogen content did not change during shock compression. The chemical formulae of the shock-synthesised and combustion-synthesised B1-type phases were estimated to be TaN0.96-0.99 and TaN1.13-1.16,1.27-1.30, respectively. The lattice parameter of the shock-synthesised B1-type (Fm3m) phase was a0 = 0.43363 + (1) nm. The results of X-ray and electron diffraction experiments showed that the shock-synthesised B1-type tantalum nitride had a better stoichiometry compared with the combustion-synthesised ones. 8 refs.