Synthesis of the B1-type tantalum nitride by shock compression

B1-type tantalum nitride (polycrystalline bulk state) was synthesized 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 1.5kms^–1. The instrumental chemical analysis, X-ray and electron diffraction experiments were carried out on the recovered tantalum nitride sample and the combustion-synthesized B1-type sample for comparison. The recovery rate of the B1 -type phase increased with increasing porosity, impact velocity and impactor thickness; among these above all the effect of porosity was most remarkable. 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 kms^–1. It was confirmed by chemical analysis that the nitrogen content did not change by shock compression. The chemical formulae of the shock-synthesized and combustioned-synthesized B1-type phases were estimated to be TaN_0.96–0.99 and TaN_{1.13–1.16, 1.27–1.30}, respectively. The lattice parameter of the shock-synthesized B1 -type (Fm3m) phase was a_o=0.43363- + (1) nm. The results of X-ray and electron diffraction experiments also supported that the shock-synthesized B1-type tantalum nitride has a good stoichiometry compared with the combustion-synthesized ones.